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Classifications

Harrison's Part

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Mappings

MONDO

MONDO:0008327 exfoliation syndrome

MONDO:0008327 is the disease concept proper (synonyms XFS, XFG, pseudoexfoliation glaucoma; cross-referenced to DOID:13641, MeSH D017889, Orphanet 529819 and NCIT C129025). This entry curates that disease in full, so the mapping is an exact match rather than a cross-reference.

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Inheritance

1

Polygenic inheritance HP:0010982

Familial aggregation is well documented and the LOXL1 locus carries an extraordinary population attributable risk, yet the same variants are carried by most unaffected people and the disease is strongly age-dependent, so inheritance is polygenic with incomplete, age-related penetrance rather than Mendelian. Additional genome-wide loci (CACNA1A, POMP, TMEM136, AGPAT1, RBMS3, SEMA6A) and rare CYP39A1 variants each add modest risk.

Polygenic inheritance Penetrance: INCOMPLETE Expressivity: VARIABLE

Show evidence (3 references)

PMID:23157966 SUPPORT Other

"PXS familial aggregation suggests genetic inheritance."

Establishes the familial clustering that motivates a genetic model, while stopping short of a Mendelian claim.

PMID:23157966 SUPPORT Other

"Two of these SNPs confer a higher than 99% population attributable risk for PXS and PXG in the Nordic population; however, they carry different risks in different populations."

A near-total population attributable risk from common alleles that carry different risks in different populations is the signature of a complex susceptibility locus, not of a causal Mendelian gene.

PMID:25188364 SUPPORT Human Clinical

"However, 80% of controls also harbor these variants and the ratio of cases to controls with trait-related variants is fairly similar in regions where XFS is hyper-endemic"

Risk-allele carriage in four fifths of unaffected controls is the incomplete penetrance that makes the polygenic, gene-environment model necessary.

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Discussions and Knowledge Gaps

4

What is the functional LOXL1 lesion, given that the coding risk alleles reverse direction between ancestries, and what initiates fibrillogenesis in a person who carries it?

KNOWLEDGE GAP OPEN xfs_loxl1_allele_reversal_and_initiating_lesion

Attached to

pathophysiology#LOXL1 Susceptibility Genotype pathophysiology#Dysregulated LOXL1 Expression and Elastic Microfibril Cross-Linking

The LOXL1 association is among the strongest in complex disease and among the least understood. The coding variants cannot be causal in a simple sense because the risk allele at rs3825942 is protective in black South Africans and the rs1048661 risk allele is protective in East Asians; the regulatory variant rs11638944 lowers LOXL1 mRNA in carriers, yet ocular LOXL1 is increased in early disease; and Loxl1-null mice form no material. Whether the disease is a proteopathy of a misfolding-prone LOXL1 N-terminus, a stage-dependent dysregulation of an otherwise normal enzyme, or a stress-response defect mediated through LOXL1-AS1, the three current models make different predictions about which patients will progress and what a disease-modifying therapy should do, and none has been tested in vivo. The patient-derived fibroblast work that supports the proteopathy model uses trabeculectomy specimens from advanced glaucoma, so it may be reporting late consequences rather than initiation.

Proposed experiments

Ancestry-stratified fine mapping and allele-specific expression at LOXL1

xfs_ancestry_stratified_loxl1_fine_mapping

Fine-map the LOXL1 locus in the ancestries where the coding alleles reverse, using allele-specific expression in anterior-segment tissue from cataract surgery, to identify a regulatory haplotype whose direction of effect is consistent across populations. A variant that behaves the same way in South African and Icelandic eyes would be the functional lesion; the coding SNPs have already failed that test.

Can the Loxl1-null mouse, which loses elastic fibres but forms no exfoliation material and develops no glaucoma, inform the ocular mechanism of the human disease at all?

HUMAN MODEL MISMATCH OPEN xfs_no_faithful_animal_model

Attached to

pathophysiology#Exfoliation Material Fibrillogenesis and Deposition animal_models#Loxl1-null mouse

The mismatch is mechanistically meaningful in both directions. The mouse shows that LOXL1 loss alone does not make exfoliation material, which supports the human genetics in saying that LOXL1 sets susceptibility rather than causing disease; but it also means every human mechanism between genotype and deposit (the TGF-beta1 milieu, chaperone deficiency, aggregation of microfibrillar components) rests on human tissue and cultured cells with no in vivo test. The model reproduces the systemic elastic-tissue arm faithfully enough that pelvic organ prolapse in Loxl1-null mice is the best mechanistic support the human prolapse association has, so the same model is informative for one half of the disease and silent on the other. There is no naturally occurring veterinary counterpart.

Proposed experiments

Aged mouse carrying human LOXL1 risk haplotype under chronic ultraviolet and oxidative stress

xfs_humanized_loxl1_stress_model

Replace mouse Loxl1 regulatory sequence with the human risk haplotype including rs11638944 and the LOXL1-AS1 promoter region, age the animals, and apply chronic ultraviolet and oxidative stress to the anterior segment, scoring lens capsule and ciliary epithelium for fibrillar deposits by electron microscopy and LOXL1 immunolabelling. The human disease requires genotype, age and stress together; no existing model combines them.

Are the cardiovascular, cerebrovascular, hearing and pelvic-floor associations consequences of systemic elastosis, or confounding in an elderly, ultraviolet-exposed population?

KNOWLEDGE GAP OPEN xfs_systemic_associations_causal_or_confounded

Attached to

pathophysiology#Systemic Elastosis phenotypes#Abnormality of the cardiovascular system phenotypes#Sensorineural hearing impairment phenotypes#Pelvic organ prolapse

Deposits in vessel walls, heart and skin are real, and the meta-analytic association with vascular disease survives sensitivity analysis. But the studies are observational in people in their seventies, the cerebrovascular signal shows publication bias, the hearing series is a single uncontrolled clinic sample, and the prolapse association comes from diagnosis codes in a population database. No study has shown that the deposits impair vascular or cochlear function, and the earlier review of this disease was careful to call the associations preliminary. The distinction matters because a causal systemic disease would justify screening that an association does not.

Proposed experiments

Mendelian randomisation of systemic outcomes on exfoliation genotype

xfs_mendelian_randomization_systemic

Use the LOXL1 and other exfoliation risk alleles as instruments for cardiovascular, cerebrovascular, hearing and pelvic-floor outcomes in biobank data, within ancestry to respect the allele reversal. A genetic instrument is not confounded by age or sun exposure; an effect would make the systemic arm causal, and a null would argue for confounding.

Does lamina cribrosa elastosis make the exfoliation optic nerve more vulnerable to a given pressure, explaining the doubled conversion rate at matched pressure and the faster field loss?

KNOWLEDGE GAP OPEN xfs_lamina_cribrosa_and_pressure_vulnerability

Attached to

pathophysiology#Lamina Cribrosa Elastosis pathophysiology#Exfoliation Glaucoma Optic Neuropathy

Ocular hypertensives with the syndrome convert to glaucoma at twice the rate of controls matched for pressure, age and sex, so pressure alone does not explain the worse course. Site-specific elastosis of the lamina cribrosa, greater than in primary open-angle glaucoma, is the obvious structural candidate, but the histology comes from four optic nerve heads of two patients and no study has related laminar elastin content or biomechanics to progression. The alternative explanation, that undetected pressure fluctuation accounts for the excess risk, has not been excluded either.

Proposed experiments

In vivo lamina cribrosa biomechanics against progression rate

xfs_laminar_biomechanics_oct

Measure laminar depth, curvature and deformation under acute pressure change with optical coherence tomography in exfoliation glaucoma and pressure-matched primary open-angle glaucoma, and relate the measures to field progression over follow-up. A more deformable lamina at matched pressure in the exfoliation eyes would support the elastosis hypothesis; equal biomechanics would point back to pressure fluctuation.

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Pathophysiology

13

LOXL1 Susceptibility Genotype

The genetic root of the entry, and deliberately a susceptibility rather than a lesion. Two common coding variants in exon 1 of LOXL1 (rs1048661 p.Arg141Leu, rs3825942 p.Gly153Asp) and the intronic rs2165241 were found by the original Icelandic and Swedish genome-wide search to explain essentially all of the association at 15q24.1, with the highest-risk haplotype homozygous in a quarter of the population. The coding variants are not the functional ones: the risk allele at rs3825942 is reversed in black South Africans and at rs1048661 in Japanese and Koreans, which no simple protein-altering model survives, and the functional signal has since been located in noncoding regulatory sequence spanning introns 1 and 2, where rs11638944 alters RXR-alpha binding and LOXL1 splicing and where risk alleles modulate the promoter of the antisense lncRNA LOXL1-AS1. A rare coding allele, p.Phe407, is strongly protective. What the genotype changes is therefore how much LOXL1 a cell makes and how it responds to stress, not whether the enzyme works.

LOXL1 hgnc:6665

LOXL1 lysyl oxidase activity GO:0004720

Downstream

TGF-beta1 Excess and Oxidative Stress in the Anterior Segment The genotype couples to the cellular stress response through LOXL1-AS1: risk alleles alter the activity of the lncRNA promoter, and the lncRNA itself responds to oxidative and mechanical stress. This is the gene-environment junction of the disease, and it is an interaction claim rather than a claim that the genotype produces the stress.

Dysregulated LOXL1 Expression and Elastic Microfibril Cross-Linking Genotype sets the baseline level of LOXL1 in ocular tissue: expression falls by about a fifth per rs1048661 risk allele, and the intronic regulatory risk allele lowers LOXL1 mRNA in carriers.

Show evidence (4 references)

PMID:17690259 SUPPORT Human Clinical

"Two nonsynonymous SNPs in exon 1 of the gene LOXL1 explain the association, and the data suggest that they confer risk of XFG mainly through exfoliation syndrome (XFS)."

The founding genetic result: the LOXL1 association is with the syndrome, and glaucoma risk is carried through it. This is why the genotype sits at the head of the syndrome chain rather than at the glaucoma end.

PMID:17690259 SUPPORT Human Clinical

"About 25% of the general population is homozygous for the highest-risk haplotype, and their risk of suffering from XFG is more than 100 times that of individuals carrying only low-risk haplotypes."

A risk haplotype carried homozygously by a quarter of the population is a susceptibility allele by definition; the 100-fold relative risk is real but is relative to a rare low-risk group.

PMID:28534485 SUPPORT In Vitro

"We find that the rs11638944:C>G transversion exerts a cis-acting effect on the expression levels of LOXL1, mediated by differential binding of the transcription factor RXRα (retinoid X receptor alpha) and by modulating alternative splicing of LOXL1, eventually leading to reduced levels of LOXL1..."

The functional variant is regulatory and acts on LOXL1 expression and splicing, which is why this node is described as a change in how much LOXL1 a cell makes rather than a change in the enzyme.

+ 1 more reference

TGF-beta1 Excess and Oxidative Stress in the Anterior Segment

The milieu in which the matrix disorder unfolds, and the node where age and environment enter. The aqueous humour of affected eyes carries significantly more total and active TGF-beta1 than control eyes, while TGF-beta2 is unchanged; TGF-beta1, LTBP-1 and LTBP-2 are overexpressed in anterior-segment tissue, most strongly in the nonpigmented ciliary epithelium; antioxidant defence in the aqueous is reduced; and interleukin-6 and -8 run about threefold above controls. Ultraviolet light, hypoxia and homocysteine have each been proposed as drivers of this state, and the epidemiology of lifetime sunlight exposure supports at least the first. Latitude and reflected light are recorded as an environmental entry that acts on this node.

nonpigmented ciliary epithelial cell CL:0002304

TGF-beta1 signaling in the anterior segment GO:0007179 ↑ INCREASED oxidative stress in the aqueous humour and anterior segment GO:0006979 ↑ INCREASED

anterior segment of the eye UBERON:0001801

Downstream

Dysregulated LOXL1 Expression and Elastic Microfibril Cross-Linking TGF-beta1, oxidative stress, ultraviolet light and hypoxia each induce LOXL1 and the elastic proteins of exfoliation material in cultured fibroblasts, and TGF-beta1 with oxidative stress drives their assembly into PEX-like fibrils. This is the edge that turns a milieu into a matrix lesion.

Extracellular Chaperone Deficiency and Impaired Proteostasis TGF-beta1 represses clusterin in nonpigmented ciliary epithelial cells, so the same signal that drives matrix synthesis removes the chaperone that would keep the product soluble.

Show evidence (5 references)

PMID:11846508 SUPPORT Human Clinical

"Significantly increased concentrations of both total and active TGF-beta1 were measured in the aqueous humor of PEX eyes without and with glaucoma as compared to control eyes, whereas levels of TGF-beta2 were not significantly different."

The direct measurement behind the node, with the isoform specificity that makes TGF-beta1 rather than TGF-beta the claim.

PMID:11846508 SUPPORT Human Clinical

"The expression of TGF-beta1, LTBP-1, and LTBP-2, but not TGF-beta2, was markedly increased in anterior segment tissues of PEX eyes, particularly in the non-pigmented epithelium of the ciliary body, on both the mRNA and the protein level."

Localises the excess to the nonpigmented ciliary epithelium, which is also the cell type that produces exfoliation material and is bound on this node for that reason.

PMID:29401156 SUPPORT Other

"Furthermore, results from several studies find that the aqueous humor of exfoliation glaucoma patients exhibits a decreased antioxidant defense and increased oxidative stress systems."

The oxidative half of the node, from a review pooling the aqueous humour studies.

+ 2 more references

Dysregulated LOXL1 Expression and Elastic Microfibril Cross-Linking

LOXL1 is the cross-linking enzyme specifically required for elastic fibre formation and stabilisation, and in this disease it is regulated in the wrong direction at the wrong time. Ocular LOXL1 expression is significantly increased in early disease and decreased in advanced disease regardless of genotype, LOXL1 protein is a major component of the fibrillar aggregates in both intraocular and extraocular sites, and it co-localises with elastic fibre components on the fibrils. The working model is that excess LOXL1 during the initial fibrogenic phase participates in cross-linking elastic microfibrillar components (fibrillin-1, fibulins, tropoelastin) into abnormal aggregates, and that inadequate LOXL1 later promotes elastotic degeneration of existing elastic tissue. The N-terminal domain of LOXL1 is intrinsically disordered and misfolding-prone, with the risk residue 153 at the point of maximal disorder, which is the basis of the proteopathy reading of the disease.

LOXL1 hgnc:6665

elastic microfibril assembly and cross-linking GO:0048251 ↕ DYSREGULATED

LOXL1 lysyl oxidase activity GO:0004720 ↕ DYSREGULATED

Animal models

Loxl1-null mouse Mouse partially recapitulates Demonstrates that LOXL1 is required for elastic fibre maintenance and that its absence produces systemic elastic tissue failure, which is the biology this node rests on.

Downstream

Exfoliation Material Fibrillogenesis and Deposition Altered LOXL1 activation, processing or substrate specificity aggregates elastic fibre components into the characteristic fibrils; in culture, TGF-beta1 and oxidative stress produce LOXL1-containing microfibrillar networks that focally aggregate into PEX-like fibrils.

Systemic Elastosis The same elastic-matrix process runs in extraocular tissue: LOXL1 is a component of extraocular as well as intraocular aggregates, and deposits in visceral organs sit next to elastic and oxytalan fibres. What determines which organs deposit material, and why the eye is so much more affected, is not known.

Lamina Cribrosa Elastosis Marked, site-specific elastosis of the lamina cribrosa in exfoliation glaucoma, without typical exfoliation fibres, suggests abnormal regulation of elastin synthesis or degradation in the optic nerve. It is placed downstream of the elastic-fibre dysregulation node on that reading; the intermediates are not established.

Show evidence (4 references)

PMID:18974306 SUPPORT Human Clinical

"Irrespective of the individual genotype, LOXL1 expression was significantly increased in early PEX stages but was decreased in advanced stages both with and without glaucoma compared with controls, whereas LOX and LOXL2 showed no differences between groups."

The stage-dependent, isoform-specific expression change that makes this a dysregulation node rather than a simple loss or gain.

PMID:18974306 SUPPORT Human Clinical

"LOXL1 was also found to be a major component of fibrillar PEX aggregates in both intra- and extraocular locations and to co-localize with various elastic fiber components."

Places the enzyme physically in the lesion alongside its substrates, which is what a cross-linking pathogenesis predicts.

PMID:18809397 SUPPORT Other

"While increased levels of LOXL1 participate in the formation of abnormal PEX fiber aggregates in the initial phase of fibrogenesis, inadequate tissue levels may promote elastotic processes in advanced stages of the disease."

The two-phase model in the words of the group that proposed it: excess early, deficiency late.

+ 1 more reference

Extracellular Chaperone Deficiency and Impaired Proteostasis

The failure of the cell's protective machinery, the third leg of the consensus model. Clusterin, a highly efficient extracellular chaperone, is transcriptionally downregulated in every anterior-segment tissue of affected eyes and reduced in their aqueous humour, yet binds prominently to every deposit, which is what a chaperone overwhelmed by its substrate looks like. Inside the cell, patient-derived Tenon fibroblasts show defective lysosomal positioning, microtubule organisation, autophagic flux and mitochondrial health, and a substantial fraction of their LOXL1 is routed to autophagic degradation, which is why the disease has been proposed as an aggregopathy in the same family as the neurodegenerative proteinopathies.

nonpigmented ciliary epithelial cell CL:0002304 Tenon's capsule fibroblast CL:0000057

autophagic clearance GO:0006914 ↓ DECREASED

Downstream

Exfoliation Material Fibrillogenesis and Deposition Without adequate chaperoning and clearance, stress-induced matrix product aggregates and is stably deposited rather than kept soluble and removed.

Show evidence (3 references)

PMID:16639006 SUPPORT Human Clinical

"Real-time PCR and in situ hybridization displayed significant downregulation of clusterin mRNA in all anterior segment tissues of PEX eyes, irrespective of the presence or type of glaucoma, compared with normal and glaucomatous control eyes, whereas posterior segment tissues did not show any..."

The chaperone deficiency, measured in human tissue and confined to the anterior segment where the material forms.

PMID:16639006 SUPPORT Human Clinical

"Considering the known role of clusterin as a highly efficient extracellular chaperone, its deficiency in the anterior segment of PEX eyes may promote the stress-induced aggregation and stable deposition of the pathologic extracellular matrix product characteristic of PEX syndrome."

The interpretation that links chaperone loss to aggregation, in the authors' hedged form.

PMID:29547474 SUPPORT In Vitro

"We have documented defects in lysosomal positioning, microtubule organization, autophagy processing rate, and mitochondrial health."

The intracellular proteostasis defects, documented in patient-derived fibroblasts. IN_VITRO because the cells are cultured; the caveat that they come from trabeculectomy specimens of advanced disease is recorded in the knowledge-gap discussion.

Exfoliation Material Fibrillogenesis and Deposition

The lesion that gives the disease its name. Abnormal fibrillar extracellular material, made of microfibrils coated with amorphous material and containing fibrillin-1, LTBP-1 and -2, latent TGF-beta1, LOXL1, clusterin, fibulins and basement-membrane components, is produced by the pre-equatorial lens epithelium, the nonpigmented ciliary epithelium, the iris pigment epithelium, the corneal and trabecular endothelium and most iris stromal cell types, and accumulates on the anterior lens capsule in the classic pattern of a central disc, a clear intermediate zone and a granular peripheral ring, on the pupillary border, on the zonules and in the trabecular meshwork. It is insoluble and it is not cleared. Everything downstream is what this material does mechanically to the structures it lands on.

pre-equatorial lens epithelial cell CL:0002224 nonpigmented ciliary epithelial cell CL:0002304 iris pigment epithelial cell CL:0002565

abnormal extracellular matrix deposition GO:0030198 ↕ DYSREGULATED

anterior lens capsule UBERON:0001804 anterior segment of the eye UBERON:0001801

Animal models

Loxl1-null mouse Mouse fails to recapitulate The defining lesion of the human disease does not occur in the model.

Downstream

Zonular Degradation and Lens Instability Material produced by the nonpigmented ciliary epithelium and the lens epithelium intercalates at the zonular anchorage, infiltrates the bundles in the pars plicata and erupts through the capsular surface at the insertion, rupturing the zonules at all three levels.

Iris Pigment Epithelial Degeneration and Pigment Dispersion Deposition in and around the iris pigment epithelium at the pupillary margin degrades that layer and releases pigment into the anterior chamber.

Trabecular Meshwork Obstruction by Exfoliation Material and Pigment Material carried by aqueous flow, together with liberated pigment, deposits in the trabecular meshwork and obstructs the outflow pathway.

Pseudoexfoliation The deposits on the anterior lens capsule and pupillary border are the diagnostic sign itself.

Show evidence (4 references)

PMID:11166342 SUPPORT Other

"Exfoliation syndrome (XFS) is an age-related disease in which abnormal fibrillar extracellular material is produced and accumulates in many ocular tissues."

The definition of the disease is the definition of this node.

PMID:11166342 SUPPORT Other

"Regardless of etiology, typical exfoliation fibers have been demonstrated electron microscopically in close association with the pre-equatorial lens epithelium, the nonpigmented ciliary epithelium, the iris pigment epithelium, the corneal endothelium, the trabecular endothelium, and with almost..."

Names the producing cell types, which is why three of them are bound on this node.

PMID:11846508 SUPPORT Human Clinical

"Double immunolabeling revealed clear co-localization of LTBP-1 and -2 with latent TGF-beta1 and with fibrillin-1 on PEX fibrils."

The molecular composition of the fibrils, tying them to the TGF-beta1 and fibrillin biology upstream.

+ 1 more reference

Zonular Degradation and Lens Instability

The first of the three mechanical consequences. Exfoliation material separates the zonular bundles from the disrupted basement membrane of the nonpigmented epithelium at their origin, infiltrates them alongside the ciliary processes to the point of rupture, and lifts and ruptures the zonular lamella at the lens capsule; lysosomal enzymes within the aggregates indicate that proteolysis assists the disintegration. The lens then moves: phacodonesis, subluxation and frank dislocation follow, and the same weakness is why zonular dehiscence, capsular rupture and vitreous loss complicate cataract surgery many times more often than in other eyes. Zonular laxity also lets the lens-iris diaphragm move forward, which is the accepted basis for the angle-closure predisposition of this disease.

zonular fibres UBERON:0006762

Downstream

Phakodonesis A loose zonular apparatus lets the lens tremble with eye movement.

Lens subluxation Progressive zonular loss displaces the lens, spontaneously or late after cataract surgery as the capsular bag and implant dislocate together.

Angle closure glaucoma Exfoliation eyes are predisposed to angle closure; forward movement of a lens on lax zonules is the accepted explanation, though the cited review records the predisposition without demonstrating the intermediate step.

Show evidence (3 references)

PMID:7977599 SUPPORT Human Clinical

"In the pars plicata of the ciliary body, pseudoexfoliation material infiltrated the zonular bundles passing alongside the ciliary processes leading to zonular rupture."

The direct ultrastructural observation of material infiltrating and rupturing the zonules.

PMID:7977599 SUPPORT Human Clinical

"The immunohistochemical demonstration of lysosomal enzymes within pseudoexfoliation aggregates indicates that proteolytic mechanisms facilitate zonular disintegration."

Adds the proteolytic component of the disintegration.

PMID:11166342 SUPPORT Other

"The presence of XFS should alert the physician to the increased risks of intraocular surgery, most commonly zonular dehiscence, capsular rupture, and vitreous loss during cataract extraction."

The surgical consequence of the zonular weakness, which is the reason this node is clinically important out of proportion to its size.

Iris Pigment Epithelial Degeneration and Pigment Dispersion

The second mechanical consequence, and the point of contact with pigment dispersion syndrome. Deposition at the pupillary margin degrades the iris pigment epithelium of the sphincter region, producing peripupillary transillumination defects and releasing pigment that settles on the anterior chamber structures and, on gonioscopy, as patchy trabecular hyperpigmentation with a wavy pigment line anterior to Schwalbe's line (Sampaolesi line). Iris stromal and sphincter involvement is why the pupil dilates poorly, a small point with large surgical consequences. Unlike pigment dispersion syndrome the liberation is degenerative rather than mechanical, and the transillumination is peripupillary rather than mid-peripheral.

iris pigment epithelial cell CL:0002565

iris UBERON:0001769

Downstream

Iris transillumination defect Loss of the pigmented layer at the pupillary margin lets light through.

Poor pupillary dilation Degeneration of the iris sphincter region and stroma limits pharmacological mydriasis.

Trabecular Meshwork Obstruction by Exfoliation Material and Pigment Liberated pigment is carried by the aqueous into the meshwork, adding a second particulate load to the exfoliation material already there.

Pigment deposition in the trabecular meshwork The gonioscopic sign of the dispersed pigment, kept separate from the outflow node because pigmentation of the angle is present in eyes with normal pressure.

Show evidence (2 references)

PMID:11166342 SUPPORT Other

"Pigment loss from the iris sphincter region and its deposition on anterior chamber structures is a hallmark of XFS."

Both halves of the node in one sentence: the loss at the sphincter and the deposition elsewhere.

PMID:38304644 SUPPORT Other

"Symptoms of PEX include elevated intraocular pressure, peripapillary transillumination deficiencies, potential glaucomatous optic nerve damage, poor dilatation, Sampaolesi line, and fibrillar white flaky deposits along the pupillary border."

Lists the transillumination defects, poor dilatation and Sampaolesi line that this node produces. Quoted verbatim, including the source's "peripapillary" where peripupillary is meant.

Trabecular Meshwork Obstruction by Exfoliation Material and Pigment

The third mechanical consequence and the one that matters most. Exfoliation material and iris pigment carried by aqueous flow deposit in the trabecular meshwork and juxtacanalicular tissue, physically obstruct the outflow pathway and raise resistance; in older eyes the age-related narrowing of the outflow channels to the inner wall of Schlemm's canal makes the load harder to clear. This is the disorder-specific substitution into the glaucoma module: the trabecular dysfunction here is obstruction by deposited material rather than the intrinsic juxtacanalicular pathology of primary open-angle glaucoma, and unlike pigment dispersion syndrome the material is not phagocytosable debris but insoluble cross-linked fibrils.

trabecular meshwork cell CL:0002367

trabecular extracellular matrix obstruction GO:0030198 ↕ DYSREGULATED

trabecular meshwork UBERON:0005969

Downstream

Elevated Intraocular Pressure Rising outflow resistance raises intraocular pressure. As in pigment dispersion, the edge fires only in a subset of eyes; a heavily loaded angle with normal pressure is common.

Show evidence (2 references)

PMID:29401156 SUPPORT Other

"The primary consequence of the presence of this material in the eye is an elevation of intraocular pressure (IOP), most likely due to the release of XFM and iris pigment particles and their deposition in the trabecular meshwork (TM), leading to physical obstruction of the aqueous humor outflow..."

The mechanism of the node in full: material plus pigment, deposited in the meshwork, physically obstructing outflow.

PMID:28534485 SUPPORT Other

"It is thought to be caused by the obstruction of the aqueous humour outflow pathways because of the deposition of extracellular protein aggregates leading to intraocular pressure elevation and subsequent glaucomatous optic nerve damage."

The same chain stated in the introduction of the functional-genetics paper; OTHER because the sentence is background synthesis rather than a result of the study.

Elevated Intraocular Pressure

Sustained rise in intraocular pressure as outflow resistance outstrips compensation. The pressure in exfoliation eyes is characteristically higher, more labile and more prone to spikes than in primary open-angle glaucoma, so that a single office reading underestimates the exposure; in newly diagnosed high-pressure exfoliation patients the untreated 24-hour mean pressure sits above 30 mmHg. It is the node that carries the chain to the optic nerve and the only one current treatment acts on.

Animal models

Loxl1-null mouse Mouse fails to recapitulate Pressure stays normal for at least a year, so the model has no glaucoma arm.

Downstream

Retinal Ganglion Cell Apoptosis Sustained pressure elevation stresses the optic nerve head and drives ganglion cell death, the conserved module step.

Ocular hypertension The measurable clinical sign of this node.

Show evidence (3 references)

PMID:18028119 SUPPORT Human Clinical

"Eyes with PEX were found to have higher intraocular pressure (IOP) than eyes without PEX (p < 0.05)."

Population-based confirmation that the syndrome, before any glaucoma diagnosis, raises pressure.

PMID:23686322 SUPPORT Human Clinical

"At baseline, mean untreated 24-h IOP was 31.1 mm Hg."

The magnitude of untreated pressure in the high-pressure exfoliation population, from a 24-hour curve rather than a single reading.

PMID:39458082 SUPPORT Other

"Exfoliation glaucoma presents a risk of higher IOP and a more rapid progression of visual field defects"

The higher-pressure, faster-course character of this glaucoma, stated as background in a surgical series; OTHER because it is synthesis rather than a result.

Lamina Cribrosa Elastosis

The node that is specific to this disease within the glaucoma arm. The connective tissue of the lamina cribrosa in exfoliation glaucoma shows marked, widespread elastosis, with large irregular elastin-positive aggregates interspersed with microfibrils and without typical exfoliation fibres, and the elastosis is greater than in primary open-angle glaucoma and absent from the retrolaminar nerve. It is the leading structural explanation for why these optic nerves progress faster at a given pressure, but that step, from elastotic lamina to heightened pressure vulnerability, is an inference and is curated as one.

lamina cribrosa UBERON:0035966

Downstream

Retinal Ganglion Cell Apoptosis An elastotic, mechanically abnormal lamina is proposed to transmit pressure to the ganglion cell axons less protectively, contributing to the faster course. Hypothesis, not demonstration; the knowledge gap below records it.

Show evidence (2 references)

PMID:7777294 SUPPORT Human Clinical

"In all eyes with pseudoexfoliation and glaucoma, there was marked and widespread elastosis in the connective tissue of the lamina cribrosa."

The observation that defines the node.

PMID:7777294 SUPPORT Human Clinical

"In contrast, there were less elastotic fibers in the lamina cribrosa from patients with primary open-angle glaucoma compared with pseudoexfoliation glaucoma."

The comparison with primary open-angle glaucoma that makes this a disease-specific finding rather than a generic glaucomatous change.

Retinal Ganglion Cell Apoptosis

Pressure-related stress at the optic nerve head drives apoptotic loss of retinal ganglion cells, the conserved effector step of every glaucoma. The entry adds nothing disease-specific at this node beyond the two upstream inputs, higher and more labile pressure and an elastotic lamina; the cellular biology is the module's.

retinal ganglion cell CL:0000740

retinal ganglion cell apoptosis GO:0051402 ↑ INCREASED

Downstream

Exfoliation Glaucoma Optic Neuropathy Cumulative ganglion cell and axon loss produces the disc cupping and field loss that make the diagnosis.

Show evidence (1 reference)

PMID:28534485 SUPPORT Other

"It represents a neurodegenerative disease complex comprising heterogeneous subtypes that share a common pathogenic pathway, that is, progressive loss of retinal ganglion cells and optic nerve axons resulting in visual field defects."

The shared final pathway of glaucoma, of which exfoliation glaucoma is named as the frequent, progressive subtype. OTHER because the sentence is background synthesis.

Exfoliation Glaucoma Optic Neuropathy

The point at which the diagnosis changes name. Exfoliation glaucoma is the commonest identifiable cause of secondary open-angle glaucoma worldwide, accounting for roughly a quarter of open-angle glaucoma, and it is a worse disease than primary open-angle glaucoma: pressures are higher, medical control is poorer, laser and surgery are needed more often, and the visual field deteriorates faster. Conversion is substantial but far from universal, which is what makes the syndrome a risk state rather than a glaucoma: about 44% of newly diagnosed patients in a community cohort reached treatment within 15 years, and among ocular hypertensives the syndrome doubled the conversion rate to perimetric glaucoma at matched pressure.

retinal ganglion cell CL:0000740

Downstream

Open angle glaucoma Glaucomatous optic neuropathy with an open angle is the diagnostic threshold, not a separate biological step.

Visual field defect Ganglion cell loss produces the characteristic field defects, which progress faster here than in primary open-angle glaucoma.

Visual impairment Advanced, often late-recognised optic neuropathy is the main route to irreversible visual loss in this disease.

Show evidence (4 references)

PMID:15745763 SUPPORT Human Clinical

"After a mean of 8.7 years (range: 6.3-11.4), 54 of 98 patients (55.1%) with pseudoexfoliation at the baseline examination and 27 of 98 patients (27.6%) without pseudoexfoliation had developed glaucoma."

At matched pressure, age and sex, the syndrome doubled conversion to glaucoma, which is the strongest evidence that something beyond pressure, such as the elastotic lamina, is at work.

PMID:17986292 SUPPORT Human Clinical

"PEX increased the risk of glaucoma four fold in both sexes."

The population-level risk, from a 21-year prospective cohort.

PMID:28553957 SUPPORT Other

"Exfoliation glaucoma (XFG) has a worse prognosis than other major types of glaucoma, and it is often resistant to intraocular pressure-lowering medical treatment"

The worse prognosis and poorer medical response that distinguish this glaucoma; OTHER because the sentence is the paper's background synthesis.

+ 1 more reference

Systemic Elastosis

Aggregates consistent with exfoliation material are present in the lung, heart, liver, gallbladder and skin of affected people, in fibrovascular septa adjacent to elastic and oxytalan fibres, staining for elastin and amyloid P like the ocular deposits. This is the histological basis for calling the syndrome systemic, and it explains why the systemic associations were looked for. Whether it produces disease outside the eye is a different question: the cardiovascular, cerebrovascular, hearing and pelvic-floor associations recorded below are epidemiological, are susceptible to the confounding of an elderly population, and are curated as associations with the gap left open.

skin UBERON:0002097 heart UBERON:0000948 lung UBERON:0002048

Downstream

Abnormality of the cardiovascular system Meta-analysis finds a 1.6-fold odds of cardiovascular disease with the syndrome. The edge is drawn because vascular elastic tissue is a site of deposition, but no intermediate has been demonstrated and confounding is not excluded.

Sensorineural hearing impairment Hearing thresholds exceed age norms in most affected patients; the proposed intermediate is deposition in the inner ear, which has not been shown.

Pelvic organ prolapse The most mechanistically coherent association, because Loxl1-null mice develop pelvic organ prolapse from failed elastic fibre maintenance; in humans it is a population-database association only.

Show evidence (2 references)

PMID:1463419 SUPPORT Human Clinical

"Aggregates consistent with pseudoexfoliative material were present in the lung, heart, liver, and gallbladder, in addition to the classic intraocular sites."

The autopsy demonstration of visceral deposits, a single case but the one that established the systemic concept.

PMID:26307087 SUPPORT Other

"Exfoliation syndrome (XFS) is a common, age-related, systemic fibrillinopathy."

The systemic framing as now standard; OTHER because the sentence is the paper's opening synthesis rather than its result.

⬡

Pathograph

Use the checkboxes to hide or show graph categories. Hover nodes for evidence and cross-linked metadata.

●

Phenotypes

15

Cardiovascular 1

Abnormality of the cardiovascular system HP:0001626

Show evidence (3 references)

PMID:30119791 SUPPORT Human Clinical

"Twenty studies enrolling 9583 individuals with PEX evaluated CVD, providing a summary odds ratio (OR) of 1.61 (95% CI 1.37-1.90)."

The pooled association for cardiovascular disease.

PMID:30119791 SUPPORT Human Clinical

"Analysis for publication bias with the Egger's test was not significant for studies reporting CVD and AVE (p = 0.92 and 0.64, respectively) but was significant for CVA (p = 0.03)."

The publication-bias caveat that keeps this an association rather than a finding; cited so the weakness of the cerebrovascular signal is on the record.

PMID:11166342 SUPPORT Other

"XFS is now suspected to be a systemic disorder and has been associated preliminarily with transient ischemic attacks, stroke, systemic hypertension, and myocardial infarction."

The associations as first described, in language ("suspected", "preliminarily") that this entry keeps.

Ear 1

Sensorineural hearing impairment HP:0000407

Show evidence (2 references)

PMID:12032714 SUPPORT Human Clinical

"A large proportion of patients with PXF have sensorineural hearing loss in comparison to age-matched controls, regardless of whether or not there is associated glaucoma."

The finding as the authors state it.

PMID:12032714 SUPPORT Human Clinical

"There was no significant difference between the proportion of ears with HTL1,2,3 higher than the ISO 7029 median AAHL1,2,3 on the same side as eyes without PXF, with PXF but not glaucoma and with PXF and glaucoma, in either the male or female groups."

Hearing loss did not track the affected eye, which argues for a systemic rather than a local process, and equally leaves confounding open.

Eye 11

Pseudoexfoliation OBLIGATE HP:0012627

Show evidence (2 references)

PMID:11166342 SUPPORT Other

"Deposits of white material on the anterior lens surface are the most consistent and important diagnostic feature of XFS."

Establishes the deposits as the defining, diagnostic sign, which is the basis for the OBLIGATE frequency.

PMID:11166342 SUPPORT Other

"The classic pattern consists of three distinct zones that become visible when the pupil is fully dilated."

The three-zone pattern and the need for dilation to see it.

Iris transillumination defect HP:0012805

Show evidence (2 references)

PMID:38304644 SUPPORT Other

"Symptoms of PEX include elevated intraocular pressure, peripapillary transillumination deficiencies, potential glaucomatous optic nerve damage, poor dilatation, Sampaolesi line, and fibrillar white flaky deposits along the pupillary border."

Names transillumination defects among the cardinal signs. Quoted verbatim; the source writes "peripapillary" where peripupillary is meant.

PMID:11166342 SUPPORT Other

"Pigment loss from the iris sphincter region and its deposition on anterior chamber structures is a hallmark of XFS."

The pigment loss at the sphincter region is what transilluminates.

Pigment deposition in the trabecular meshwork HP:0012631

Show evidence (1 reference)

PMID:38304644 SUPPORT Other

"Symptoms of PEX include elevated intraocular pressure, peripapillary transillumination deficiencies, potential glaucomatous optic nerve damage, poor dilatation, Sampaolesi line, and fibrillar white flaky deposits along the pupillary border."

Names the Sampaolesi line, the gonioscopic signature of the dispersed pigment.

Ocular hypertension HP:0007906

Show evidence (2 references)

PMID:18028119 SUPPORT Human Clinical

"Eyes with PEX were found to have higher intraocular pressure (IOP) than eyes without PEX (p < 0.05)."

Population-based association of the syndrome with higher pressure.

PMID:17224761 SUPPORT Human Clinical

"The strongest risk factors for converting to therapy were IOP at initial diagnosis of PEX and bilateral involvement."

Pressure at diagnosis is the strongest predictor of needing treatment, which is why this phenotype is the one to follow.

Open angle glaucoma FREQUENT HP:0012108

Show evidence (4 references)

PMID:23157966 SUPPORT Other

"Pseudoexfoliation is the most common cause of secondary open-angle glaucoma (pseudoexfoliation glaucoma, PXG) worldwide."

Defines the phenotype as a secondary open-angle glaucoma and gives its global standing.

PMID:35348588 SUPPORT Other

"Secondary open-angle glaucoma, which occurs in up to 44% of PEX-affected eyes"

The proportion of affected eyes that develop glaucoma, supporting the FREQUENT band (30-79%). OTHER because it is the paper's background synthesis, not its result.

PMID:17224761 SUPPORT Human Clinical

"In the remaining PEX patients, the probability of being placed on therapy was 44% at 15 years."

A community-based conversion figure consistent with the band; the endpoint is treatment for glaucoma or treated ocular hypertension, so it slightly overstates glaucoma itself.

+ 1 more reference

Angle closure glaucoma HP:0012109

Show evidence (1 reference)

PMID:11166342 SUPPORT Other

"Patients with XFS are also predisposed to develop angle-closure glaucoma, and glaucoma in XFS has a more serious clinical course and worse prognosis than primary open-angle glaucoma."

Establishes the angle-closure predisposition.

Visual field defect Glaucomatous visual field defect HP:0007854

Show evidence (2 references)

PMID:39458082 SUPPORT Other

"Exfoliation glaucoma presents a risk of higher IOP and a more rapid progression of visual field defects"

Names the faster field progression that characterises this glaucoma.

PMID:28534485 SUPPORT Other

"It represents a neurodegenerative disease complex comprising heterogeneous subtypes that share a common pathogenic pathway, that is, progressive loss of retinal ganglion cells and optic nerve axons resulting in visual field defects."

Field defects as the functional consequence of ganglion cell loss.

Visual impairment HP:0000505

Show evidence (1 reference)

PMID:28553957 SUPPORT Human Clinical

"Exfoliation syndrome (XFS) is the most common known risk factor for secondary glaucoma and a major cause of blindness worldwide."

The blindness burden, stated by the largest genetic study of the disease.

Phakodonesis HP:0012629

Show evidence (1 reference)

PMID:7977599 SUPPORT Human Clinical

"A weak zonular apparatus has been postulated to account for the high incidence of phacodonesis, lens dislocation, and vitreous complications during extracapsular cataract surgery in eyes with pseudoexfoliation syndrome."

Names phacodonesis as a frequent consequence of the zonular weakness the paper then demonstrates.

Lens subluxation HP:0001132

Show evidence (2 references)

PMID:7977599 SUPPORT Human Clinical

"A weak zonular apparatus has been postulated to account for the high incidence of phacodonesis, lens dislocation, and vitreous complications during extracapsular cataract surgery in eyes with pseudoexfoliation syndrome."

Names lens dislocation among the consequences of zonular weakness.

PMID:35348588 SUPPORT Other

"Cataract surgery in PEX is associated with higher intraoperative complication rates owing to zonular instability, lens dislocation, impaired pupillary dilation, and increased postoperative complication rates owing to corneal decompensation, IOP spikes, and posterior capsular opacification"

Lens dislocation among the surgical complications attributed to zonular instability; OTHER because it is the paper's background synthesis.

Cataract HP:0000518

Show evidence (2 references)

PMID:19465298 SUPPORT Other

"Cataracts occur with increased frequency in PXF eyes, and surgery is potentially complicated by the presence of small pupils and zonule laxity and significantly affects IOP in these eyes."

The increased cataract frequency and its surgical implications.

PMID:35348588 SUPPORT Other

"Australian epidemiological data demonstrating that PEX-affected eyes have twice the prevalence of nuclear cataract"

The quantitative excess of nuclear cataract; OTHER because the sentence is the paper's background synthesis of a cited cohort.

Genitourinary 1

Pelvic organ prolapse HP:0031607

Show evidence (2 references)

PMID:27632406 SUPPORT Human Clinical

"Pelvic organ prolapse was associated with a 1.56-fold increased risk of exfoliation syndrome in Medicare beneficiaries (OR, 1.56; 95% CI, 1.42-1.72) in substudy A."

The cross-sectional association.

PMID:27632406 SUPPORT Human Clinical

"Systemic conditions with altered ECM metabolism, such as pelvic organ prolapse, may share common biological pathways with exfoliation syndrome."

The authors' interpretation, hedged as a shared pathway rather than a cause.

Other 1

Poor pupillary dilation

Left unbound. HPO has Mydriasis (HP:0011499) and Miosis (HP:0000616), but no term for impaired pharmacological dilation of an otherwise normal-sized pupil, and Abnormal pupil morphology (HP:0000615) would misdescribe a functional finding.

Show evidence (2 references)

PMID:38304644 SUPPORT Other

"Symptoms of PEX include elevated intraocular pressure, peripapillary transillumination deficiencies, potential glaucomatous optic nerve damage, poor dilatation, Sampaolesi line, and fibrillar white flaky deposits along the pupillary border."

Names poor dilatation among the cardinal signs.

PMID:19465298 SUPPORT Other

"Cataracts occur with increased frequency in PXF eyes, and surgery is potentially complicated by the presence of small pupils and zonule laxity and significantly affects IOP in these eyes."

The surgical consequence of the small pupil.

🧬

Genetic Associations

4

LOXL1

Gene: LOXL1 hgnc:6665 relationship_type: SUSCEPTIBILITY

Show evidence (6 references)

PMID:17690259 SUPPORT Human Clinical

"Two nonsynonymous SNPs in exon 1 of the gene LOXL1 explain the association, and the data suggest that they confer risk of XFG mainly through exfoliation syndrome (XFS)."

The original association.

PMID:20431720 SUPPORT Human Clinical

"The A allele of rs3825942 (encoding aspartic acid) was the risk allele, in sharp contrast to the G allele (encoding glycine) reported in multiple other populations."

The allele reversal, which is the single strongest argument that the coding variants tag rather than cause.

PMID:26404116 SUPPORT Human Clinical

"Rs3825942 (G) was an at risk allele for PEX/PEXG in Caucasians, Japanese, Koreans, Chinese, South Asians, and Middle Easterners, but protective in Black South Africans (OR = 0.10, 95%CI:0.06-0.16)."

The reversal confirmed across 39 cohorts by meta-analysis.

+ 3 more references

CACNA1A

Gene: CACNA1A hgnc:1388 relationship_type: SUSCEPTIBILITY

Show evidence (1 reference)

PMID:28553957 SUPPORT Human Clinical

"Variants in two genes, LOXL1 and CACNA1A, have previously been associated with XFS."

Names CACNA1A as the second established locus.

Additional genome-wide susceptibility loci

relationship_type: SUSCEPTIBILITY

Show evidence (1 reference)

PMID:28553957 SUPPORT Human Clinical

"We identified association signals at 13q12 (POMP), 11q23.3 (TMEM136), 6p21 (AGPAT1), 3p24 (RBMS3) and 5q23 (near SEMA6A)."

The five loci, reported as regions with the nearest gene.

CYP39A1

Gene: CYP39A1 hgnc:17449 relationship_type: RISK_FACTOR

Show evidence (2 references)

PMID:33620406 SUPPORT Human Clinical

"In the discovery cohort, persons with exfoliation syndrome, compared with those without exfoliation syndrome, were significantly more likely to carry damaging CYP39A1 variants (1.3% vs 0.30%, respectively; odds ratio, 3.55 [95% CI, 2.07-6.10]; P = 6.1 × 10-7)."

The discovery association, with the carrier frequencies that show how small the affected minority is.

PMID:33620406 SUPPORT Human Clinical

"CYP39A1 transcript expression was 47% lower (95% CI, 30%-64% lower; P < .001) in ciliary body tissues from individuals with exfoliation syndrome compared with individuals without exfoliation syndrome."

Reduced expression in the tissue that produces exfoliation material, which is what connects the genetic finding to the mechanism.

💊

Medical Actions

4

Topical Intraocular Pressure Lowering Pharmacotherapy

Action: Pharmacotherapy NCIT:C15986

Agent: latanoprost CHEBI:6384 bimatoprost CHEBI:51230 timolol CHEBI:39465

Platform: Small molecule

The pharmacological arm treats pressure, not material: nothing removes deposited exfoliation material or restores the meshwork, so this is the same topical repertoire as other open-angle glaucomas, applied earlier and harder because the pressures are higher and more labile. Prostaglandin analogues are first line; in newly diagnosed high-pressure exfoliation patients a bimatoprost-timolol fixed combination lowered 24-hour pressure more than latanoprost alone, which is the trial evidence that a single agent is often not enough here. Medical control fails more often than in primary open-angle glaucoma, so laser and surgery are reached sooner.

Mechanism Target:

INHIBITS Elevated Intraocular Pressure — Lowers pressure by increasing uveoscleral outflow or reducing aqueous production, acting around the obstructed meshwork rather than on it.

Show evidence (1 reference)

PMID:23686322 SUPPORT Human Clinical

"Mean 24-h IOP with BTFC was significantly lower than with latanoprost (18.9 vs 21.2 mm Hg; p<0.001)."

Both regimens lowered a baseline 24-hour mean of 31.1 mmHg, and the combination lowered it further, which is the pressure effect this edge records.

Show evidence (2 references)

PMID:23686322 SUPPORT Human Clinical

"As first choice therapy in high-pressure, at-risk exfoliation patients, BTFC controlled mean 24-h IOP significantly better than latanoprost monotherapy."

A randomised crossover comparison in the exfoliation population specifically.

PMID:28553957 SUPPORT Other

"Exfoliation glaucoma (XFG) has a worse prognosis than other major types of glaucoma, and it is often resistant to intraocular pressure-lowering medical treatment"

The limitation of the pharmacological arm in this disease.

Selective Laser Trabeculoplasty

Action: selective laser trabeculoplasty Ontology label: Laser Therapy NCIT:C15466

Platform: Surgery

Laser applied to the trabecular meshwork, mechanistically well suited to this disease because it targets pigmented trabecular cells and the exfoliation meshwork is heavily pigmented. In medically uncontrolled exfoliation glaucoma it succeeded in about two fifths of eyes at one year and was safe; the effect wanes with time and, as in pigment dispersion, a heavily pigmented angle can spike after treatment. A systematic review of the randomised trials found no technique clearly superior to another.

Mechanism Target:

INHIBITS Trabecular Meshwork Obstruction by Exfoliation Material and Pigment — Acts on the loaded meshwork itself, through a route (biological remodelling of trabecular cells rather than removal of material) that is not settled.

Show evidence (1 reference)

PMID:34634862 SUPPORT Human Clinical

"Selective laser trabeculoplasty (SLT) uses a 532-nm Q-switched, frequency-doubled Nd:YAG laser with nanosecond pulse duration, which selectively targets the pigmented trabecular meshwork without collateral thermal damage to the adjacent non-pigmented trabecular meshwork and underlying trabecular beams"

The laser targets pigmented meshwork specifically, which is why it is aimed at this node and why it suits a pigmented exfoliation angle.

Show evidence (2 references)

PMID:34634862 SUPPORT Human Clinical

"Based on the Kaplan-Meier survival analysis, the treatment success rate at 12 months after SLT was 41.9% (18 eyes)."

The one-year success rate in medically refractory exfoliation glaucoma, modest and honestly reported.

PMID:33564134 SUPPORT Human Clinical

"There are no apparent differences in efficacy and safety, although with large uncertainty, between surgical or laser techniques for PXFG."

The systematic-review verdict that no laser or surgical technique has demonstrated superiority in this disease.

Cataract Surgery with Zonular and Pupil Support

Action: phacoemulsification with capsular tension ring or iris expansion device as required Ontology label: Cataract Surgery NCIT:C157809

Platform: Surgery

Phacoemulsification in an exfoliation eye is a different operation: the pupil is small, the zonules are weak, and zonular dehiscence, capsular rupture and vitreous loss are the classic complications. In a 4,535-eye registry, zonular weakness needing a capsular tension ring occurred 30 times and posterior capsular rupture 13 times more often than in other eyes, and the procedure cost 1.4 times as much. Iris expansion devices, capsular tension rings or hooks, and secure lens fixation are the countermeasures; late in-the-bag lens dislocation remains a risk for years. Lens extraction also modestly lowers pressure. The surgery addresses the cataract and, through the precautions, the zonular phenotype; it does not act on any mechanism node.

Target Phenotypes: Cataract HP:0000518

Show evidence (3 references)

PMID:38202045 SUPPORT Human Clinical

"Zonular weakness requiring the use of a capsular tension ring (CTR) and posterior capsular rupture occurred 30 and 13 times more often, respectively, in the PEX group."

The registry-scale quantification of the surgical risk and of the use of capsular tension rings to meet it.

PMID:19465298 SUPPORT Other

"Preoperative evaluation and the options for intraoperative management of cataract are presented with recommendations for the use of adjunctive pupil and zonule support devices."

The surgical recommendation for pupil and zonule support devices.

PMID:11166342 SUPPORT Other

"The presence of XFS should alert the physician to the increased risks of intraocular surgery, most commonly zonular dehiscence, capsular rupture, and vitreous loss during cataract extraction."

The complications the precautions exist to prevent.

Filtration Surgery

Action: trabeculectomy Ontology label: Surgical Construction of Filtration Bleb NCIT:C220170

Platform: Surgery

Trabeculectomy, the reference operation when medication and laser fail, which happens more often in this glaucoma than in primary open-angle glaucoma. Subconjunctival microshunts and other minimally invasive procedures are alternatives; in one exfoliation series a microshunt gave roughly 50% success at a year with a 30% reoperation rate, and the systematic review of randomised trials could not justify preferring any one technique. Filtration bypasses the obstructed meshwork rather than clearing it.

Mechanism Target:

BYPASSES Elevated Intraocular Pressure — Creates an alternative drainage route past the obstructed trabecular meshwork, lowering pressure without acting on the material.

Show evidence (1 reference)

PMID:39458082 SUPPORT Human Clinical

"The postoperative outcomes of the PreserFlo MicroShunt in Asian patients with exfoliation glaucoma demonstrated an approximate 50% success rate at both 24 and 48 weeks, with a reoperation rate of approximately 30%."

A subconjunctival filtration device lowers pressure in this population, with the sobering success and reoperation figures that a reader should see beside the claim.

Show evidence (2 references)

PMID:33564134 SUPPORT Human Clinical

"Based on the low-quality evidence from the six studies included in this review, it is not possible to justify the preferential use of non-penetrating surgery, MIGS or trabecular aspiration (with or without cataract surgery) in PXFG."

The state of the comparative evidence among surgical options.

PMID:28553957 SUPPORT Other

"Exfoliation glaucoma (XFG) has a worse prognosis than other major types of glaucoma, and it is often resistant to intraocular pressure-lowering medical treatment"

Why surgery is reached more often in this glaucoma.

🌍

Environmental Factors

1

Lifetime solar exposure and reflected light

Lifetime residential latitude away from the equator, hours spent outdoors in summer, and work over water or snow are each associated with the syndrome in a clinic-based case-control study in the United States and Israel, and sunglass use was protective in the United States arm. A history of non-melanoma skin cancer, as a marker of cumulative ultraviolet exposure, carried a 40% higher risk of exfoliation glaucoma in 120,000 health-professional cohort participants. Together with the ability of ultraviolet light to induce LOXL1 and elastic proteins in culture, this is the best-supported environmental contributor, though a gene-environment interaction with LOXL1 has been proposed and not confirmed.

Show evidence (4 references)

PMID:25188364 SUPPORT Human Clinical

"In multivariable analyses, each degree of weighted lifetime average residential latitude away from the equator was associated with 11% increased odds of XFS (pooled odds ratio [OR], 1.11; 95% CI, 1.05-1.17; P < .001)."

The latitude gradient, with its effect size.

PMID:25188364 SUPPORT Human Clinical

"The association with work over snow or water and the lack of association with brimmed hat wear suggests that ocular exposure to light from reflective surfaces may be an important type of exposure in XFS etiology."

The specific exposure the pattern points to: light reaching the eye from below, which a hat does not block and sunglasses do.

PMID:32487970 SUPPORT Human Clinical

"In multivariable-adjusted analyses, we observed a 40% higher XFG risk with any NMSC history (MVRR=1.40; 95% CI=1.08-1.82); the association was observed even with 4 and 8-year lags in NMSC history."

Prospective cohort support using a proxy for cumulative ultraviolet exposure.

+ 1 more reference

Mechanism Target:

PREDISPOSES TGF-beta1 Excess and Oxidative Stress in the Anterior Segment — Ultraviolet light induces LOXL1 and elastic fibre proteins in cultured fibroblasts alongside TGF-beta1 and oxidative stress, and reflected light reaching the eye is the exposure the epidemiology implicates; the in vivo route from light to the anterior-segment stress milieu is not demonstrated, hence PREDISPOSES rather than TRIGGERS.

Show evidence (1 reference)

PMID:21948647 SUPPORT INDIRECT In Vitro

"Treatment of fibroblasts with TGF-β1, oxidative stress, UV light, and hypoxia induced a significant increase in expression levels of LOXL1 and elastic proteins, whereas the effect of IL-6 was limited to induction of elastic constituents."

Ultraviolet light acts on the same fibrogenic programme as the stress milieu; INDIRECT because the experiment is in culture and the exposure is applied to fibroblasts rather than to the eye.

🔬

Diagnosis

1

Dilated slit-lamp examination

Diagnosis is clinical. The deposits on the anterior lens capsule and pupillary border are the most consistent and important diagnostic feature, and the classic three-zone capsular pattern is seen only through a fully dilated pupil, so the examination must be repeated after dilation and should note pupil size, iris transillumination, phacodonesis and lens position. Tonometry, gonioscopy for angle pigmentation and Sampaolesi line, and disc, nerve fibre layer and field assessment stage the glaucoma. There is no laboratory, genetic or imaging test for the syndrome; LOXL1 genotyping has no diagnostic role because the risk alleles are carried by most unaffected people.

Show evidence (2 references)

PMID:11166342 SUPPORT Other

"Deposits of white material on the anterior lens surface are the most consistent and important diagnostic feature of XFS."

The diagnostic sign.

PMID:11166342 SUPPORT Other

"The classic pattern consists of three distinct zones that become visible when the pupil is fully dilated."

Why dilation is required.

📊

Prevalence

3

Reykjavik, Iceland, adults aged 50 and over

Point Prevalence 10700.0 per 100,000 >1 in 1,000

10.7% of a random population sample aged 50 or more had exfoliation in at least one eye, rising from 2.5% at 50-59 to 40.6% at 80 and over, with women more often affected than men. Iceland is a high-prevalence population; prevalence worldwide ranges from below 1% to above 20% by age, ancestry, latitude and examination technique.

Show evidence (2 references)

PMID:18028119 SUPPORT Human Clinical

"In all, 108 (10.7%) persons were found to have PEX in at least one eye."

The population-based prevalence figure recorded.

PMID:18028119 SUPPORT Human Clinical

"Prevalence increased from 2.5% in those aged 50-59 years to 40.6% in those aged > or = 80 years."

The age gradient, which is steeper than for almost any other eye disease and is why age is the dominant risk factor.

Northern Sweden (Skellefteå), 1915 birth cohort followed from age 66 to 87

Point Prevalence 23000.0 per 100,000 (20000.0–26000.0) >1 in 1,000

23% (95% CI 20-26) at 66 years, rising to 61% at 87 in the same cohort; annual incidence 1.8%. The 66-year figure is recorded as the rate; the 87-year figure shows what a lifetime of exposure does in a Scandinavian population.

Show evidence (2 references)

PMID:17986292 SUPPORT Human Clinical

"The prevalence of PEX increased from 23%[95% confidence interval (CI): 20-26] at 66 years of age to 61% (CI 50-71) at 87 years."

The prospective prevalence figures recorded.

PMID:17986292 SUPPORT Human Clinical

"The annual incidence of PEX was 1.8% (CI 1.3-2.4)."

The incidence in the same cohort, for context.

Worldwide

Cases In Literature Common

An estimated 60-70 million people affected worldwide, per the 2017 international genetic study; the report used for this entry cites a higher estimate of about 80 million. Prevalence varies widely and no single global rate is meaningful, so the qualitative class is used.

Show evidence (1 reference)

PMID:28553957 SUPPORT Other

"This disease is common in many populations, with an estimated 60–70 million patients affected"

The global case estimate; OTHER because it is the paper's background synthesis of earlier surveys.

🔀

Differential Diagnoses

4

Conditions with similar clinical presentations that must be differentiated from Exfoliation Syndrome:

Pigment dispersion syndrome

Overlapping Features The other pigment-associated secondary open-angle glaucoma and the closest gonioscopic mimic. Distinguished by age (third to fifth decade, myopic, often male), by mid-peripheral radial spoke-like transillumination from iridozonular chafing rather than peripupillary loss, by a Krukenberg spindle, by dense homogeneous rather than patchy angle pigmentation, and by the absence of capsular deposits and zonular weakness.

Primary open-angle glaucoma

Overlapping Features Distinguished by the anterior segment, not the disc: no capsular or pupillary-border deposits, no peripupillary transillumination, no poor dilation or phacodonesis. Because exfoliation deposits are missed without dilation, some glaucoma labelled primary is exfoliation glaucoma, and the distinction matters because the course and the surgical risks differ.

True capsular exfoliation

Overlapping Features Lamellar delamination of the anterior lens capsule from chronic infrared exposure, classically in glassblowers. A different disease with a different mechanism; the shared name is historical and the reason the prefix pseudo- was introduced.

Show evidence (1 reference)

PMID:38304644 SUPPORT Other

"True exfoliation syndrome is characterized by lamellar delamination of the lens capsule and is caused by exposure to infrared radiation."

Defines the entity this disease must be distinguished from.

Uveitis with pigment or fibrin deposition

Overlapping Features Inflammation can leave pigment and fibrinous debris on the lens and endothelium. Distinguished by cells and flare, keratic precipitates, synechiae, and the absence of the capsular three-zone pattern and of zonular weakness.

🐁

Animal Models

1

Loxl1-null mouse

The only widely used genetic model, and an instructive failure. Mice lacking LOXL1 fail to maintain elastic fibres, with pelvic organ prolapse, emphysematous airspaces, loose skin and vascular abnormalities, and in the eye show a leaky blood-aqueous barrier, subcapsular lens vesiculation and reduced elastin in iris and ciliary body. They do not form exfoliation material and they do not develop raised pressure or glaucoma. The model therefore reports what LOXL1 loss does to elastic tissue, which is the systemic half of the disease, and says nothing about fibrillogenesis, which is the ocular half; it is also a loss-of-function model of a disease whose human genetics are a regulatory dysregulation.

Species

Mouse

Genotype

Loxl1 homozygous null

Publication

PMID:14745449

Pathograph links

Dysregulated LOXL1 Expression and Elastic Microfibril Cross-Linking partially recapitulates fidelity: low observes: tissue Demonstrates that LOXL1 is required for elastic fibre maintenance and that its absence produces systemic elastic tissue failure, which is the biology this node rests on.

Limitations: Complete absence of LOXL1 is not the human lesion, which is a genotype-dependent and stage-dependent dysregulation of expression with excess enzyme early; the model cannot represent the early excess phase at all, and the human coding variants do not abolish the protein.

Show evidence (1 reference)

PMID:14745449 SUPPORT Model Organism

"Here we show that mice lacking the protein lysyl oxidase-like 1 (LOXL1) do not deposit normal elastic fibers in the uterine tract post partum and develop pelvic organ prolapse, enlarged airspaces of the lung, loose skin and vascular abnormalities with concomitant tropoelastin accumulation."

The systemic elastic fibre phenotype of the null mouse.

Exfoliation Material Fibrillogenesis and Deposition fails to recapitulate fidelity: low observes: tissue The defining lesion of the human disease does not occur in the model.

Limitations: Null mice show some anterior-segment features (blood-aqueous barrier leak, lens changes, reduced iris and ciliary elastin) but deposit no macromolecular material, so the model cannot be used to study how exfoliation material forms, what it is made of, or what clears it. The authors conclude that complete disease requires factors beyond LOXL1 loss, which is also what the human genetics say.

Show evidence (1 reference)

PMID:24425853 SUPPORT Model Organism

"Elimination of LOXL1 in mice impairs the blood-aqueous humor barrier in the ocular anterior segment and causes lens abnormalities consistent with cataract formation, but does not result in deposition of macromolecular material or glaucoma."

The explicit negative result: no deposition of material.

Elevated Intraocular Pressure fails to recapitulate fidelity: low observes: organism Pressure stays normal for at least a year, so the model has no glaucoma arm.

Limitations: Without exfoliation material there is nothing to obstruct the meshwork, so the absence of raised pressure follows from the absence of the upstream lesion rather than telling us anything about the outflow biology of the human disease.

Show evidence (1 reference)

PMID:24425853 SUPPORT Model Organism

"Intraocular pressure measurements were within the normal range (16.5 ± 2.0 mm Hg) in null mice up to 1 year of age."

The measured absence of ocular hypertension.

Recorded as an informative negative. There is no faithful animal model of exfoliation syndrome: no species forms the material spontaneously, and LOXL1 loss does not produce it. The HUMAN_MODEL_MISMATCH discussion below carries the consequence for the mechanism chain.

Show evidence (2 references)

PMID:24425853 SUPPORT Model Organism

"These results show that mice lacking LOXL1 have some ES features but that complete disease manifestation requires other factors that could be genetic and/or environmental."

The authors' own assessment of the model's partial fidelity.

PMID:14745449 SUPPORT Model Organism

"Thus elastin polymer deposition is a crucial aspect of elastic fiber maintenance and is dependent on LOXL1, which serves both as a cross-linking enzyme and an element of the scaffold to ensure spatially defined deposition of elastin."

The dual enzyme-and-scaffold role of LOXL1 that the model established, which is the mechanistic content it contributes.

{ }

Source YAML

click to show

name: Exfoliation Syndrome
creation_date: "2026-09-04T23:23:40Z"
description: >-
  Exfoliation syndrome (pseudoexfoliation syndrome, PEX/XFS) is an age-related,
  systemic disorder of the elastic extracellular matrix in which abnormal
  fibrillar material is overproduced, abnormally cross-linked and stably
  deposited in tissues that make elastic fibres. The disease is visible almost
  only in the eye: the pre-equatorial lens epithelium, the nonpigmented ciliary
  epithelium and the iris pigment epithelium secrete microfibrillar aggregates
  containing fibrillin-1, latent TGF-beta binding proteins, clusterin and the
  cross-linking enzyme LOXL1, which settle on the anterior lens capsule in a
  classic three-zone pattern, on the pupillary border, on the zonules and in the
  trabecular meshwork. The mechanism runs from a common LOXL1 susceptibility
  genotype and an aged, TGF-beta1-rich, oxidatively stressed anterior-segment
  milieu, through dysregulated LOXL1 expression and failed extracellular
  chaperoning, to fibrillogenesis; from there the material does mechanical
  damage wherever it lands.

  Three consequences organise the clinical picture. Exfoliation material
  infiltrates and ruptures the zonules, so the lens becomes unstable
  (phacodonesis, subluxation) and cataract surgery carries many times the usual
  risk of zonular dehiscence and capsular rupture. The iris pigment epithelium
  degenerates at the pupillary margin, giving peripupillary transillumination,
  poor mydriasis and a shower of pigment into the anterior chamber. Most
  consequentially, exfoliation material and liberated pigment obstruct the
  trabecular meshwork, outflow resistance rises, intraocular pressure climbs to
  levels that are typically higher and more labile than in primary open-angle
  glaucoma, and the eye develops exfoliation glaucoma, the commonest identifiable
  cause of secondary open-angle glaucoma worldwide and a form with a faster,
  less medically responsive course.

  The distinction that organises this entry is the same one used for pigment
  dispersion: exfoliation syndrome is a risk state, and exfoliation glaucoma is
  what it becomes in a large minority of eyes. The genetics are polygenic
  rather than Mendelian. LOXL1 common variants are present in nearly every
  patient and in most unaffected people, the risk allele reverses direction
  between ancestries, and the syndrome is strongly age-dependent, so LOXL1 is
  curated as a susceptibility locus and not as a causal gene. Systemic
  deposits are real, but the cardiovascular, hearing and pelvic-floor
  associations reported alongside them remain associations, and the entry
  records them as such.
category: Complex
parents:
- Ophthalmological Disease
- Extracellular Matrix Disorder
disease_term:
  preferred_term: Exfoliation Syndrome
  term:
    id: MONDO:0100046
    label: exfoliation syndrome, susceptibility to
mappings:
  mondo_mappings:
  - term:
      id: MONDO:0008327
      label: exfoliation syndrome
    mapping_predicate: skos:exactMatch
    mapping_source: manual curation
    mapping_justification: >-
      MONDO:0008327 is the disease concept proper (synonyms XFS, XFG,
      pseudoexfoliation glaucoma; cross-referenced to DOID:13641, MeSH D017889,
      Orphanet 529819 and NCIT C129025). This entry curates that disease in full,
      so the mapping is an exact match rather than a cross-reference.
synonyms:
- Pseudoexfoliation syndrome
- PEX syndrome
- PXS
- XFS
- Pseudoexfoliation of the lens
- Exfoliation glaucoma (when glaucoma is present)
- Pseudoexfoliation glaucoma
- Capsular glaucoma
references:
- reference: PMID:11166342
  title: "Exfoliation syndrome."
- reference: PMID:16678509
  title: "Ocular and systemic pseudoexfoliation syndrome."
- reference: PMID:28553957
  title: "Genetic association study of exfoliation syndrome identifies a protective rare variant at LOXL1 and five new susceptibility loci."
notes: >-
  Disease term. The entry is keyed on MONDO:0100046 ("exfoliation syndrome,
  susceptibility to") because that is the MONDO identifier the curation stub and
  claim issue were filed under; it is the OMIM 177650 (XFS1) concept and carries
  no synonyms of its own. It is not, however, MONDO's only concept for this
  disease: MONDO:0008327 "exfoliation syndrome" is a live term with the synonyms
  XFS, XFG and pseudoexfoliation glaucoma and the Orphanet, DOID, MeSH and NCIT
  cross-references, and it is the term a reader would expect. It is mapped as an
  exact match under `mappings` so that coverage tooling retires both concepts.
  Repointing `disease_term` to MONDO:0008327 is a reasonable follow-up and is
  flagged in the curation history rather than done silently here.

  The two terms are not duplicates, which is worth stating because they look
  like one. MONDO:0100046 is an `inherited disease susceptibility` class that
  MONDO relates to MONDO:0008327 with `predisposes_towards`; so MONDO carries
  both a disease concept and a susceptibility concept for this entity, and the
  `skos:exactMatch` recorded above is a claim about what this file curates -
  the disease in full - rather than a claim that the two MONDO classes are the
  same thing.

  Gene relation: this entry disagrees with MONDO. MONDO relates both terms to
  LOXL1 with RO:0004003, "has material basis in germline mutation in", and the
  NCIT-derived definition of MONDO:0008327 calls the condition "An autosomal
  dominant disorder caused by mutations in the LOXL1 gene". The genetics
  recorded in the LOXL1 entry below do not support reading it that way: the risk
  allele reverses between ancestries, the coding variants are carried by most
  unaffected people, and the knockout mouse does not form exfoliation material.
  This entry therefore binds LOXL1 as SUSCEPTIBILITY and leaves the disagreement
  visible rather than adopting MONDO's relation. The same reading is implicit in
  MONDO's own structure, which needed a separate "susceptibility to" class to
  express the relationship at all.

  Scope. Exfoliation syndrome and exfoliation glaucoma are curated as one entry,
  as one spectrum, for the reason given in Pigment_Dispersion_Syndrome: the
  chain from deposited material to raised pressure to optic neuropathy is
  continuous, and only the last node changes the diagnosis. The boundary is
  explicit at the node level: everything up to and including elevated
  intraocular pressure is the syndrome, and exfoliation glaucoma requires
  glaucomatous optic neuropathy in addition. True capsular exfoliation (the
  infrared, glassblower's delamination of the lens capsule) is a different
  disease and is listed only as a differential.

  Module conformance. The outflow and optic-neuropathy arm conforms to
  `glaucoma_optic_neuropathy` at four nodes (Trabecular Meshwork Outflow
  Dysfunction, Elevated Intraocular Pressure, Retinal Ganglion Cell Apoptosis,
  Progressive Glaucomatous Optic Neuropathy). The disorder-specific substitution
  is the cause of the trabecular dysfunction: physical obstruction of the
  meshwork by exfoliation material and liberated iris pigment, rather than the
  primary juxtacanalicular pathology of open-angle glaucoma. The entry adds one
  node the module does not have, elastosis of the lamina cribrosa, because it is
  specific to this disease and is the leading explanation for why these optic
  nerves fare worse at a given pressure.

  Genetics. LOXL1 is typed SUSCEPTIBILITY, not CAUSATIVE, and inheritance is
  recorded as polygenic. The reasons are in the genetic block: population
  attributable risk above 99% together with risk-allele carriage in most
  unaffected people, reversal of the rs3825942 risk allele in black South
  Africans and of rs1048661 in Japanese and Koreans, and strong age dependence.
  No GeneReviews chapter exists for this disease (PubMed searched for
  "exfoliation syndrome GeneReviews" and "pseudoexfoliation GeneReviews" on
  2026-09-18; none found), which is expected for a complex trait; there is
  therefore no GeneReviews-tagged reference.

  Systemic associations. Exfoliation material has been demonstrated in visceral
  organs and skin, so the systemic elastosis node is a histological fact. The
  clinical associations that travel with it (cardiovascular and cerebrovascular
  events, sensorineural hearing loss, pelvic organ prolapse) are recorded as
  phenotypes with the association-level evidence that exists, with the caveats
  in their descriptions, and the question of whether they are consequences or
  confounders is a knowledge gap rather than a mechanism.

  Provenance. Built from an Edison Falcon deep-research report
  (research/Exfoliation_Syndrome-deep-research-falcon.md; 17/17 references
  resolved, 2/2 terms resolved, preflight PASS on MONDO:0100046 with LOXL1 as
  the expected gene). Falcon cites by DOI and corpus key, so every DOI used
  was resolved to its PubMed record through the PMC ID converter and all
  evidence here is cited and verified against PMIDs. The report proposed
  MONDO:0008327 as the disease term, which is the discrepancy discussed above.
  Primary mechanism, histopathology, epidemiology and animal-model papers were
  located by PubMed E-utilities searches beyond the report's citation list.
inheritance:
- name: Polygenic inheritance
  inheritance_term:
    preferred_term: Polygenic inheritance
    term:
      id: HP:0010982
      label: Polygenic inheritance
  penetrance: INCOMPLETE
  expressivity: VARIABLE
  description: >-
    Familial aggregation is well documented and the LOXL1 locus carries an
    extraordinary population attributable risk, yet the same variants are
    carried by most unaffected people and the disease is strongly age-dependent,
    so inheritance is polygenic with incomplete, age-related penetrance rather
    than Mendelian. Additional genome-wide loci (CACNA1A, POMP, TMEM136, AGPAT1,
    RBMS3, SEMA6A) and rare CYP39A1 variants each add modest risk.
  evidence:
  - reference: PMID:23157966
    reference_title: "Pseudoexfoliation syndrome, a systemic disorder with ocular manifestations."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "PXS familial aggregation suggests genetic inheritance."
    explanation: >-
      Establishes the familial clustering that motivates a genetic model, while
      stopping short of a Mendelian claim.
  - reference: PMID:23157966
    reference_title: "Pseudoexfoliation syndrome, a systemic disorder with ocular manifestations."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "Two of these SNPs confer a higher than 99% population attributable risk for PXS and PXG in the Nordic population; however, they carry different risks in different populations."
    explanation: >-
      A near-total population attributable risk from common alleles that carry
      different risks in different populations is the signature of a complex
      susceptibility locus, not of a causal Mendelian gene.
  - reference: PMID:25188364
    reference_title: "Solar exposure and residential geographic history in relation to exfoliation syndrome in the United States and Israel."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "However, 80% of controls also harbor these variants and the ratio of cases to controls with trait-related variants is fairly similar in regions where XFS is hyper-endemic"
    explanation: >-
      Risk-allele carriage in four fifths of unaffected controls is the
      incomplete penetrance that makes the polygenic, gene-environment model
      necessary.
pathophysiology:
- name: LOXL1 Susceptibility Genotype
  biological_scale: MOLECULAR
  description: >-
    The genetic root of the entry, and deliberately a susceptibility rather than
    a lesion. Two common coding variants in exon 1 of LOXL1 (rs1048661
    p.Arg141Leu, rs3825942 p.Gly153Asp) and the intronic rs2165241 were found by
    the original Icelandic and Swedish genome-wide search to explain essentially
    all of the association at 15q24.1, with the highest-risk haplotype
    homozygous in a quarter of the population. The coding variants are not the
    functional ones: the risk allele at rs3825942 is reversed in black South
    Africans and at rs1048661 in Japanese and Koreans, which no simple
    protein-altering model survives, and the functional signal has since been
    located in noncoding regulatory sequence spanning introns 1 and 2, where
    rs11638944 alters RXR-alpha binding and LOXL1 splicing and where risk
    alleles modulate the promoter of the antisense lncRNA LOXL1-AS1. A rare
    coding allele, p.Phe407, is strongly protective. What the genotype changes
    is therefore how much LOXL1 a cell makes and how it responds to stress, not
    whether the enzyme works.
  genes:
  - preferred_term: LOXL1
    term:
      id: hgnc:6665
      label: LOXL1
  molecular_functions:
  - preferred_term: LOXL1 lysyl oxidase activity
    term:
      id: GO:0004720
      label: protein-lysine 6-oxidase activity
  evidence:
  - reference: PMID:17690259
    reference_title: "Common sequence variants in the LOXL1 gene confer susceptibility to exfoliation glaucoma."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Two nonsynonymous SNPs in exon 1 of the gene LOXL1 explain the association, and the data suggest that they confer risk of XFG mainly through exfoliation syndrome (XFS)."
    explanation: >-
      The founding genetic result: the LOXL1 association is with the syndrome,
      and glaucoma risk is carried through it. This is why the genotype sits at
      the head of the syndrome chain rather than at the glaucoma end.
  - reference: PMID:17690259
    reference_title: "Common sequence variants in the LOXL1 gene confer susceptibility to exfoliation glaucoma."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "About 25% of the general population is homozygous for the highest-risk haplotype, and their risk of suffering from XFG is more than 100 times that of individuals carrying only low-risk haplotypes."
    explanation: >-
      A risk haplotype carried homozygously by a quarter of the population is a
      susceptibility allele by definition; the 100-fold relative risk is real
      but is relative to a rare low-risk group.
  - reference: PMID:28534485
    reference_title: "Pseudoexfoliation syndrome-associated genetic variants affect transcription factor binding and alternative splicing of LOXL1."
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: "We find that the rs11638944:C>G transversion exerts a cis-acting effect on the expression levels of LOXL1, mediated by differential binding of the transcription factor RXRα (retinoid X receptor alpha) and by modulating alternative splicing of LOXL1, eventually leading to reduced levels of LOXL1 mRNA in cells and tissues of risk allele carriers."
    explanation: >-
      The functional variant is regulatory and acts on LOXL1 expression and
      splicing, which is why this node is described as a change in how much
      LOXL1 a cell makes rather than a change in the enzyme.
  - reference: PMID:28553957
    reference_title: "Genetic association study of exfoliation syndrome identifies a protective rare variant at LOXL1 and five new susceptibility loci."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "We identified a rare protective allele at LOXL1 (p.Phe407, odds ratio (OR) = 25, P = 2.9 × 10-14) through deep resequencing of XFS cases and controls from nine countries."
    explanation: >-
      Records the protective rare coding allele that, unlike the common
      variants, behaves consistently across populations.
  downstream:
  - target: TGF-beta1 Excess and Oxidative Stress in the Anterior Segment
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    description: >-
      The genotype couples to the cellular stress response through LOXL1-AS1:
      risk alleles alter the activity of the lncRNA promoter, and the lncRNA
      itself responds to oxidative and mechanical stress. This is the
      gene-environment junction of the disease, and it is an interaction claim
      rather than a claim that the genotype produces the stress.
    evidence:
    - reference: PMID:26307087
      reference_title: "Genetic variants and cellular stressors associated with exfoliation syndrome modulate promoter activity of a lncRNA within the LOXL1 locus."
      supports: SUPPORT
      evidence_source: IN_VITRO
      snippet: "We show that this region contains a promoter and, importantly, that the strongly associated XFS risk alleles in the South African population are functional variants that significantly modulate the activity of this promoter."
      explanation: >-
        The risk alleles are functional at a stress-responsive promoter, which
        is what makes the edge from genotype to stress response a mechanism
        rather than a coincidence.
    - reference: PMID:26307087
      reference_title: "Genetic variants and cellular stressors associated with exfoliation syndrome modulate promoter activity of a lncRNA within the LOXL1 locus."
      supports: SUPPORT
      evidence_source: IN_VITRO
      snippet: "LOXL1-AS1 expression is also significantly altered in response to oxidative stress in human lens epithelial cells and in response to cyclic mechanical stress in human Schlemm's canal endothelial cells."
      explanation: >-
        The same locus answers to oxidative and mechanical stress in the two
        cell types that matter most here, which is the interaction this edge
        encodes.
  - target: Dysregulated LOXL1 Expression and Elastic Microfibril Cross-Linking
    causal_link_type: DIRECT
    description: >-
      Genotype sets the baseline level of LOXL1 in ocular tissue: expression
      falls by about a fifth per rs1048661 risk allele, and the intronic
      regulatory risk allele lowers LOXL1 mRNA in carriers.
    evidence:
    - reference: PMID:18974306
      reference_title: "Genotype-correlated expression of lysyl oxidase-like 1 in ocular tissues of patients with pseudoexfoliation syndrome/glaucoma and normal patients."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "LOXL1 ocular expression was reduced by approximately 20% per risk allele of rs1048661, whereas risk alleles of rs3825942, which were highly overrepresented in PEX cases, did not affect LOXL1 expression levels."
      explanation: >-
        A genotype-dependent expression effect measured in human ocular tissue,
        and an honest one: it is confined to one of the two coding SNPs, so the
        edge is real but does not explain the whole association.
- name: TGF-beta1 Excess and Oxidative Stress in the Anterior Segment
  biological_scale: TISSUE
  description: >-
    The milieu in which the matrix disorder unfolds, and the node where age and
    environment enter. The aqueous humour of affected eyes carries significantly
    more total and active TGF-beta1 than control eyes, while TGF-beta2 is
    unchanged; TGF-beta1, LTBP-1 and LTBP-2 are overexpressed in anterior-segment
    tissue, most strongly in the nonpigmented ciliary epithelium; antioxidant
    defence in the aqueous is reduced; and interleukin-6 and -8 run about
    threefold above controls. Ultraviolet light, hypoxia and homocysteine have
    each been proposed as drivers of this state, and the epidemiology of
    lifetime sunlight exposure supports at least the first. Latitude and
    reflected light are recorded as an environmental entry that acts on this
    node.
  biological_processes:
  - preferred_term: TGF-beta1 signaling in the anterior segment
    modifier: INCREASED
    term:
      id: GO:0007179
      label: transforming growth factor beta receptor signaling pathway
  - preferred_term: oxidative stress in the aqueous humour and anterior segment
    modifier: INCREASED
    term:
      id: GO:0006979
      label: response to oxidative stress
  locations:
  - preferred_term: anterior segment of the eye
    term:
      id: UBERON:0001801
      label: anterior segment of eyeball
  cell_types:
  - preferred_term: nonpigmented ciliary epithelial cell
    term:
      id: CL:0002304
      label: non-pigmented ciliary epithelial cell
  evidence:
  - reference: PMID:11846508
    reference_title: "Role of transforming growth factor-beta1 and its latent form binding protein in pseudoexfoliation syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Significantly increased concentrations of both total and active TGF-beta1 were measured in the aqueous humor of PEX eyes without and with glaucoma as compared to control eyes, whereas levels of TGF-beta2 were not significantly different."
    explanation: >-
      The direct measurement behind the node, with the isoform specificity that
      makes TGF-beta1 rather than TGF-beta the claim.
  - reference: PMID:11846508
    reference_title: "Role of transforming growth factor-beta1 and its latent form binding protein in pseudoexfoliation syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The expression of TGF-beta1, LTBP-1, and LTBP-2, but not TGF-beta2, was markedly increased in anterior segment tissues of PEX eyes, particularly in the non-pigmented epithelium of the ciliary body, on both the mRNA and the protein level."
    explanation: >-
      Localises the excess to the nonpigmented ciliary epithelium, which is
      also the cell type that produces exfoliation material and is bound on
      this node for that reason.
  - reference: PMID:29401156
    reference_title: "Growth Factors, Oxidative Damage, and Inflammation in Exfoliation Syndrome."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "Furthermore, results from several studies find that the aqueous humor of exfoliation glaucoma patients exhibits a decreased antioxidant defense and increased oxidative stress systems."
    explanation: >-
      The oxidative half of the node, from a review pooling the aqueous humour
      studies.
  - reference: PMID:29401156
    reference_title: "Growth Factors, Oxidative Damage, and Inflammation in Exfoliation Syndrome."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "Finally, studies show that the levels of interleukin-6 and interleukin-8 in the aqueous humor of XFS patients were 3-fold higher than in controls."
    explanation: >-
      Adds the low-grade inflammatory component; the review is cited because it
      is where the pooled figure lives.
  - reference: PMID:16678509
    reference_title: "Ocular and systemic pseudoexfoliation syndrome."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "The current pathogenetic concept describes PEX syndrome as an elastic microfibrillopathy involving transforming growth factor-beta1, oxidative stress, and impaired cellular protection mechanisms as key pathogenetic factors."
    explanation: >-
      The consensus statement of the mechanism, naming the three factors that
      this node and the next two encode.
  downstream:
  - target: Dysregulated LOXL1 Expression and Elastic Microfibril Cross-Linking
    causal_link_type: DIRECT
    description: >-
      TGF-beta1, oxidative stress, ultraviolet light and hypoxia each induce
      LOXL1 and the elastic proteins of exfoliation material in cultured
      fibroblasts, and TGF-beta1 with oxidative stress drives their assembly
      into PEX-like fibrils. This is the edge that turns a milieu into a matrix
      lesion.
    evidence:
    - reference: PMID:21948647
      reference_title: "Regulation of lysyl oxidase-like 1 (LOXL1) and elastin-related genes by pathogenic factors associated with pseudoexfoliation syndrome."
      supports: SUPPORT
      evidence_source: IN_VITRO
      snippet: "Treatment of fibroblasts with TGF-β1, oxidative stress, UV light, and hypoxia induced a significant increase in expression levels of LOXL1 and elastic proteins, whereas the effect of IL-6 was limited to induction of elastic constituents."
      explanation: >-
        The inducing stimuli are exactly the components of the upstream node,
        and the induced genes are exactly the components of the downstream one.
    - reference: PMID:11846508
      reference_title: "Role of transforming growth factor-beta1 and its latent form binding protein in pseudoexfoliation syndrome."
      supports: SUPPORT
      evidence_source: IN_VITRO
      snippet: "The expression of mRNA coding for fibrillin-1 was up-regulated in vitro by TGF-beta1."
      explanation: >-
        Fibrillin-1 is the principal microfibrillar component of the material,
        and this is the direct demonstration that TGF-beta1 induces it.
  - target: Extracellular Chaperone Deficiency and Impaired Proteostasis
    causal_link_type: DIRECT
    description: >-
      TGF-beta1 represses clusterin in nonpigmented ciliary epithelial cells, so
      the same signal that drives matrix synthesis removes the chaperone that
      would keep the product soluble.
    evidence:
    - reference: PMID:16639006
      reference_title: "Clusterin deficiency in eyes with pseudoexfoliation syndrome may be implicated in the aggregation and deposition of pseudoexfoliative material."
      supports: SUPPORT
      evidence_source: IN_VITRO
      snippet: "The expression of clusterin mRNA and protein in nonpigmented ciliary epithelial cells was significantly downregulated by TGF-beta1 in vitro."
      explanation: >-
        The direct demonstration of the edge in the relevant cell type.
- name: Dysregulated LOXL1 Expression and Elastic Microfibril Cross-Linking
  biological_scale: MOLECULAR
  description: >-
    LOXL1 is the cross-linking enzyme specifically required for elastic fibre
    formation and stabilisation, and in this disease it is regulated in the
    wrong direction at the wrong time. Ocular LOXL1 expression is significantly
    increased in early disease and decreased in advanced disease regardless of
    genotype, LOXL1 protein is a major component of the fibrillar aggregates in
    both intraocular and extraocular sites, and it co-localises with elastic
    fibre components on the fibrils. The working model is that excess LOXL1
    during the initial fibrogenic phase participates in cross-linking elastic
    microfibrillar components (fibrillin-1, fibulins, tropoelastin) into
    abnormal aggregates, and that inadequate LOXL1 later promotes elastotic
    degeneration of existing elastic tissue. The N-terminal domain of LOXL1 is
    intrinsically disordered and misfolding-prone, with the risk residue 153 at
    the point of maximal disorder, which is the basis of the proteopathy
    reading of the disease.
  genes:
  - preferred_term: LOXL1
    term:
      id: hgnc:6665
      label: LOXL1
  molecular_functions:
  - preferred_term: LOXL1 lysyl oxidase activity
    modifier: DYSREGULATED
    term:
      id: GO:0004720
      label: protein-lysine 6-oxidase activity
  biological_processes:
  - preferred_term: elastic microfibril assembly and cross-linking
    modifier: DYSREGULATED
    term:
      id: GO:0048251
      label: elastic fiber assembly
  evidence:
  - reference: PMID:18974306
    reference_title: "Genotype-correlated expression of lysyl oxidase-like 1 in ocular tissues of patients with pseudoexfoliation syndrome/glaucoma and normal patients."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Irrespective of the individual genotype, LOXL1 expression was significantly increased in early PEX stages but was decreased in advanced stages both with and without glaucoma compared with controls, whereas LOX and LOXL2 showed no differences between groups."
    explanation: >-
      The stage-dependent, isoform-specific expression change that makes this a
      dysregulation node rather than a simple loss or gain.
  - reference: PMID:18974306
    reference_title: "Genotype-correlated expression of lysyl oxidase-like 1 in ocular tissues of patients with pseudoexfoliation syndrome/glaucoma and normal patients."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "LOXL1 was also found to be a major component of fibrillar PEX aggregates in both intra- and extraocular locations and to co-localize with various elastic fiber components."
    explanation: >-
      Places the enzyme physically in the lesion alongside its substrates, which
      is what a cross-linking pathogenesis predicts.
  - reference: PMID:18809397
    reference_title: "Molecular pathology of pseudoexfoliation syndrome/glaucoma--new insights from LOXL1 gene associations."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "While increased levels of LOXL1 participate in the formation of abnormal PEX fiber aggregates in the initial phase of fibrogenesis, inadequate tissue levels may promote elastotic processes in advanced stages of the disease."
    explanation: >-
      The two-phase model in the words of the group that proposed it: excess
      early, deficiency late.
  - reference: PMID:17690259
    reference_title: "Common sequence variants in the LOXL1 gene confer susceptibility to exfoliation glaucoma."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The product of LOXL1 catalyzes the formation of elastin fibers found to be a major component of the lesions in XFG."
    explanation: >-
      Connects the enzyme's known biochemistry to the composition of the
      deposits.
  downstream:
  - target: Exfoliation Material Fibrillogenesis and Deposition
    causal_link_type: DIRECT
    description: >-
      Altered LOXL1 activation, processing or substrate specificity aggregates
      elastic fibre components into the characteristic fibrils; in culture,
      TGF-beta1 and oxidative stress produce LOXL1-containing microfibrillar
      networks that focally aggregate into PEX-like fibrils.
    evidence:
    - reference: PMID:18974306
      reference_title: "Genotype-correlated expression of lysyl oxidase-like 1 in ocular tissues of patients with pseudoexfoliation syndrome/glaucoma and normal patients."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "Alterations of LOXL1 activation, processing, and/or substrate specificity may contribute to the abnormal aggregation of elastic fiber components into characteristic PEX fibrils."
      explanation: >-
        The authors' own statement of the causal step, hedged as it should be.
    - reference: PMID:21948647
      reference_title: "Regulation of lysyl oxidase-like 1 (LOXL1) and elastin-related genes by pathogenic factors associated with pseudoexfoliation syndrome."
      supports: SUPPORT
      evidence_source: IN_VITRO
      snippet: "Immunohistochemistry and electron microscopy confirmed an upregulation of LOXL1 and elastic fiber proteins and their assembly into extracellular microfibrillar networks with focal aggregation of microfibrils into PEX-like fibrils on stimulation with TGF-β1 and oxidative stress."
      explanation: >-
        The step reproduced in a dish: induced LOXL1 and elastic proteins
        assemble into networks and aggregate into PEX-like fibrils.
  - target: Systemic Elastosis
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    description: >-
      The same elastic-matrix process runs in extraocular tissue: LOXL1 is a
      component of extraocular as well as intraocular aggregates, and deposits
      in visceral organs sit next to elastic and oxytalan fibres. What
      determines which organs deposit material, and why the eye is so much more
      affected, is not known.
    evidence:
    - reference: PMID:1463419
      reference_title: "Pseudoexfoliative fibrillopathy in visceral organs of a patient with pseudoexfoliation syndrome."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "These findings suggest that pseudoexfoliation is a systemic process involving abnormal matrix synthesis, particularly as related to elastic tissue components."
      explanation: >-
        Frames the systemic deposits as the same elastic-matrix process rather
        than a separate one.
  - target: Lamina Cribrosa Elastosis
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    description: >-
      Marked, site-specific elastosis of the lamina cribrosa in exfoliation
      glaucoma, without typical exfoliation fibres, suggests abnormal regulation
      of elastin synthesis or degradation in the optic nerve. It is placed
      downstream of the elastic-fibre dysregulation node on that reading; the
      intermediates are not established.
    evidence:
    - reference: PMID:7777294
      reference_title: "Elastosis of the lamina cribrosa in pseudoexfoliation syndrome with glaucoma."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "The authors' findings demonstrate marked and site-specific elastosis in the lamina cribrosa of patients with pseudoexfoliation syndrome with glaucoma, suggesting an abnormal regulation of elastin synthesis and/or degradation in the optic nerve of patients with this disease."
      explanation: >-
        The abnormal elastin regulation the authors infer is the process this
        edge carries into the optic nerve head.
- name: Extracellular Chaperone Deficiency and Impaired Proteostasis
  biological_scale: CELLULAR
  description: >-
    The failure of the cell's protective machinery, the third leg of the
    consensus model. Clusterin, a highly efficient extracellular chaperone, is
    transcriptionally downregulated in every anterior-segment tissue of affected
    eyes and reduced in their aqueous humour, yet binds prominently to every
    deposit, which is what a chaperone overwhelmed by its substrate looks like.
    Inside the cell, patient-derived Tenon fibroblasts show defective lysosomal
    positioning, microtubule organisation, autophagic flux and mitochondrial
    health, and a substantial fraction of their LOXL1 is routed to autophagic
    degradation, which is why the disease has been proposed as an aggregopathy
    in the same family as the neurodegenerative proteinopathies.
  cell_types:
  - preferred_term: nonpigmented ciliary epithelial cell
    term:
      id: CL:0002304
      label: non-pigmented ciliary epithelial cell
  - preferred_term: Tenon's capsule fibroblast
    term:
      id: CL:0000057
      label: fibroblast
  biological_processes:
  - preferred_term: autophagic clearance
    modifier: DECREASED
    term:
      id: GO:0006914
      label: autophagy
  evidence:
  - reference: PMID:16639006
    reference_title: "Clusterin deficiency in eyes with pseudoexfoliation syndrome may be implicated in the aggregation and deposition of pseudoexfoliative material."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Real-time PCR and in situ hybridization displayed significant downregulation of clusterin mRNA in all anterior segment tissues of PEX eyes, irrespective of the presence or type of glaucoma, compared with normal and glaucomatous control eyes, whereas posterior segment tissues did not show any differential expression."
    explanation: >-
      The chaperone deficiency, measured in human tissue and confined to the
      anterior segment where the material forms.
  - reference: PMID:16639006
    reference_title: "Clusterin deficiency in eyes with pseudoexfoliation syndrome may be implicated in the aggregation and deposition of pseudoexfoliative material."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Considering the known role of clusterin as a highly efficient extracellular chaperone, its deficiency in the anterior segment of PEX eyes may promote the stress-induced aggregation and stable deposition of the pathologic extracellular matrix product characteristic of PEX syndrome."
    explanation: >-
      The interpretation that links chaperone loss to aggregation, in the
      authors' hedged form.
  - reference: PMID:29547474
    reference_title: "Exfoliation Syndrome: A Disease of Autophagy and LOXL1 Proteopathy."
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: "We have documented defects in lysosomal positioning, microtubule organization, autophagy processing rate, and mitochondrial health."
    explanation: >-
      The intracellular proteostasis defects, documented in patient-derived
      fibroblasts. IN_VITRO because the cells are cultured; the caveat that
      they come from trabeculectomy specimens of advanced disease is recorded
      in the knowledge-gap discussion.
  downstream:
  - target: Exfoliation Material Fibrillogenesis and Deposition
    causal_link_type: DIRECT
    description: >-
      Without adequate chaperoning and clearance, stress-induced matrix
      product aggregates and is stably deposited rather than kept soluble and
      removed.
    evidence:
    - reference: PMID:16639006
      reference_title: "Clusterin deficiency in eyes with pseudoexfoliation syndrome may be implicated in the aggregation and deposition of pseudoexfoliative material."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "Considering the known role of clusterin as a highly efficient extracellular chaperone, its deficiency in the anterior segment of PEX eyes may promote the stress-induced aggregation and stable deposition of the pathologic extracellular matrix product characteristic of PEX syndrome."
      explanation: >-
        States the edge directly: chaperone deficiency promotes aggregation and
        stable deposition.
- name: Exfoliation Material Fibrillogenesis and Deposition
  biological_scale: TISSUE
  description: >-
    The lesion that gives the disease its name. Abnormal fibrillar
    extracellular material, made of microfibrils coated with amorphous
    material and containing fibrillin-1, LTBP-1 and -2, latent TGF-beta1,
    LOXL1, clusterin, fibulins and basement-membrane components, is produced by
    the pre-equatorial lens epithelium, the nonpigmented ciliary epithelium,
    the iris pigment epithelium, the corneal and trabecular endothelium and
    most iris stromal cell types, and accumulates on the anterior lens capsule
    in the classic pattern of a central disc, a clear intermediate zone and a
    granular peripheral ring, on the pupillary border, on the zonules and in
    the trabecular meshwork. It is insoluble and it is not cleared. Everything
    downstream is what this material does mechanically to the structures it
    lands on.
  cell_types:
  - preferred_term: pre-equatorial lens epithelial cell
    term:
      id: CL:0002224
      label: lens epithelial cell
  - preferred_term: nonpigmented ciliary epithelial cell
    term:
      id: CL:0002304
      label: non-pigmented ciliary epithelial cell
  - preferred_term: iris pigment epithelial cell
    term:
      id: CL:0002565
      label: iris pigment epithelial cell
  biological_processes:
  - preferred_term: abnormal extracellular matrix deposition
    modifier: DYSREGULATED
    term:
      id: GO:0030198
      label: extracellular matrix organization
  locations:
  - preferred_term: anterior lens capsule
    term:
      id: UBERON:0001804
      label: capsule of lens
  - preferred_term: anterior segment of the eye
    term:
      id: UBERON:0001801
      label: anterior segment of eyeball
  evidence:
  - reference: PMID:11166342
    reference_title: "Exfoliation syndrome."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "Exfoliation syndrome (XFS) is an age-related disease in which abnormal fibrillar extracellular material is produced and accumulates in many ocular tissues."
    explanation: >-
      The definition of the disease is the definition of this node.
  - reference: PMID:11166342
    reference_title: "Exfoliation syndrome."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "Regardless of etiology, typical exfoliation fibers have been demonstrated electron microscopically in close association with the pre-equatorial lens epithelium, the nonpigmented ciliary epithelium, the iris pigment epithelium, the corneal endothelium, the trabecular endothelium, and with almost all cell types of the iris stroma, such as fibrocytes, melanocytes, vascular endothelial cells, pericytes, and smooth muscle cells."
    explanation: >-
      Names the producing cell types, which is why three of them are bound on
      this node.
  - reference: PMID:11846508
    reference_title: "Role of transforming growth factor-beta1 and its latent form binding protein in pseudoexfoliation syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Double immunolabeling revealed clear co-localization of LTBP-1 and -2 with latent TGF-beta1 and with fibrillin-1 on PEX fibrils."
    explanation: >-
      The molecular composition of the fibrils, tying them to the TGF-beta1
      and fibrillin biology upstream.
  - reference: PMID:16678509
    reference_title: "Ocular and systemic pseudoexfoliation syndrome."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "PEX syndrome is a common age-related generalized fibrotic matrix process of worldwide significance, which may not only cause severe chronic open-angle glaucoma and cataract, but also a spectrum of other serious spontaneous and surgical intraocular complications."
    explanation: >-
      Places the deposition as the cause of the whole downstream spectrum:
      glaucoma, cataract, and the spontaneous and surgical complications.
  downstream:
  - target: Zonular Degradation and Lens Instability
    causal_link_type: DIRECT
    description: >-
      Material produced by the nonpigmented ciliary epithelium and the lens
      epithelium intercalates at the zonular anchorage, infiltrates the bundles
      in the pars plicata and erupts through the capsular surface at the
      insertion, rupturing the zonules at all three levels.
    evidence:
    - reference: PMID:7977599
      reference_title: "A histopathologic study of zonular instability in pseudoexfoliation syndrome."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "The production of pseudoexfoliation material by both the nonpigmented ciliary epithelium and the pre-equatorial lens epithelium resulted in typical alterations of the zonules at three levels."
      explanation: >-
        The histopathological demonstration that the material itself is what
        damages the zonules.
  - target: Iris Pigment Epithelial Degeneration and Pigment Dispersion
    causal_link_type: DIRECT
    description: >-
      Deposition in and around the iris pigment epithelium at the pupillary
      margin degrades that layer and releases pigment into the anterior
      chamber.
    evidence:
    - reference: PMID:11166342
      reference_title: "Exfoliation syndrome."
      supports: SUPPORT
      evidence_source: OTHER
      snippet: "Pigment loss from the iris sphincter region and its deposition on anterior chamber structures is a hallmark of XFS."
      explanation: >-
        Establishes pigment loss from the sphincter region as a defining
        consequence of the syndrome.
  - target: Trabecular Meshwork Obstruction by Exfoliation Material and Pigment
    causal_link_type: DIRECT
    description: >-
      Material carried by aqueous flow, together with liberated pigment,
      deposits in the trabecular meshwork and obstructs the outflow pathway.
    evidence:
    - reference: PMID:29401156
      reference_title: "Growth Factors, Oxidative Damage, and Inflammation in Exfoliation Syndrome."
      supports: SUPPORT
      evidence_source: OTHER
      snippet: "The primary consequence of the presence of this material in the eye is an elevation of intraocular pressure (IOP), most likely due to the release of XFM and iris pigment particles and their deposition in the trabecular meshwork (TM), leading to physical obstruction of the aqueous humor outflow pathway in the TM."
      explanation: >-
        States the causal step from deposited material and pigment to physical
        obstruction of the meshwork.
  - target: Pseudoexfoliation
    causal_link_type: DIRECT
    description: >-
      The deposits on the anterior lens capsule and pupillary border are the
      diagnostic sign itself.
- name: Zonular Degradation and Lens Instability
  biological_scale: TISSUE
  description: >-
    The first of the three mechanical consequences. Exfoliation material
    separates the zonular bundles from the disrupted basement membrane of the
    nonpigmented epithelium at their origin, infiltrates them alongside the
    ciliary processes to the point of rupture, and lifts and ruptures the
    zonular lamella at the lens capsule; lysosomal enzymes within the
    aggregates indicate that proteolysis assists the disintegration. The lens
    then moves: phacodonesis, subluxation and frank dislocation follow, and the
    same weakness is why zonular dehiscence, capsular rupture and vitreous loss
    complicate cataract surgery many times more often than in other eyes.
    Zonular laxity also lets the lens-iris diaphragm move forward, which is the
    accepted basis for the angle-closure predisposition of this disease.
  locations:
  - preferred_term: zonular fibres
    term:
      id: UBERON:0006762
      label: suspensory ligament of lens
  evidence:
  - reference: PMID:7977599
    reference_title: "A histopathologic study of zonular instability in pseudoexfoliation syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "In the pars plicata of the ciliary body, pseudoexfoliation material infiltrated the zonular bundles passing alongside the ciliary processes leading to zonular rupture."
    explanation: >-
      The direct ultrastructural observation of material infiltrating and
      rupturing the zonules.
  - reference: PMID:7977599
    reference_title: "A histopathologic study of zonular instability in pseudoexfoliation syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The immunohistochemical demonstration of lysosomal enzymes within pseudoexfoliation aggregates indicates that proteolytic mechanisms facilitate zonular disintegration."
    explanation: >-
      Adds the proteolytic component of the disintegration.
  - reference: PMID:11166342
    reference_title: "Exfoliation syndrome."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "The presence of XFS should alert the physician to the increased risks of intraocular surgery, most commonly zonular dehiscence, capsular rupture, and vitreous loss during cataract extraction."
    explanation: >-
      The surgical consequence of the zonular weakness, which is the reason
      this node is clinically important out of proportion to its size.
  downstream:
  - target: Phakodonesis
    causal_link_type: DIRECT
    description: >-
      A loose zonular apparatus lets the lens tremble with eye movement.
  - target: Lens subluxation
    causal_link_type: DIRECT
    description: >-
      Progressive zonular loss displaces the lens, spontaneously or late after
      cataract surgery as the capsular bag and implant dislocate together.
  - target: Angle closure glaucoma
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    description: >-
      Exfoliation eyes are predisposed to angle closure; forward movement of a
      lens on lax zonules is the accepted explanation, though the cited review
      records the predisposition without demonstrating the intermediate step.
    evidence:
    - reference: PMID:11166342
      reference_title: "Exfoliation syndrome."
      supports: SUPPORT
      evidence_source: OTHER
      directness: INDIRECT
      snippet: "Patients with XFS are also predisposed to develop angle-closure glaucoma, and glaucoma in XFS has a more serious clinical course and worse prognosis than primary open-angle glaucoma."
      explanation: >-
        Establishes the predisposition; INDIRECT because the sentence does not
        itself attribute it to zonular laxity.
- name: Iris Pigment Epithelial Degeneration and Pigment Dispersion
  biological_scale: CELLULAR
  description: >-
    The second mechanical consequence, and the point of contact with pigment
    dispersion syndrome. Deposition at the pupillary margin degrades the iris
    pigment epithelium of the sphincter region, producing peripupillary
    transillumination defects and releasing pigment that settles on the
    anterior chamber structures and, on gonioscopy, as patchy trabecular
    hyperpigmentation with a wavy pigment line anterior to Schwalbe's line
    (Sampaolesi line). Iris stromal and sphincter involvement is why the pupil
    dilates poorly, a small point with large surgical consequences. Unlike
    pigment dispersion syndrome the liberation is degenerative rather than
    mechanical, and the transillumination is peripupillary rather than
    mid-peripheral.
  cell_types:
  - preferred_term: iris pigment epithelial cell
    term:
      id: CL:0002565
      label: iris pigment epithelial cell
  locations:
  - preferred_term: iris
    term:
      id: UBERON:0001769
      label: iris
  evidence:
  - reference: PMID:11166342
    reference_title: "Exfoliation syndrome."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "Pigment loss from the iris sphincter region and its deposition on anterior chamber structures is a hallmark of XFS."
    explanation: >-
      Both halves of the node in one sentence: the loss at the sphincter and
      the deposition elsewhere.
  - reference: PMID:38304644
    reference_title: "Cardiovascular Manifestations of Pseudoexfoliation Syndrome: A Narrative Review."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "Symptoms of PEX include elevated intraocular pressure, peripapillary transillumination deficiencies, potential glaucomatous optic nerve damage, poor dilatation, Sampaolesi line, and fibrillar white flaky deposits along the pupillary border."
    explanation: >-
      Lists the transillumination defects, poor dilatation and Sampaolesi line
      that this node produces. Quoted verbatim, including the source's
      "peripapillary" where peripupillary is meant.
  downstream:
  - target: Iris transillumination defect
    causal_link_type: DIRECT
    description: >-
      Loss of the pigmented layer at the pupillary margin lets light through.
  - target: Poor pupillary dilation
    causal_link_type: DIRECT
    description: >-
      Degeneration of the iris sphincter region and stroma limits
      pharmacological mydriasis.
  - target: Trabecular Meshwork Obstruction by Exfoliation Material and Pigment
    causal_link_type: DIRECT
    description: >-
      Liberated pigment is carried by the aqueous into the meshwork, adding a
      second particulate load to the exfoliation material already there.
    evidence:
    - reference: PMID:29401156
      reference_title: "Growth Factors, Oxidative Damage, and Inflammation in Exfoliation Syndrome."
      supports: SUPPORT
      evidence_source: OTHER
      snippet: "The primary consequence of the presence of this material in the eye is an elevation of intraocular pressure (IOP), most likely due to the release of XFM and iris pigment particles and their deposition in the trabecular meshwork (TM), leading to physical obstruction of the aqueous humor outflow pathway in the TM."
      explanation: >-
        Names iris pigment particles alongside the material as what obstructs
        the meshwork.
  - target: Pigment deposition in the trabecular meshwork
    causal_link_type: DIRECT
    description: >-
      The gonioscopic sign of the dispersed pigment, kept separate from the
      outflow node because pigmentation of the angle is present in eyes with
      normal pressure.
- name: Trabecular Meshwork Obstruction by Exfoliation Material and Pigment
  biological_scale: TISSUE
  description: >-
    The third mechanical consequence and the one that matters most. Exfoliation
    material and iris pigment carried by aqueous flow deposit in the trabecular
    meshwork and juxtacanalicular tissue, physically obstruct the outflow
    pathway and raise resistance; in older eyes the age-related narrowing of the
    outflow channels to the inner wall of Schlemm's canal makes the load harder
    to clear. This is the disorder-specific substitution into the glaucoma
    module: the trabecular dysfunction here is obstruction by deposited
    material rather than the intrinsic juxtacanalicular pathology of primary
    open-angle glaucoma, and unlike pigment dispersion syndrome the material
    is not phagocytosable debris but insoluble cross-linked fibrils.
  conforms_to: "glaucoma_optic_neuropathy#Trabecular Meshwork Outflow Dysfunction"
  cell_types:
  - preferred_term: trabecular meshwork cell
    term:
      id: CL:0002367
      label: trabecular meshwork cell
  locations:
  - preferred_term: trabecular meshwork
    term:
      id: UBERON:0005969
      label: eye trabecular meshwork
  biological_processes:
  - preferred_term: trabecular extracellular matrix obstruction
    modifier: DYSREGULATED
    term:
      id: GO:0030198
      label: extracellular matrix organization
  evidence:
  - reference: PMID:29401156
    reference_title: "Growth Factors, Oxidative Damage, and Inflammation in Exfoliation Syndrome."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "The primary consequence of the presence of this material in the eye is an elevation of intraocular pressure (IOP), most likely due to the release of XFM and iris pigment particles and their deposition in the trabecular meshwork (TM), leading to physical obstruction of the aqueous humor outflow pathway in the TM."
    explanation: >-
      The mechanism of the node in full: material plus pigment, deposited in
      the meshwork, physically obstructing outflow.
  - reference: PMID:28534485
    reference_title: "Pseudoexfoliation syndrome-associated genetic variants affect transcription factor binding and alternative splicing of LOXL1."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "It is thought to be caused by the obstruction of the aqueous humour outflow pathways because of the deposition of extracellular protein aggregates leading to intraocular pressure elevation and subsequent glaucomatous optic nerve damage."
    explanation: >-
      The same chain stated in the introduction of the functional-genetics
      paper; OTHER because the sentence is background synthesis rather than a
      result of the study.
  downstream:
  - target: Elevated Intraocular Pressure
    causal_link_type: DIRECT
    description: >-
      Rising outflow resistance raises intraocular pressure. As in pigment
      dispersion, the edge fires only in a subset of eyes; a heavily loaded
      angle with normal pressure is common.
    evidence:
    - reference: PMID:28534485
      reference_title: "Pseudoexfoliation syndrome-associated genetic variants affect transcription factor binding and alternative splicing of LOXL1."
      supports: SUPPORT
      evidence_source: OTHER
      snippet: "It is thought to be caused by the obstruction of the aqueous humour outflow pathways because of the deposition of extracellular protein aggregates leading to intraocular pressure elevation and subsequent glaucomatous optic nerve damage."
      explanation: >-
        Obstruction leading to pressure elevation is the edge.
- name: Elevated Intraocular Pressure
  biological_scale: TISSUE
  description: >-
    Sustained rise in intraocular pressure as outflow resistance outstrips
    compensation. The pressure in exfoliation eyes is characteristically
    higher, more labile and more prone to spikes than in primary open-angle
    glaucoma, so that a single office reading underestimates the exposure; in
    newly diagnosed high-pressure exfoliation patients the untreated 24-hour
    mean pressure sits above 30 mmHg. It is the node that carries the chain to
    the optic nerve and the only one current treatment acts on.
  conforms_to: "glaucoma_optic_neuropathy#Elevated Intraocular Pressure"
  evidence:
  - reference: PMID:18028119
    reference_title: "Pseudoexfoliation in the Reykjavik Eye Study: prevalence and related ophthalmological variables."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Eyes with PEX were found to have higher intraocular pressure (IOP) than eyes without PEX (p < 0.05)."
    explanation: >-
      Population-based confirmation that the syndrome, before any glaucoma
      diagnosis, raises pressure.
  - reference: PMID:23686322
    reference_title: "24-hour efficacy of the bimatoprost-timolol fixed combination versus latanoprost as first choice therapy in subjects with high-pressure exfoliation syndrome and glaucoma."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "At baseline, mean untreated 24-h IOP was 31.1 mm Hg."
    explanation: >-
      The magnitude of untreated pressure in the high-pressure exfoliation
      population, from a 24-hour curve rather than a single reading.
  - reference: PMID:39458082
    reference_title: "Postoperative Outcomes of PreserFlo MicroShunt in Patients with Exfoliation Glaucoma."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "Exfoliation glaucoma presents a risk of higher IOP and a more rapid progression of visual field defects"
    explanation: >-
      The higher-pressure, faster-course character of this glaucoma, stated as
      background in a surgical series; OTHER because it is synthesis rather
      than a result.
  downstream:
  - target: Retinal Ganglion Cell Apoptosis
    causal_link_type: DIRECT
    description: >-
      Sustained pressure elevation stresses the optic nerve head and drives
      ganglion cell death, the conserved module step.
  - target: Ocular hypertension
    causal_link_type: DIRECT
    description: >-
      The measurable clinical sign of this node.
- name: Lamina Cribrosa Elastosis
  biological_scale: TISSUE
  description: >-
    The node that is specific to this disease within the glaucoma arm. The
    connective tissue of the lamina cribrosa in exfoliation glaucoma shows
    marked, widespread elastosis, with large irregular elastin-positive
    aggregates interspersed with microfibrils and without typical exfoliation
    fibres, and the elastosis is greater than in primary open-angle glaucoma
    and absent from the retrolaminar nerve. It is the leading structural
    explanation for why these optic nerves progress faster at a given pressure,
    but that step, from elastotic lamina to heightened pressure vulnerability,
    is an inference and is curated as one.
  locations:
  - preferred_term: lamina cribrosa
    term:
      id: UBERON:0035966
      label: scleral lamina cribrosa
  evidence:
  - reference: PMID:7777294
    reference_title: "Elastosis of the lamina cribrosa in pseudoexfoliation syndrome with glaucoma."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "In all eyes with pseudoexfoliation and glaucoma, there was marked and widespread elastosis in the connective tissue of the lamina cribrosa."
    explanation: >-
      The observation that defines the node.
  - reference: PMID:7777294
    reference_title: "Elastosis of the lamina cribrosa in pseudoexfoliation syndrome with glaucoma."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "In contrast, there were less elastotic fibers in the lamina cribrosa from patients with primary open-angle glaucoma compared with pseudoexfoliation glaucoma."
    explanation: >-
      The comparison with primary open-angle glaucoma that makes this a
      disease-specific finding rather than a generic glaucomatous change.
  downstream:
  - target: Retinal Ganglion Cell Apoptosis
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    description: >-
      An elastotic, mechanically abnormal lamina is proposed to transmit
      pressure to the ganglion cell axons less protectively, contributing to the
      faster course. Hypothesis, not demonstration; the knowledge gap below
      records it.
- name: Retinal Ganglion Cell Apoptosis
  biological_scale: CELLULAR
  description: >-
    Pressure-related stress at the optic nerve head drives apoptotic loss of
    retinal ganglion cells, the conserved effector step of every glaucoma. The
    entry adds nothing disease-specific at this node beyond the two upstream
    inputs, higher and more labile pressure and an elastotic lamina; the
    cellular biology is the module's.
  conforms_to: "glaucoma_optic_neuropathy#Retinal Ganglion Cell Apoptosis"
  cell_types:
  - preferred_term: retinal ganglion cell
    term:
      id: CL:0000740
      label: retinal ganglion cell
  biological_processes:
  - preferred_term: retinal ganglion cell apoptosis
    modifier: INCREASED
    term:
      id: GO:0051402
      label: neuron apoptotic process
  evidence:
  - reference: PMID:28534485
    reference_title: "Pseudoexfoliation syndrome-associated genetic variants affect transcription factor binding and alternative splicing of LOXL1."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "It represents a neurodegenerative disease complex comprising heterogeneous subtypes that share a common pathogenic pathway, that is, progressive loss of retinal ganglion cells and optic nerve axons resulting in visual field defects."
    explanation: >-
      The shared final pathway of glaucoma, of which exfoliation glaucoma is
      named as the frequent, progressive subtype. OTHER because the sentence is
      background synthesis.
  downstream:
  - target: Exfoliation Glaucoma Optic Neuropathy
    causal_link_type: DIRECT
    description: >-
      Cumulative ganglion cell and axon loss produces the disc cupping and
      field loss that make the diagnosis.
- name: Exfoliation Glaucoma Optic Neuropathy
  biological_scale: TISSUE
  description: >-
    The point at which the diagnosis changes name. Exfoliation glaucoma is the
    commonest identifiable cause of secondary open-angle glaucoma worldwide,
    accounting for roughly a quarter of open-angle glaucoma, and it is a worse
    disease than primary open-angle glaucoma: pressures are higher, medical
    control is poorer, laser and surgery are needed more often, and the visual
    field deteriorates faster. Conversion is substantial but far from
    universal, which is what makes the syndrome a risk state rather than a
    glaucoma: about 44% of newly diagnosed patients in a community cohort
    reached treatment within 15 years, and among ocular hypertensives the
    syndrome doubled the conversion rate to perimetric glaucoma at matched
    pressure.
  conforms_to: "glaucoma_optic_neuropathy#Progressive Glaucomatous Optic Neuropathy"
  cell_types:
  - preferred_term: retinal ganglion cell
    term:
      id: CL:0000740
      label: retinal ganglion cell
  evidence:
  - reference: PMID:15745763
    reference_title: "Risk of glaucoma in ocular hypertension with and without pseudoexfoliation."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "After a mean of 8.7 years (range: 6.3-11.4), 54 of 98 patients (55.1%) with pseudoexfoliation at the baseline examination and 27 of 98 patients (27.6%) without pseudoexfoliation had developed glaucoma."
    explanation: >-
      At matched pressure, age and sex, the syndrome doubled conversion to
      glaucoma, which is the strongest evidence that something beyond pressure,
      such as the elastotic lamina, is at work.
  - reference: PMID:17986292
    reference_title: "Incidence and prevalence of pseudoexfoliations and open-angle glaucoma in northern Sweden: II. Results after 21 years of follow-up."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "PEX increased the risk of glaucoma four fold in both sexes."
    explanation: >-
      The population-level risk, from a 21-year prospective cohort.
  - reference: PMID:28553957
    reference_title: "Genetic association study of exfoliation syndrome identifies a protective rare variant at LOXL1 and five new susceptibility loci."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "Exfoliation glaucoma (XFG) has a worse prognosis than other major types of glaucoma, and it is often resistant to intraocular pressure-lowering medical treatment"
    explanation: >-
      The worse prognosis and poorer medical response that distinguish this
      glaucoma; OTHER because the sentence is the paper's background synthesis.
  - reference: PMID:29547474
    reference_title: "Exfoliation Syndrome: A Disease of Autophagy and LOXL1 Proteopathy."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "Worldwide, XFG accounts for about 25% of open-angle glaucoma cases."
    explanation: >-
      The share of open-angle glaucoma attributable to this disease.
  downstream:
  - target: Open angle glaucoma
    causal_link_type: DIRECT
    description: >-
      Glaucomatous optic neuropathy with an open angle is the diagnostic
      threshold, not a separate biological step.
  - target: Visual field defect
    causal_link_type: DIRECT
    description: >-
      Ganglion cell loss produces the characteristic field defects, which
      progress faster here than in primary open-angle glaucoma.
  - target: Visual impairment
    causal_link_type: DIRECT
    description: >-
      Advanced, often late-recognised optic neuropathy is the main route to
      irreversible visual loss in this disease.
- name: Systemic Elastosis
  biological_scale: ORGANISM
  description: >-
    Aggregates consistent with exfoliation material are present in the lung,
    heart, liver, gallbladder and skin of affected people, in fibrovascular
    septa adjacent to elastic and oxytalan fibres, staining for elastin and
    amyloid P like the ocular deposits. This is the histological basis for
    calling the syndrome systemic, and it explains why the systemic
    associations were looked for. Whether it produces disease outside the eye
    is a different question: the cardiovascular, cerebrovascular, hearing and
    pelvic-floor associations recorded below are epidemiological, are
    susceptible to the confounding of an elderly population, and are curated
    as associations with the gap left open.
  locations:
  - preferred_term: skin
    term:
      id: UBERON:0002097
      label: skin of body
  - preferred_term: heart
    term:
      id: UBERON:0000948
      label: heart
  - preferred_term: lung
    term:
      id: UBERON:0002048
      label: lung
  evidence:
  - reference: PMID:1463419
    reference_title: "Pseudoexfoliative fibrillopathy in visceral organs of a patient with pseudoexfoliation syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Aggregates consistent with pseudoexfoliative material were present in the lung, heart, liver, and gallbladder, in addition to the classic intraocular sites."
    explanation: >-
      The autopsy demonstration of visceral deposits, a single case but the
      one that established the systemic concept.
  - reference: PMID:26307087
    reference_title: "Genetic variants and cellular stressors associated with exfoliation syndrome modulate promoter activity of a lncRNA within the LOXL1 locus."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "Exfoliation syndrome (XFS) is a common, age-related, systemic fibrillinopathy."
    explanation: >-
      The systemic framing as now standard; OTHER because the sentence is the
      paper's opening synthesis rather than its result.
  downstream:
  - target: Abnormality of the cardiovascular system
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    description: >-
      Meta-analysis finds a 1.6-fold odds of cardiovascular disease with the
      syndrome. The edge is drawn because vascular elastic tissue is a site of
      deposition, but no intermediate has been demonstrated and confounding is
      not excluded.
  - target: Sensorineural hearing impairment
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    description: >-
      Hearing thresholds exceed age norms in most affected patients; the
      proposed intermediate is deposition in the inner ear, which has not been
      shown.
  - target: Pelvic organ prolapse
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    description: >-
      The most mechanistically coherent association, because Loxl1-null mice
      develop pelvic organ prolapse from failed elastic fibre maintenance; in
      humans it is a population-database association only.
phenotypes:
- name: Pseudoexfoliation
  category: Ophthalmic
  frequency: OBLIGATE
  description: >-
    White-grey fibrillar deposits on the anterior lens capsule and pupillary
    border, the most consistent and important diagnostic feature of the
    disease. The classic capsular pattern, a central disc, a clear intermediate
    zone scoured by the moving iris, and a granular peripheral ring, is seen
    only when the pupil is fully dilated, which is why undilated examination
    misses the diagnosis. Early, pre-classic stages are poorly defined.
  phenotype_term:
    preferred_term: Exfoliation material on the anterior lens capsule and pupillary border
    term:
      id: HP:0012627
      label: Pseudoexfoliation
  diagnostic: true
  evidence:
  - reference: PMID:11166342
    reference_title: "Exfoliation syndrome."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "Deposits of white material on the anterior lens surface are the most consistent and important diagnostic feature of XFS."
    explanation: >-
      Establishes the deposits as the defining, diagnostic sign, which is the
      basis for the OBLIGATE frequency.
  - reference: PMID:11166342
    reference_title: "Exfoliation syndrome."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "The classic pattern consists of three distinct zones that become visible when the pupil is fully dilated."
    explanation: >-
      The three-zone pattern and the need for dilation to see it.
- name: Iris transillumination defect
  category: Ophthalmic
  description: >-
    Peripupillary transillumination from loss of the iris pigment epithelium
    at the sphincter region, in a distribution that distinguishes it from the
    mid-peripheral radial spokes of pigment dispersion syndrome.
  phenotype_term:
    preferred_term: Peripupillary iris transillumination defect
    term:
      id: HP:0012805
      label: Iris transillumination defect
  evidence:
  - reference: PMID:38304644
    reference_title: "Cardiovascular Manifestations of Pseudoexfoliation Syndrome: A Narrative Review."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "Symptoms of PEX include elevated intraocular pressure, peripapillary transillumination deficiencies, potential glaucomatous optic nerve damage, poor dilatation, Sampaolesi line, and fibrillar white flaky deposits along the pupillary border."
    explanation: >-
      Names transillumination defects among the cardinal signs. Quoted
      verbatim; the source writes "peripapillary" where peripupillary is meant.
  - reference: PMID:11166342
    reference_title: "Exfoliation syndrome."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "Pigment loss from the iris sphincter region and its deposition on anterior chamber structures is a hallmark of XFS."
    explanation: >-
      The pigment loss at the sphincter region is what transilluminates.
- name: Poor pupillary dilation
  category: Ophthalmic
  description: >-
    Poor response to pharmacological mydriasis from iris sphincter and stromal
    involvement. A minor sign in the clinic and a major one in the operating
    theatre, where a small pupil combines with zonular laxity to make cataract
    surgery hazardous; it is also why the capsular deposits are easily missed.
  phenotype_term:
    preferred_term: Poor pharmacological mydriasis
  notes: >-
    Left unbound. HPO has Mydriasis (HP:0011499) and Miosis (HP:0000616), but
    no term for impaired pharmacological dilation of an otherwise normal-sized
    pupil, and Abnormal pupil morphology (HP:0000615) would misdescribe a
    functional finding.
  evidence:
  - reference: PMID:38304644
    reference_title: "Cardiovascular Manifestations of Pseudoexfoliation Syndrome: A Narrative Review."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "Symptoms of PEX include elevated intraocular pressure, peripapillary transillumination deficiencies, potential glaucomatous optic nerve damage, poor dilatation, Sampaolesi line, and fibrillar white flaky deposits along the pupillary border."
    explanation: >-
      Names poor dilatation among the cardinal signs.
  - reference: PMID:19465298
    reference_title: "Pseudoexfoliation and the cataract surgeon: preoperative, intraoperative, and postoperative issues related to intraocular pressure, cataract, and intraocular lenses."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "Cataracts occur with increased frequency in PXF eyes, and surgery is potentially complicated by the presence of small pupils and zonule laxity and significantly affects IOP in these eyes."
    explanation: >-
      The surgical consequence of the small pupil.
- name: Pigment deposition in the trabecular meshwork
  category: Ophthalmic
  description: >-
    Patchy, often asymmetric trabecular hyperpigmentation with a wavy pigment
    line anterior to Schwalbe's line (Sampaolesi line) on gonioscopy, from
    dispersed iris pigment. Its presence says pigment has reached the drain,
    not that the drain has failed.
  phenotype_term:
    preferred_term: Trabecular hyperpigmentation with Sampaolesi line
    term:
      id: HP:0012631
      label: Pigment deposition in the trabecular meshwork
  evidence:
  - reference: PMID:38304644
    reference_title: "Cardiovascular Manifestations of Pseudoexfoliation Syndrome: A Narrative Review."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "Symptoms of PEX include elevated intraocular pressure, peripapillary transillumination deficiencies, potential glaucomatous optic nerve damage, poor dilatation, Sampaolesi line, and fibrillar white flaky deposits along the pupillary border."
    explanation: >-
      Names the Sampaolesi line, the gonioscopic signature of the dispersed
      pigment.
- name: Ocular hypertension
  category: Ophthalmic
  description: >-
    Raised intraocular pressure from trabecular obstruction, characteristically
    higher and more labile than in primary open-angle glaucoma. Because the
    pressure fluctuates, a single normal reading does not exclude it.
  phenotype_term:
    preferred_term: Ocular hypertension
    term:
      id: HP:0007906
      label: Ocular hypertension
  evidence:
  - reference: PMID:18028119
    reference_title: "Pseudoexfoliation in the Reykjavik Eye Study: prevalence and related ophthalmological variables."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Eyes with PEX were found to have higher intraocular pressure (IOP) than eyes without PEX (p < 0.05)."
    explanation: >-
      Population-based association of the syndrome with higher pressure.
  - reference: PMID:17224761
    reference_title: "The risk of glaucoma in pseudoexfoliation syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The strongest risk factors for converting to therapy were IOP at initial diagnosis of PEX and bilateral involvement."
    explanation: >-
      Pressure at diagnosis is the strongest predictor of needing treatment,
      which is why this phenotype is the one to follow.
- name: Open angle glaucoma
  category: Ophthalmic
  frequency: FREQUENT
  description: >-
    Exfoliation glaucoma, the secondary open-angle glaucoma that develops in a
    large minority of affected eyes and the commonest identifiable cause of
    secondary open-angle glaucoma worldwide. It runs a more serious course than
    primary open-angle glaucoma, with higher pressures, poorer medical control
    and faster field loss. The frequency band rests on the upper estimate of
    44% of affected eyes; conversion varies widely by population and follow-up.
  phenotype_term:
    preferred_term: Exfoliation glaucoma
    term:
      id: HP:0012108
      label: Open angle glaucoma
  evidence:
  - reference: PMID:23157966
    reference_title: "Pseudoexfoliation syndrome, a systemic disorder with ocular manifestations."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "Pseudoexfoliation is the most common cause of secondary open-angle glaucoma (pseudoexfoliation glaucoma, PXG) worldwide."
    explanation: >-
      Defines the phenotype as a secondary open-angle glaucoma and gives its
      global standing.
  - reference: PMID:35348588
    reference_title: "RNA Sequencing of Lens Capsular Epithelium Implicates Novel Pathways in Pseudoexfoliation Syndrome."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "Secondary open-angle glaucoma, which occurs in up to 44% of PEX-affected eyes"
    explanation: >-
      The proportion of affected eyes that develop glaucoma, supporting the
      FREQUENT band (30-79%). OTHER because it is the paper's background
      synthesis, not its result.
  - reference: PMID:17224761
    reference_title: "The risk of glaucoma in pseudoexfoliation syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "In the remaining PEX patients, the probability of being placed on therapy was 44% at 15 years."
    explanation: >-
      A community-based conversion figure consistent with the band; the
      endpoint is treatment for glaucoma or treated ocular hypertension, so it
      slightly overstates glaucoma itself.
  - reference: PMID:11166342
    reference_title: "Exfoliation syndrome."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "Patients with XFS are also predisposed to develop angle-closure glaucoma, and glaucoma in XFS has a more serious clinical course and worse prognosis than primary open-angle glaucoma."
    explanation: >-
      The worse course and prognosis that distinguish this glaucoma.
- name: Angle closure glaucoma
  category: Ophthalmic
  description: >-
    Exfoliation eyes are also predisposed to angle closure, attributed to
    forward movement of a lens on lax zonules together with iris changes. Much
    less common than the open-angle form and easily missed if the open angle
    is assumed.
  phenotype_term:
    preferred_term: Angle closure glaucoma
    term:
      id: HP:0012109
      label: Angle closure glaucoma
  evidence:
  - reference: PMID:11166342
    reference_title: "Exfoliation syndrome."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "Patients with XFS are also predisposed to develop angle-closure glaucoma, and glaucoma in XFS has a more serious clinical course and worse prognosis than primary open-angle glaucoma."
    explanation: >-
      Establishes the angle-closure predisposition.
- name: Visual field defect
  category: Ophthalmic
  description: >-
    Glaucomatous field loss, which progresses faster in exfoliation glaucoma
    than in primary open-angle glaucoma and is often advanced at presentation
    because the syndrome is silent until then.
  phenotype_term:
    preferred_term: Glaucomatous visual field defect
    term:
      id: HP:0007854
      label: Glaucomatous visual field defect
  evidence:
  - reference: PMID:39458082
    reference_title: "Postoperative Outcomes of PreserFlo MicroShunt in Patients with Exfoliation Glaucoma."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "Exfoliation glaucoma presents a risk of higher IOP and a more rapid progression of visual field defects"
    explanation: >-
      Names the faster field progression that characterises this glaucoma.
  - reference: PMID:28534485
    reference_title: "Pseudoexfoliation syndrome-associated genetic variants affect transcription factor binding and alternative splicing of LOXL1."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "It represents a neurodegenerative disease complex comprising heterogeneous subtypes that share a common pathogenic pathway, that is, progressive loss of retinal ganglion cells and optic nerve axons resulting in visual field defects."
    explanation: >-
      Field defects as the functional consequence of ganglion cell loss.
- name: Visual impairment
  category: Ophthalmic
  description: >-
    Irreversible visual loss from advanced exfoliation glaucoma, and reversible
    loss from cataract. The disease is a major cause of blindness worldwide by
    virtue of its prevalence and the severity of its glaucoma.
  phenotype_term:
    preferred_term: Visual impairment
    term:
      id: HP:0000505
      label: Visual impairment
  evidence:
  - reference: PMID:28553957
    reference_title: "Genetic association study of exfoliation syndrome identifies a protective rare variant at LOXL1 and five new susceptibility loci."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Exfoliation syndrome (XFS) is the most common known risk factor for secondary glaucoma and a major cause of blindness worldwide."
    explanation: >-
      The blindness burden, stated by the largest genetic study of the disease.
- name: Phakodonesis
  category: Ophthalmic
  description: >-
    Tremulousness of the lens with eye movement, the clinical sign of zonular
    weakness and a warning of surgical difficulty.
  phenotype_term:
    preferred_term: Phacodonesis
    term:
      id: HP:0012629
      label: Phakodonesis
  evidence:
  - reference: PMID:7977599
    reference_title: "A histopathologic study of zonular instability in pseudoexfoliation syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "A weak zonular apparatus has been postulated to account for the high incidence of phacodonesis, lens dislocation, and vitreous complications during extracapsular cataract surgery in eyes with pseudoexfoliation syndrome."
    explanation: >-
      Names phacodonesis as a frequent consequence of the zonular weakness
      the paper then demonstrates.
- name: Lens subluxation
  category: Ophthalmic
  description: >-
    Displacement of the crystalline lens, or late dislocation of the
    intraocular lens and capsular bag together years after cataract surgery,
    from progressive zonular loss. Spontaneous late-onset subluxation is one of
    the recognised ocular consequences of the syndrome.
  phenotype_term:
    preferred_term: Lens subluxation or dislocation
    term:
      id: HP:0001132
      label: Lens subluxation
  evidence:
  - reference: PMID:7977599
    reference_title: "A histopathologic study of zonular instability in pseudoexfoliation syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "A weak zonular apparatus has been postulated to account for the high incidence of phacodonesis, lens dislocation, and vitreous complications during extracapsular cataract surgery in eyes with pseudoexfoliation syndrome."
    explanation: >-
      Names lens dislocation among the consequences of zonular weakness.
  - reference: PMID:35348588
    reference_title: "RNA Sequencing of Lens Capsular Epithelium Implicates Novel Pathways in Pseudoexfoliation Syndrome."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "Cataract surgery in PEX is associated with higher intraoperative complication rates owing to zonular instability, lens dislocation, impaired pupillary dilation, and increased postoperative complication rates owing to corneal decompensation, IOP spikes, and posterior capsular opacification"
    explanation: >-
      Lens dislocation among the surgical complications attributed to zonular
      instability; OTHER because it is the paper's background synthesis.
- name: Cataract
  category: Ophthalmic
  description: >-
    Age-related cataract occurs with increased frequency in affected eyes, with
    Australian population data showing twice the prevalence of nuclear cataract.
    It is the main reversible cause of visual loss in the disease, and its
    surgery is where the zonular and pupillary phenotypes exact their price.
  phenotype_term:
    preferred_term: Nuclear cataract
    term:
      id: HP:0000518
      label: Cataract
  evidence:
  - reference: PMID:19465298
    reference_title: "Pseudoexfoliation and the cataract surgeon: preoperative, intraoperative, and postoperative issues related to intraocular pressure, cataract, and intraocular lenses."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "Cataracts occur with increased frequency in PXF eyes, and surgery is potentially complicated by the presence of small pupils and zonule laxity and significantly affects IOP in these eyes."
    explanation: >-
      The increased cataract frequency and its surgical implications.
  - reference: PMID:35348588
    reference_title: "RNA Sequencing of Lens Capsular Epithelium Implicates Novel Pathways in Pseudoexfoliation Syndrome."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "Australian epidemiological data demonstrating that PEX-affected eyes have twice the prevalence of nuclear cataract"
    explanation: >-
      The quantitative excess of nuclear cataract; OTHER because the sentence
      is the paper's background synthesis of a cited cohort.
- name: Abnormality of the cardiovascular system
  category: Systemic
  description: >-
    Cardiovascular and cerebrovascular disease (myocardial infarction, stroke,
    transient ischaemic attack, systemic hypertension, aortic aneurysm,
    cardiomyopathy) are reported more often in people with the syndrome, with a
    meta-analytic odds ratio of about 1.6 for cardiovascular disease and 1.8
    for cerebrovascular disease. The association is consistent across
    sensitivity analyses but rests on observational studies in an elderly
    population, publication bias is detectable for the cerebrovascular
    outcome, and no mechanism has been demonstrated. Recorded as an
    association; it is not established that the syndrome causes vascular
    disease, and screening beyond age-appropriate care is not justified by it.
  phenotype_term:
    preferred_term: Cardiovascular and cerebrovascular disease (association)
    term:
      id: HP:0001626
      label: Abnormality of the cardiovascular system
  evidence:
  - reference: PMID:30119791
    reference_title: "Association of pseudoexfoliation syndrome with cardiovascular and cerebrovascular disease: a systematic review and meta-analysis."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Twenty studies enrolling 9583 individuals with PEX evaluated CVD, providing a summary odds ratio (OR) of 1.61 (95% CI 1.37-1.90)."
    explanation: >-
      The pooled association for cardiovascular disease.
  - reference: PMID:30119791
    reference_title: "Association of pseudoexfoliation syndrome with cardiovascular and cerebrovascular disease: a systematic review and meta-analysis."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Analysis for publication bias with the Egger's test was not significant for studies reporting CVD and AVE (p = 0.92 and 0.64, respectively) but was significant for CVA (p = 0.03)."
    explanation: >-
      The publication-bias caveat that keeps this an association rather than a
      finding; cited so the weakness of the cerebrovascular signal is on the
      record.
  - reference: PMID:11166342
    reference_title: "Exfoliation syndrome."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "XFS is now suspected to be a systemic disorder and has been associated preliminarily with transient ischemic attacks, stroke, systemic hypertension, and myocardial infarction."
    explanation: >-
      The associations as first described, in language ("suspected",
      "preliminarily") that this entry keeps.
- name: Sensorineural hearing impairment
  category: Systemic
  description: >-
    Hearing thresholds above the age- and sex-matched ISO 7029 median in about
    three quarters of ears in one clinic series, regardless of glaucoma and
    regardless of which eye carried the deposits. A single uncontrolled series;
    the proposed inner-ear deposition has not been shown.
  phenotype_term:
    preferred_term: Sensorineural hearing loss (association)
    term:
      id: HP:0000407
      label: Sensorineural hearing impairment
  evidence:
  - reference: PMID:12032714
    reference_title: "Pseudoexfoliation and sensorineural hearing loss."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "A large proportion of patients with PXF have sensorineural hearing loss in comparison to age-matched controls, regardless of whether or not there is associated glaucoma."
    explanation: >-
      The finding as the authors state it.
  - reference: PMID:12032714
    reference_title: "Pseudoexfoliation and sensorineural hearing loss."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "There was no significant difference between the proportion of ears with HTL1,2,3 higher than the ISO 7029 median AAHL1,2,3 on the same side as eyes without PXF, with PXF but not glaucoma and with PXF and glaucoma, in either the male or female groups."
    explanation: >-
      Hearing loss did not track the affected eye, which argues for a systemic
      rather than a local process, and equally leaves confounding open.
- name: Pelvic organ prolapse
  category: Systemic
  description: >-
    Women with pelvic organ prolapse had 1.5-fold the odds of exfoliation
    syndrome in Utah Medicare data and a 48% higher incidence over 20 years of
    follow-up. Of the systemic associations this is the most mechanistically
    coherent, because failed elastic fibre maintenance in Loxl1-null mice
    produces exactly this phenotype, but in humans it remains an association
    in a population database.
  phenotype_term:
    preferred_term: Pelvic organ prolapse (association)
    term:
      id: HP:0031607
      label: Pelvic organ prolapse
  evidence:
  - reference: PMID:27632406
    reference_title: "Risk for Exfoliation Syndrome in Women With Pelvic Organ Prolapse : A Utah Project on Exfoliation Syndrome (UPEXS) Study."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Pelvic organ prolapse was associated with a 1.56-fold increased risk of exfoliation syndrome in Medicare beneficiaries (OR, 1.56; 95% CI, 1.42-1.72) in substudy A."
    explanation: >-
      The cross-sectional association.
  - reference: PMID:27632406
    reference_title: "Risk for Exfoliation Syndrome in Women With Pelvic Organ Prolapse : A Utah Project on Exfoliation Syndrome (UPEXS) Study."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Systemic conditions with altered ECM metabolism, such as pelvic organ prolapse, may share common biological pathways with exfoliation syndrome."
    explanation: >-
      The authors' interpretation, hedged as a shared pathway rather than a
      cause.
genetic:
- name: LOXL1
  gene_term:
    preferred_term: LOXL1
    term:
      id: hgnc:6665
      label: LOXL1
  relationship_type: SUSCEPTIBILITY
  notes: >-
    Lysyl oxidase-like 1, the cross-linking enzyme of elastic fibre formation
    and the principal susceptibility locus. Two common exon 1 coding variants
    (rs1048661 p.Arg141Leu, rs3825942 p.Gly153Asp) and the intronic rs2165241
    carry a population attributable risk above 99% in Nordic populations; a
    regulatory variant spanning introns 1 and 2 (rs11638944) alters RXR-alpha
    binding and splicing and lowers LOXL1 mRNA in risk-allele carriers;
    risk alleles in the LOXL1-AS1 promoter region modulate that lncRNA's
    stress-responsive promoter; and a rare coding allele, p.Phe407, is
    protective with an odds ratio of 25. The reason for SUSCEPTIBILITY rather
    than CAUSATIVE is the allele reversal: the rs3825942 G allele is the risk
    allele in Europeans, Japanese, Koreans, Chinese, South Asians and Middle
    Easterners but protective in black South Africans, and rs1048661 G is a
    risk allele in Europeans but protective in Japanese and Koreans. The
    functional variants are therefore elsewhere in the locus and are tagged
    differently in different ancestries. Deliberately not typed CAUSATIVE:
    four fifths of unaffected people carry the risk variants, the risk allele
    flips between populations, and Loxl1-null mice do not form exfoliation
    material, so the gene sets susceptibility and does not by itself cause the
    disease.
  evidence:
  - reference: PMID:17690259
    reference_title: "Common sequence variants in the LOXL1 gene confer susceptibility to exfoliation glaucoma."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Two nonsynonymous SNPs in exon 1 of the gene LOXL1 explain the association, and the data suggest that they confer risk of XFG mainly through exfoliation syndrome (XFS)."
    explanation: >-
      The original association.
  - reference: PMID:20431720
    reference_title: "Major LOXL1 risk allele is reversed in exfoliation glaucoma in a black South African population."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The A allele of rs3825942 (encoding aspartic acid) was the risk allele, in sharp contrast to the G allele (encoding glycine) reported in multiple other populations."
    explanation: >-
      The allele reversal, which is the single strongest argument that the
      coding variants tag rather than cause.
  - reference: PMID:26404116
    reference_title: "Ethnicity-Based Differences in the Association of LOXL1 Polymorphisms with Pseudoexfoliation/Pseudoexfoliative Glaucoma: A Meta-Analysis."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Rs3825942 (G) was an at risk allele for PEX/PEXG in Caucasians, Japanese, Koreans, Chinese, South Asians, and Middle Easterners, but protective in Black South Africans (OR = 0.10, 95%CI:0.06-0.16)."
    explanation: >-
      The reversal confirmed across 39 cohorts by meta-analysis.
  - reference: PMID:28534485
    reference_title: "Pseudoexfoliation syndrome-associated genetic variants affect transcription factor binding and alternative splicing of LOXL1."
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: "We find that the rs11638944:C>G transversion exerts a cis-acting effect on the expression levels of LOXL1, mediated by differential binding of the transcription factor RXRα (retinoid X receptor alpha) and by modulating alternative splicing of LOXL1, eventually leading to reduced levels of LOXL1 mRNA in cells and tissues of risk allele carriers."
    explanation: >-
      The functional regulatory variant.
  - reference: PMID:28553957
    reference_title: "Genetic association study of exfoliation syndrome identifies a protective rare variant at LOXL1 and five new susceptibility loci."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "We identified a rare protective allele at LOXL1 (p.Phe407, odds ratio (OR) = 25, P = 2.9 × 10-14) through deep resequencing of XFS cases and controls from nine countries."
    explanation: >-
      The protective rare allele.
  - reference: PMID:33909695
    reference_title: "LOXL1 gene polymorphisms are associated with exfoliation syndrome/exfoliation glaucoma risk: An updated meta-analysis."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "In total, 5022 cases and 8962 controls were included in this meta-analysis."
    explanation: >-
      The scale of the replication behind the association, from the 2021
      meta-analysis the deep-research report leads with.
- name: CACNA1A
  gene_term:
    preferred_term: CACNA1A
    term:
      id: hgnc:1388
      label: CACNA1A
  relationship_type: SUSCEPTIBILITY
  notes: >-
    The P/Q-type calcium channel alpha-1A subunit, the second locus found by
    genome-wide association and confirmed in the 2017 international
    meta-analysis. Its route to a matrix phenotype is not established; it is
    recorded as a locus, not a mechanism.
  evidence:
  - reference: PMID:28553957
    reference_title: "Genetic association study of exfoliation syndrome identifies a protective rare variant at LOXL1 and five new susceptibility loci."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Variants in two genes, LOXL1 and CACNA1A, have previously been associated with XFS."
    explanation: >-
      Names CACNA1A as the second established locus.
- name: Additional genome-wide susceptibility loci
  relationship_type: SUSCEPTIBILITY
  notes: >-
    Five further genome-wide significant loci from the 2017 study of 9,035
    cases and 17,008 controls: 13q12 (POMP, proteasome maturation), 11q23.3
    (TMEM136), 6p21 (AGPAT1), 3p24 (RBMS3) and 5q23 (near SEMA6A). Each is a
    modest-effect common locus; none is bound to a gene here because the
    association is with a region and the causal gene at most of them is
    unresolved.
  evidence:
  - reference: PMID:28553957
    reference_title: "Genetic association study of exfoliation syndrome identifies a protective rare variant at LOXL1 and five new susceptibility loci."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "We identified association signals at 13q12 (POMP), 11q23.3 (TMEM136), 6p21 (AGPAT1), 3p24 (RBMS3) and 5q23 (near SEMA6A)."
    explanation: >-
      The five loci, reported as regions with the nearest gene.
- name: CYP39A1
  gene_term:
    preferred_term: CYP39A1
    term:
      id: hgnc:17449
      label: CYP39A1
  relationship_type: RISK_FACTOR
  notes: >-
    Rare damaging coding variants in the oxysterol 7-alpha-hydroxylase CYP39A1
    are enriched in cases by whole-exome sequencing across 14 countries (odds
    ratio 3.55 in discovery, 1.82 in validation), most are functionally
    deficient in biochemical assay, and CYP39A1 transcript is reduced by about
    half in affected ciliary body. The first rare-variant risk gene for the
    disease and a lead toward a role for sterol metabolism; carried by a small
    minority of patients.
  evidence:
  - reference: PMID:33620406
    reference_title: "Association of Rare CYP39A1 Variants With Exfoliation Syndrome Involving the Anterior Chamber of the Eye."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "In the discovery cohort, persons with exfoliation syndrome, compared with those without exfoliation syndrome, were significantly more likely to carry damaging CYP39A1 variants (1.3% vs 0.30%, respectively; odds ratio, 3.55 [95% CI, 2.07-6.10]; P = 6.1 × 10-7)."
    explanation: >-
      The discovery association, with the carrier frequencies that show how
      small the affected minority is.
  - reference: PMID:33620406
    reference_title: "Association of Rare CYP39A1 Variants With Exfoliation Syndrome Involving the Anterior Chamber of the Eye."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "CYP39A1 transcript expression was 47% lower (95% CI, 30%-64% lower; P < .001) in ciliary body tissues from individuals with exfoliation syndrome compared with individuals without exfoliation syndrome."
    explanation: >-
      Reduced expression in the tissue that produces exfoliation material,
      which is what connects the genetic finding to the mechanism.
environmental:
- name: Lifetime solar exposure and reflected light
  description: >-
    Lifetime residential latitude away from the equator, hours spent outdoors
    in summer, and work over water or snow are each associated with the
    syndrome in a clinic-based case-control study in the United States and
    Israel, and sunglass use was protective in the United States arm. A history
    of non-melanoma skin cancer, as a marker of cumulative ultraviolet
    exposure, carried a 40% higher risk of exfoliation glaucoma in 120,000
    health-professional cohort participants. Together with the ability of
    ultraviolet light to induce LOXL1 and elastic proteins in culture, this is
    the best-supported environmental contributor, though a gene-environment
    interaction with LOXL1 has been proposed and not confirmed.
  exposure_term:
    preferred_term: ocular exposure to ultraviolet and reflected sunlight
    term:
      id: ECTO:0000006
      label: exposure to ultraviolet radiation
  evidence:
  - reference: PMID:25188364
    reference_title: "Solar exposure and residential geographic history in relation to exfoliation syndrome in the United States and Israel."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "In multivariable analyses, each degree of weighted lifetime average residential latitude away from the equator was associated with 11% increased odds of XFS (pooled odds ratio [OR], 1.11; 95% CI, 1.05-1.17; P < .001)."
    explanation: >-
      The latitude gradient, with its effect size.
  - reference: PMID:25188364
    reference_title: "Solar exposure and residential geographic history in relation to exfoliation syndrome in the United States and Israel."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The association with work over snow or water and the lack of association with brimmed hat wear suggests that ocular exposure to light from reflective surfaces may be an important type of exposure in XFS etiology."
    explanation: >-
      The specific exposure the pattern points to: light reaching the eye from
      below, which a hat does not block and sunglasses do.
  - reference: PMID:32487970
    reference_title: "Cohort Study of Nonmelanoma Skin Cancer and the Risk of Exfoliation Glaucoma."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "In multivariable-adjusted analyses, we observed a 40% higher XFG risk with any NMSC history (MVRR=1.40; 95% CI=1.08-1.82); the association was observed even with 4 and 8-year lags in NMSC history."
    explanation: >-
      Prospective cohort support using a proxy for cumulative ultraviolet
      exposure.
  - reference: PMID:25171642
    reference_title: "Consideration for gene-environment interactions as novel determinants of exfoliation syndrome."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "It should be stated at the outset that GxE interactions for XFS have not been confirmed but several are suspected."
    explanation: >-
      Records the honest status of the gene-environment interaction: suspected,
      not confirmed.
  influences_mechanisms:
  - target: TGF-beta1 Excess and Oxidative Stress in the Anterior Segment
    environmental_effect: PREDISPOSES
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    description: >-
      Ultraviolet light induces LOXL1 and elastic fibre proteins in cultured
      fibroblasts alongside TGF-beta1 and oxidative stress, and reflected
      light reaching the eye is the exposure the epidemiology implicates; the
      in vivo route from light to the anterior-segment stress milieu is not
      demonstrated, hence PREDISPOSES rather than TRIGGERS.
    evidence:
    - reference: PMID:21948647
      reference_title: "Regulation of lysyl oxidase-like 1 (LOXL1) and elastin-related genes by pathogenic factors associated with pseudoexfoliation syndrome."
      supports: SUPPORT
      evidence_source: IN_VITRO
      directness: INDIRECT
      snippet: "Treatment of fibroblasts with TGF-β1, oxidative stress, UV light, and hypoxia induced a significant increase in expression levels of LOXL1 and elastic proteins, whereas the effect of IL-6 was limited to induction of elastic constituents."
      explanation: >-
        Ultraviolet light acts on the same fibrogenic programme as the
        stress milieu; INDIRECT because the experiment is in culture and the
        exposure is applied to fibroblasts rather than to the eye.
treatments:
- name: Topical Intraocular Pressure Lowering Pharmacotherapy
  description: >-
    The pharmacological arm treats pressure, not material: nothing removes
    deposited exfoliation material or restores the meshwork, so this is the
    same topical repertoire as other open-angle glaucomas, applied earlier and
    harder because the pressures are higher and more labile. Prostaglandin
    analogues are first line; in newly diagnosed high-pressure exfoliation
    patients a bimatoprost-timolol fixed combination lowered 24-hour pressure
    more than latanoprost alone, which is the trial evidence that a single
    agent is often not enough here. Medical control fails more often than in
    primary open-angle glaucoma, so laser and surgery are reached sooner.
  therapeutic_modality: SMALL_MOLECULE
  treatment_term:
    preferred_term: Pharmacotherapy
    term:
      id: NCIT:C15986
      label: Pharmacotherapy
    therapeutic_agent:
    - preferred_term: latanoprost
      term:
        id: CHEBI:6384
        label: latanoprost
    - preferred_term: bimatoprost
      term:
        id: CHEBI:51230
        label: bimatoprost
    - preferred_term: timolol
      term:
        id: CHEBI:39465
        label: timolol
  target_mechanisms:
  - target: Elevated Intraocular Pressure
    treatment_effect: INHIBITS
    description: >-
      Lowers pressure by increasing uveoscleral outflow or reducing aqueous
      production, acting around the obstructed meshwork rather than on it.
    evidence:
    - reference: PMID:23686322
      reference_title: "24-hour efficacy of the bimatoprost-timolol fixed combination versus latanoprost as first choice therapy in subjects with high-pressure exfoliation syndrome and glaucoma."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "Mean 24-h IOP with BTFC was significantly lower than with latanoprost (18.9 vs 21.2 mm Hg; p<0.001)."
      explanation: >-
        Both regimens lowered a baseline 24-hour mean of 31.1 mmHg, and the
        combination lowered it further, which is the pressure effect this edge
        records.
  evidence:
  - reference: PMID:23686322
    reference_title: "24-hour efficacy of the bimatoprost-timolol fixed combination versus latanoprost as first choice therapy in subjects with high-pressure exfoliation syndrome and glaucoma."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "As first choice therapy in high-pressure, at-risk exfoliation patients, BTFC controlled mean 24-h IOP significantly better than latanoprost monotherapy."
    explanation: >-
      A randomised crossover comparison in the exfoliation population
      specifically.
  - reference: PMID:28553957
    reference_title: "Genetic association study of exfoliation syndrome identifies a protective rare variant at LOXL1 and five new susceptibility loci."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "Exfoliation glaucoma (XFG) has a worse prognosis than other major types of glaucoma, and it is often resistant to intraocular pressure-lowering medical treatment"
    explanation: >-
      The limitation of the pharmacological arm in this disease.
- name: Selective Laser Trabeculoplasty
  description: >-
    Laser applied to the trabecular meshwork, mechanistically well suited to
    this disease because it targets pigmented trabecular cells and the
    exfoliation meshwork is heavily pigmented. In medically uncontrolled
    exfoliation glaucoma it succeeded in about two fifths of eyes at one year
    and was safe; the effect wanes with time and, as in pigment dispersion, a
    heavily pigmented angle can spike after treatment. A systematic review of
    the randomised trials found no technique clearly superior to another.
  therapeutic_modality: SURGERY
  treatment_term:
    preferred_term: selective laser trabeculoplasty
    term:
      id: NCIT:C15466
      label: Laser Therapy
  target_mechanisms:
  - target: Trabecular Meshwork Obstruction by Exfoliation Material and Pigment
    treatment_effect: INHIBITS
    description: >-
      Acts on the loaded meshwork itself, through a route (biological
      remodelling of trabecular cells rather than removal of material) that
      is not settled.
    evidence:
    - reference: PMID:34634862
      reference_title: "Selective Laser Trabeculoplasty for Medically Uncontrolled Pseudoexfoliation Glaucoma in Korean Patients."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "Selective laser trabeculoplasty (SLT) uses a 532-nm Q-switched, frequency-doubled Nd:YAG laser with nanosecond pulse duration, which selectively targets the pigmented trabecular meshwork without collateral thermal damage to the adjacent non-pigmented trabecular meshwork and underlying trabecular beams"
      explanation: >-
        The laser targets pigmented meshwork specifically, which is why it is
        aimed at this node and why it suits a pigmented exfoliation angle.
  evidence:
  - reference: PMID:34634862
    reference_title: "Selective Laser Trabeculoplasty for Medically Uncontrolled Pseudoexfoliation Glaucoma in Korean Patients."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Based on the Kaplan-Meier survival analysis, the treatment success rate at 12 months after SLT was 41.9% (18 eyes)."
    explanation: >-
      The one-year success rate in medically refractory exfoliation glaucoma,
      modest and honestly reported.
  - reference: PMID:33564134
    reference_title: "Surgical and laser interventions for pseudoexfoliation glaucoma systematic review of randomized controlled trials."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "There are no apparent differences in efficacy and safety, although with large uncertainty, between surgical or laser techniques for PXFG."
    explanation: >-
      The systematic-review verdict that no laser or surgical technique has
      demonstrated superiority in this disease.
- name: Cataract Surgery with Zonular and Pupil Support
  description: >-
    Phacoemulsification in an exfoliation eye is a different operation: the
    pupil is small, the zonules are weak, and zonular dehiscence, capsular
    rupture and vitreous loss are the classic complications. In a 4,535-eye
    registry, zonular weakness needing a capsular tension ring occurred 30
    times and posterior capsular rupture 13 times more often than in other
    eyes, and the procedure cost 1.4 times as much. Iris expansion devices,
    capsular tension rings or hooks, and secure lens fixation are the
    countermeasures; late in-the-bag lens dislocation remains a risk for years.
    Lens extraction also modestly lowers pressure. The surgery addresses the
    cataract and, through the precautions, the zonular phenotype; it does not
    act on any mechanism node.
  therapeutic_modality: SURGERY
  treatment_term:
    preferred_term: phacoemulsification with capsular tension ring or iris expansion device as required
    term:
      id: NCIT:C157809
      label: Cataract Surgery
  target_phenotypes:
  - preferred_term: Cataract
    term:
      id: HP:0000518
      label: Cataract
  notes: >-
    NCIT has no clinical-action term for phacoemulsification or for capsular
    tension ring placement (searched the NCI EVS and OLS on 2026-09-18), so the
    surgery is bound to Cataract Surgery with the technique and adjuncts in
    preferred_term.
  evidence:
  - reference: PMID:38202045
    reference_title: "Pseudoexfoliative Syndrome in Cataract Surgery-A Quality Register Study and Health Economic Analysis in the Split-Dalmatia County, Croatia."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Zonular weakness requiring the use of a capsular tension ring (CTR) and posterior capsular rupture occurred 30 and 13 times more often, respectively, in the PEX group."
    explanation: >-
      The registry-scale quantification of the surgical risk and of the use of
      capsular tension rings to meet it.
  - reference: PMID:19465298
    reference_title: "Pseudoexfoliation and the cataract surgeon: preoperative, intraoperative, and postoperative issues related to intraocular pressure, cataract, and intraocular lenses."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "Preoperative evaluation and the options for intraoperative management of cataract are presented with recommendations for the use of adjunctive pupil and zonule support devices."
    explanation: >-
      The surgical recommendation for pupil and zonule support devices.
  - reference: PMID:11166342
    reference_title: "Exfoliation syndrome."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "The presence of XFS should alert the physician to the increased risks of intraocular surgery, most commonly zonular dehiscence, capsular rupture, and vitreous loss during cataract extraction."
    explanation: >-
      The complications the precautions exist to prevent.
- name: Filtration Surgery
  description: >-
    Trabeculectomy, the reference operation when medication and laser fail,
    which happens more often in this glaucoma than in primary open-angle
    glaucoma. Subconjunctival microshunts and other minimally invasive
    procedures are alternatives; in one exfoliation series a microshunt gave
    roughly 50% success at a year with a 30% reoperation rate, and the
    systematic review of randomised trials could not justify preferring any
    one technique. Filtration bypasses the obstructed meshwork rather than
    clearing it.
  therapeutic_modality: SURGERY
  treatment_term:
    preferred_term: trabeculectomy
    term:
      id: NCIT:C220170
      label: Surgical Construction of Filtration Bleb
  target_mechanisms:
  - target: Elevated Intraocular Pressure
    treatment_effect: BYPASSES
    description: >-
      Creates an alternative drainage route past the obstructed trabecular
      meshwork, lowering pressure without acting on the material.
    evidence:
    - reference: PMID:39458082
      reference_title: "Postoperative Outcomes of PreserFlo MicroShunt in Patients with Exfoliation Glaucoma."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "The postoperative outcomes of the PreserFlo MicroShunt in Asian patients with exfoliation glaucoma demonstrated an approximate 50% success rate at both 24 and 48 weeks, with a reoperation rate of approximately 30%."
      explanation: >-
        A subconjunctival filtration device lowers pressure in this
        population, with the sobering success and reoperation figures that a
        reader should see beside the claim.
  evidence:
  - reference: PMID:33564134
    reference_title: "Surgical and laser interventions for pseudoexfoliation glaucoma systematic review of randomized controlled trials."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Based on the low-quality evidence from the six studies included in this review, it is not possible to justify the preferential use of non-penetrating surgery, MIGS or trabecular aspiration (with or without cataract surgery) in PXFG."
    explanation: >-
      The state of the comparative evidence among surgical options.
  - reference: PMID:28553957
    reference_title: "Genetic association study of exfoliation syndrome identifies a protective rare variant at LOXL1 and five new susceptibility loci."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "Exfoliation glaucoma (XFG) has a worse prognosis than other major types of glaucoma, and it is often resistant to intraocular pressure-lowering medical treatment"
    explanation: >-
      Why surgery is reached more often in this glaucoma.
animal_models:
- name: Loxl1-null mouse
  species: Mouse
  genotype: Loxl1 homozygous null
  publication: PMID:14745449
  description: >-
    The only widely used genetic model, and an instructive failure. Mice
    lacking LOXL1 fail to maintain elastic fibres, with pelvic organ prolapse,
    emphysematous airspaces, loose skin and vascular abnormalities, and in the
    eye show a leaky blood-aqueous barrier, subcapsular lens vesiculation and
    reduced elastin in iris and ciliary body. They do not form exfoliation
    material and they do not develop raised pressure or glaucoma. The model
    therefore reports what LOXL1 loss does to elastic tissue, which is the
    systemic half of the disease, and says nothing about fibrillogenesis,
    which is the ocular half; it is also a loss-of-function model of a disease
    whose human genetics are a regulatory dysregulation.
  modeled_mechanisms:
  - target: Dysregulated LOXL1 Expression and Elastic Microfibril Cross-Linking
    relationship: PARTIALLY_RECAPITULATES
    fidelity: LOW
    model_scale: TISSUE
    description: >-
      Demonstrates that LOXL1 is required for elastic fibre maintenance and
      that its absence produces systemic elastic tissue failure, which is the
      biology this node rests on.
    limitations: >-
      Complete absence of LOXL1 is not the human lesion, which is a
      genotype-dependent and stage-dependent dysregulation of expression with
      excess enzyme early; the model cannot represent the early excess phase
      at all, and the human coding variants do not abolish the protein.
    evidence:
    - reference: PMID:14745449
      reference_title: "Elastic fiber homeostasis requires lysyl oxidase-like 1 protein."
      supports: SUPPORT
      evidence_source: MODEL_ORGANISM
      snippet: "Here we show that mice lacking the protein lysyl oxidase-like 1 (LOXL1) do not deposit normal elastic fibers in the uterine tract post partum and develop pelvic organ prolapse, enlarged airspaces of the lung, loose skin and vascular abnormalities with concomitant tropoelastin accumulation."
      explanation: >-
        The systemic elastic fibre phenotype of the null mouse.
  - target: Exfoliation Material Fibrillogenesis and Deposition
    relationship: FAILS_TO_RECAPITULATE
    fidelity: LOW
    model_scale: TISSUE
    description: >-
      The defining lesion of the human disease does not occur in the model.
    limitations: >-
      Null mice show some anterior-segment features (blood-aqueous barrier
      leak, lens changes, reduced iris and ciliary elastin) but deposit no
      macromolecular material, so the model cannot be used to study how
      exfoliation material forms, what it is made of, or what clears it. The
      authors conclude that complete disease requires factors beyond LOXL1
      loss, which is also what the human genetics say.
    evidence:
    - reference: PMID:24425853
      reference_title: "Disruption of the blood-aqueous barrier and lens abnormalities in mice lacking lysyl oxidase-like 1 (LOXL1)."
      supports: SUPPORT
      evidence_source: MODEL_ORGANISM
      snippet: "Elimination of LOXL1 in mice impairs the blood-aqueous humor barrier in the ocular anterior segment and causes lens abnormalities consistent with cataract formation, but does not result in deposition of macromolecular material or glaucoma."
      explanation: >-
        The explicit negative result: no deposition of material.
  - target: Elevated Intraocular Pressure
    relationship: FAILS_TO_RECAPITULATE
    fidelity: LOW
    model_scale: ORGANISM
    description: >-
      Pressure stays normal for at least a year, so the model has no glaucoma
      arm.
    limitations: >-
      Without exfoliation material there is nothing to obstruct the meshwork,
      so the absence of raised pressure follows from the absence of the
      upstream lesion rather than telling us anything about the outflow
      biology of the human disease.
    evidence:
    - reference: PMID:24425853
      reference_title: "Disruption of the blood-aqueous barrier and lens abnormalities in mice lacking lysyl oxidase-like 1 (LOXL1)."
      supports: SUPPORT
      evidence_source: MODEL_ORGANISM
      snippet: "Intraocular pressure measurements were within the normal range (16.5 ± 2.0 mm Hg) in null mice up to 1 year of age."
      explanation: >-
        The measured absence of ocular hypertension.
  evidence:
  - reference: PMID:24425853
    reference_title: "Disruption of the blood-aqueous barrier and lens abnormalities in mice lacking lysyl oxidase-like 1 (LOXL1)."
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: "These results show that mice lacking LOXL1 have some ES features but that complete disease manifestation requires other factors that could be genetic and/or environmental."
    explanation: >-
      The authors' own assessment of the model's partial fidelity.
  - reference: PMID:14745449
    reference_title: "Elastic fiber homeostasis requires lysyl oxidase-like 1 protein."
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: "Thus elastin polymer deposition is a crucial aspect of elastic fiber maintenance and is dependent on LOXL1, which serves both as a cross-linking enzyme and an element of the scaffold to ensure spatially defined deposition of elastin."
    explanation: >-
      The dual enzyme-and-scaffold role of LOXL1 that the model established,
      which is the mechanistic content it contributes.
  notes: >-
    Recorded as an informative negative. There is no faithful animal model of
    exfoliation syndrome: no species forms the material spontaneously, and
    LOXL1 loss does not produce it. The HUMAN_MODEL_MISMATCH discussion below
    carries the consequence for the mechanism chain.
diagnosis:
- name: Dilated slit-lamp examination
  description: >-
    Diagnosis is clinical. The deposits on the anterior lens capsule and
    pupillary border are the most consistent and important diagnostic feature,
    and the classic three-zone capsular pattern is seen only through a fully
    dilated pupil, so the examination must be repeated after dilation and
    should note pupil size, iris transillumination, phacodonesis and lens
    position. Tonometry, gonioscopy for angle pigmentation and Sampaolesi line,
    and disc, nerve fibre layer and field assessment stage the glaucoma. There
    is no laboratory, genetic or imaging test for the syndrome; LOXL1
    genotyping has no diagnostic role because the risk alleles are carried by
    most unaffected people.
  evidence:
  - reference: PMID:11166342
    reference_title: "Exfoliation syndrome."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "Deposits of white material on the anterior lens surface are the most consistent and important diagnostic feature of XFS."
    explanation: >-
      The diagnostic sign.
  - reference: PMID:11166342
    reference_title: "Exfoliation syndrome."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "The classic pattern consists of three distinct zones that become visible when the pupil is fully dilated."
    explanation: >-
      Why dilation is required.
differential_diagnoses:
- name: Pigment dispersion syndrome
  description: >-
    The other pigment-associated secondary open-angle glaucoma and the closest
    gonioscopic mimic. Distinguished by age (third to fifth decade, myopic,
    often male), by mid-peripheral radial spoke-like transillumination from
    iridozonular chafing rather than peripupillary loss, by a Krukenberg
    spindle, by dense homogeneous rather than patchy angle pigmentation, and
    by the absence of capsular deposits and zonular weakness.
- name: Primary open-angle glaucoma
  description: >-
    Distinguished by the anterior segment, not the disc: no capsular or
    pupillary-border deposits, no peripupillary transillumination, no poor
    dilation or phacodonesis. Because exfoliation deposits are missed without
    dilation, some glaucoma labelled primary is exfoliation glaucoma, and the
    distinction matters because the course and the surgical risks differ.
- name: True capsular exfoliation
  description: >-
    Lamellar delamination of the anterior lens capsule from chronic infrared
    exposure, classically in glassblowers. A different disease with a
    different mechanism; the shared name is historical and the reason the
    prefix pseudo- was introduced.
  evidence:
  - reference: PMID:38304644
    reference_title: "Cardiovascular Manifestations of Pseudoexfoliation Syndrome: A Narrative Review."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "True exfoliation syndrome is characterized by lamellar delamination of the lens capsule and is caused by exposure to infrared radiation."
    explanation: >-
      Defines the entity this disease must be distinguished from.
- name: Uveitis with pigment or fibrin deposition
  description: >-
    Inflammation can leave pigment and fibrinous debris on the lens and
    endothelium. Distinguished by cells and flare, keratic precipitates,
    synechiae, and the absence of the capsular three-zone pattern and of
    zonular weakness.
prevalence:
- population: Reykjavik, Iceland, adults aged 50 and over
  measure_type: POINT_PREVALENCE
  prevalence_class: ABOVE_1_IN_1000
  rate_per_100000: 10700.0
  notes: >-
    10.7% of a random population sample aged 50 or more had exfoliation in at
    least one eye, rising from 2.5% at 50-59 to 40.6% at 80 and over, with
    women more often affected than men. Iceland is a high-prevalence
    population; prevalence worldwide ranges from below 1% to above 20% by age,
    ancestry, latitude and examination technique.
  evidence:
  - reference: PMID:18028119
    reference_title: "Pseudoexfoliation in the Reykjavik Eye Study: prevalence and related ophthalmological variables."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "In all, 108 (10.7%) persons were found to have PEX in at least one eye."
    explanation: >-
      The population-based prevalence figure recorded.
  - reference: PMID:18028119
    reference_title: "Pseudoexfoliation in the Reykjavik Eye Study: prevalence and related ophthalmological variables."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Prevalence increased from 2.5% in those aged 50-59 years to 40.6% in those aged > or = 80 years."
    explanation: >-
      The age gradient, which is steeper than for almost any other eye
      disease and is why age is the dominant risk factor.
- population: Northern Sweden (Skellefteå), 1915 birth cohort followed from age 66 to 87
  measure_type: POINT_PREVALENCE
  prevalence_class: ABOVE_1_IN_1000
  rate_per_100000: 23000.0
  rate_low: 20000.0
  rate_high: 26000.0
  notes: >-
    23% (95% CI 20-26) at 66 years, rising to 61% at 87 in the same cohort;
    annual incidence 1.8%. The 66-year figure is recorded as the rate; the
    87-year figure shows what a lifetime of exposure does in a Scandinavian
    population.
  evidence:
  - reference: PMID:17986292
    reference_title: "Incidence and prevalence of pseudoexfoliations and open-angle glaucoma in northern Sweden: II. Results after 21 years of follow-up."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The prevalence of PEX increased from 23%[95% confidence interval (CI): 20-26] at 66 years of age to 61% (CI 50-71) at 87 years."
    explanation: >-
      The prospective prevalence figures recorded.
  - reference: PMID:17986292
    reference_title: "Incidence and prevalence of pseudoexfoliations and open-angle glaucoma in northern Sweden: II. Results after 21 years of follow-up."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The annual incidence of PEX was 1.8% (CI 1.3-2.4)."
    explanation: >-
      The incidence in the same cohort, for context.
- population: Worldwide
  measure_type: CASES_IN_LITERATURE
  prevalence_class: COMMON
  notes: >-
    An estimated 60-70 million people affected worldwide, per the 2017
    international genetic study; the report used for this entry cites a
    higher estimate of about 80 million. Prevalence varies widely and no
    single global rate is meaningful, so the qualitative class is used.
  evidence:
  - reference: PMID:28553957
    reference_title: "Genetic association study of exfoliation syndrome identifies a protective rare variant at LOXL1 and five new susceptibility loci."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "This disease is common in many populations, with an estimated 60–70 million patients affected"
    explanation: >-
      The global case estimate; OTHER because it is the paper's background
      synthesis of earlier surveys.
classifications:
  harrisons_chapter:
  - classification_value: NEUROLOGIC
    notes: >-
      Assigned to match the sibling Glaucoma entry, which places glaucomatous
      optic neuropathy with the neurologic disorders; the eye chapter of
      Harrison's sits in the cardinal-manifestations Part, which the
      classification skill reserves for symptom-defined entries.
discussions:
- discussion_id: xfs_loxl1_allele_reversal_and_initiating_lesion
  prompt: >-
    What is the functional LOXL1 lesion, given that the coding risk alleles
    reverse direction between ancestries, and what initiates fibrillogenesis
    in a person who carries it?
  kind: KNOWLEDGE_GAP
  status: OPEN
  attaches_to:
  - pathophysiology#LOXL1 Susceptibility Genotype
  - pathophysiology#Dysregulated LOXL1 Expression and Elastic Microfibril Cross-Linking
  rationale: >-
    The LOXL1 association is among the strongest in complex disease and
    among the least understood. The coding variants cannot be causal in a
    simple sense because the risk allele at rs3825942 is protective in black
    South Africans and the rs1048661 risk allele is protective in East Asians;
    the regulatory variant rs11638944 lowers LOXL1 mRNA in carriers, yet ocular
    LOXL1 is increased in early disease; and Loxl1-null mice form no material.
    Whether the disease is a proteopathy of a misfolding-prone LOXL1
    N-terminus, a stage-dependent dysregulation of an otherwise normal enzyme,
    or a stress-response defect mediated through LOXL1-AS1, the three current
    models make different predictions about which patients will progress and
    what a disease-modifying therapy should do, and none has been tested in
    vivo. The patient-derived fibroblast work that supports the proteopathy
    model uses trabeculectomy specimens from advanced glaucoma, so it may be
    reporting late consequences rather than initiation.
  proposed_experiments:
  - experiment_id: xfs_ancestry_stratified_loxl1_fine_mapping
    name: Ancestry-stratified fine mapping and allele-specific expression at LOXL1
    description: >-
      Fine-map the LOXL1 locus in the ancestries where the coding alleles
      reverse, using allele-specific expression in anterior-segment tissue
      from cataract surgery, to identify a regulatory haplotype whose
      direction of effect is consistent across populations. A variant that
      behaves the same way in South African and Icelandic eyes would be the
      functional lesion; the coding SNPs have already failed that test.
- discussion_id: xfs_no_faithful_animal_model
  prompt: >-
    Can the Loxl1-null mouse, which loses elastic fibres but forms no
    exfoliation material and develops no glaucoma, inform the ocular mechanism
    of the human disease at all?
  kind: HUMAN_MODEL_MISMATCH
  status: OPEN
  attaches_to:
  - pathophysiology#Exfoliation Material Fibrillogenesis and Deposition
  - animal_models#Loxl1-null mouse
  rationale: >-
    The mismatch is mechanistically meaningful in both directions. The mouse
    shows that LOXL1 loss alone does not make exfoliation material, which
    supports the human genetics in saying that LOXL1 sets susceptibility rather
    than causing disease; but it also means every human mechanism between
    genotype and deposit (the TGF-beta1 milieu, chaperone deficiency,
    aggregation of microfibrillar components) rests on human tissue and
    cultured cells with no in vivo test. The model reproduces the systemic
    elastic-tissue arm faithfully enough that pelvic organ prolapse in
    Loxl1-null mice is the best mechanistic support the human prolapse
    association has, so the same model is informative for one half of the
    disease and silent on the other. There is no naturally occurring
    veterinary counterpart.
  proposed_experiments:
  - experiment_id: xfs_humanized_loxl1_stress_model
    name: Aged mouse carrying human LOXL1 risk haplotype under chronic ultraviolet and oxidative stress
    description: >-
      Replace mouse Loxl1 regulatory sequence with the human risk haplotype
      including rs11638944 and the LOXL1-AS1 promoter region, age the animals,
      and apply chronic ultraviolet and oxidative stress to the anterior
      segment, scoring lens capsule and ciliary epithelium for fibrillar
      deposits by electron microscopy and LOXL1 immunolabelling. The human
      disease requires genotype, age and stress together; no existing model
      combines them.
- discussion_id: xfs_systemic_associations_causal_or_confounded
  prompt: >-
    Are the cardiovascular, cerebrovascular, hearing and pelvic-floor
    associations consequences of systemic elastosis, or confounding in an
    elderly, ultraviolet-exposed population?
  kind: KNOWLEDGE_GAP
  status: OPEN
  attaches_to:
  - pathophysiology#Systemic Elastosis
  - phenotypes#Abnormality of the cardiovascular system
  - phenotypes#Sensorineural hearing impairment
  - phenotypes#Pelvic organ prolapse
  rationale: >-
    Deposits in vessel walls, heart and skin are real, and the meta-analytic
    association with vascular disease survives sensitivity analysis. But the
    studies are observational in people in their seventies, the cerebrovascular
    signal shows publication bias, the hearing series is a single uncontrolled
    clinic sample, and the prolapse association comes from diagnosis codes in
    a population database. No study has shown that the deposits impair
    vascular or cochlear function, and the earlier review of this disease was
    careful to call the associations preliminary. The distinction matters
    because a causal systemic disease would justify screening that an
    association does not.
  proposed_experiments:
  - experiment_id: xfs_mendelian_randomization_systemic
    name: Mendelian randomisation of systemic outcomes on exfoliation genotype
    description: >-
      Use the LOXL1 and other exfoliation risk alleles as instruments for
      cardiovascular, cerebrovascular, hearing and pelvic-floor outcomes in
      biobank data, within ancestry to respect the allele reversal. A genetic
      instrument is not confounded by age or sun exposure; an effect would
      make the systemic arm causal, and a null would argue for confounding.
- discussion_id: xfs_lamina_cribrosa_and_pressure_vulnerability
  prompt: >-
    Does lamina cribrosa elastosis make the exfoliation optic nerve more
    vulnerable to a given pressure, explaining the doubled conversion rate at
    matched pressure and the faster field loss?
  kind: KNOWLEDGE_GAP
  status: OPEN
  attaches_to:
  - pathophysiology#Lamina Cribrosa Elastosis
  - pathophysiology#Exfoliation Glaucoma Optic Neuropathy
  rationale: >-
    Ocular hypertensives with the syndrome convert to glaucoma at twice the
    rate of controls matched for pressure, age and sex, so pressure alone does
    not explain the worse course. Site-specific elastosis of the lamina
    cribrosa, greater than in primary open-angle glaucoma, is the obvious
    structural candidate, but the histology comes from four optic nerve heads
    of two patients and no study has related laminar elastin content or
    biomechanics to progression. The alternative explanation, that undetected
    pressure fluctuation accounts for the excess risk, has not been excluded
    either.
  proposed_experiments:
  - experiment_id: xfs_laminar_biomechanics_oct
    name: In vivo lamina cribrosa biomechanics against progression rate
    description: >-
      Measure laminar depth, curvature and deformation under acute pressure
      change with optical coherence tomography in exfoliation glaucoma and
      pressure-matched primary open-angle glaucoma, and relate the measures to
      field progression over follow-up. A more deformable lamina at matched
      pressure in the exfoliation eyes would support the elastosis
      hypothesis; equal biomechanics would point back to pressure fluctuation.

📚

References & Deep Research

References

3

PMID:11166342

Exfoliation syndrome.

No top-level findings curated for this source.

PMID:16678509

Ocular and systemic pseudoexfoliation syndrome.

No top-level findings curated for this source.

PMID:28553957

Genetic association study of exfoliation syndrome identifies a protective rare variant at LOXL1 and five new susceptibility loci.

No top-level findings curated for this source.

Deep Research

1

Deep research results are used as seeds for research; they do not undergo the same validation as the main records and may contain errors. How we use deep research.

Evaluations and curation notes (2)

Record notes

Disease term. The entry is keyed on MONDO:0100046 ("exfoliation syndrome, susceptibility to") because that is the MONDO identifier the curation stub and claim issue were filed under; it is the OMIM 177650 (XFS1) concept and carries no synonyms of its own. It is not, however, MONDO's only concept for this disease: MONDO:0008327 "exfoliation syndrome" is a live term with the synonyms XFS, XFG and pseudoexfoliation glaucoma and the Orphanet, DOID, MeSH and NCIT cross-references, and it is the term a reader would expect. It is mapped as an exact match under `mappings` so that coverage tooling retires both concepts. Repointing `disease_term` to MONDO:0008327 is a reasonable follow-up and is flagged in the curation history rather than done silently here. The two terms are not duplicates, which is worth stating because they look like one. MONDO:0100046 is an `inherited disease susceptibility` class that MONDO relates to MONDO:0008327 with `predisposes_towards`; so MONDO carries both a disease concept and a susceptibility concept for this entity, and the `skos:exactMatch` recorded above is a claim about what this file curates - the disease in full - rather than a claim that the two MONDO classes are the same thing. Gene relation: this entry disagrees with MONDO. MONDO relates both terms to LOXL1 with RO:0004003, "has material basis in germline mutation in", and the NCIT-derived definition of MONDO:0008327 calls the condition "An autosomal dominant disorder caused by mutations in the LOXL1 gene". The genetics recorded in the LOXL1 entry below do not support reading it that way: the risk allele reverses between ancestries, the coding variants are carried by most unaffected people, and the knockout mouse does not form exfoliation material. This entry therefore binds LOXL1 as SUSCEPTIBILITY and leaves the disagreement visible rather than adopting MONDO's relation. The same reading is implicit in MONDO's own structure, which needed a separate "susceptibility to" class to express the relationship at all. Scope. Exfoliation syndrome and exfoliation glaucoma are curated as one entry, as one spectrum, for the reason given in Pigment_Dispersion_Syndrome: the chain from deposited material to raised pressure to optic neuropathy is continuous, and only the last node changes the diagnosis. The boundary is explicit at the node level: everything up to and including elevated intraocular pressure is the syndrome, and exfoliation glaucoma requires glaucomatous optic neuropathy in addition. True capsular exfoliation (the infrared, glassblower's delamination of the lens capsule) is a different disease and is listed only as a differential. Module conformance. The outflow and optic-neuropathy arm conforms to `glaucoma_optic_neuropathy` at four nodes (Trabecular Meshwork Outflow Dysfunction, Elevated Intraocular Pressure, Retinal Ganglion Cell Apoptosis, Progressive Glaucomatous Optic Neuropathy). The disorder-specific substitution is the cause of the trabecular dysfunction: physical obstruction of the meshwork by exfoliation material and liberated iris pigment, rather than the primary juxtacanalicular pathology of open-angle glaucoma. The entry adds one node the module does not have, elastosis of the lamina cribrosa, because it is specific to this disease and is the leading explanation for why these optic nerves fare worse at a given pressure. Genetics. LOXL1 is typed SUSCEPTIBILITY, not CAUSATIVE, and inheritance is recorded as polygenic. The reasons are in the genetic block: population attributable risk above 99% together with risk-allele carriage in most unaffected people, reversal of the rs3825942 risk allele in black South Africans and of rs1048661 in Japanese and Koreans, and strong age dependence. No GeneReviews chapter exists for this disease (PubMed searched for "exfoliation syndrome GeneReviews" and "pseudoexfoliation GeneReviews" on 2026-09-18; none found), which is expected for a complex trait; there is therefore no GeneReviews-tagged reference. Systemic associations. Exfoliation material has been demonstrated in visceral organs and skin, so the systemic elastosis node is a histological fact. The clinical associations that travel with it (cardiovascular and cerebrovascular events, sensorineural hearing loss, pelvic organ prolapse) are recorded as phenotypes with the association-level evidence that exists, with the caveats in their descriptions, and the question of whether they are consequences or confounders is a knowledge gap rather than a mechanism. Provenance. Built from an Edison Falcon deep-research report (research/Exfoliation_Syndrome-deep-research-falcon.md; 17/17 references resolved, 2/2 terms resolved, preflight PASS on MONDO:0100046 with LOXL1 as the expected gene). Falcon cites by DOI and corpus key, so every DOI used was resolved to its PubMed record through the PMC ID converter and all evidence here is cited and verified against PMIDs. The report proposed MONDO:0008327 as the disease term, which is the discrepancy discussed above. Primary mechanism, histopathology, epidemiology and animal-model papers were located by PubMed E-utilities searches beyond the report's citation list.

Create: Exfoliation Syndrome (MONDO:0100046) · 2026-09-18T14:28:15Z · View source

New entry curated from the Edison Falcon deep-research report research/Exfoliation_Syndrome-deep-research-falcon.md, with Falcon DOIs resolved to PMIDs through PubMed before use and every snippet quoted from the cached abstract. Thirteen-node pathograph: LOXL1 susceptibility genotype, TGF-beta1 excess and oxidative stress in the anterior segment, dysregulated LOXL1 expression and elastic microfibril cross-linking, extracellular chaperone deficiency, exfoliation material fibrillogenesis and deposition, then the three tissue consequences (zonular degradation, iris pigment epithelial degeneration with pigment dispersion, trabecular obstruction by material and pigment) converging on elevated intraocular pressure, lamina cribrosa elastosis, retinal ganglion cell apoptosis and exfoliation glaucoma optic neuropathy, with systemic elastosis as a parallel branch. The glaucoma arm conforms to glaucoma_optic_neuropathy at four nodes; the disorder-specific substitution is physical obstruction of the meshwork by exfoliation material and liberated pigment. Syndrome and glaucoma are curated as one entry with the diagnostic boundary explicit at the node level, following Pigment_Dispersion_Syndrome. Disease term kept on MONDO:0100046 because that is the stub and claim key; MONDO:0008327 (exfoliation syndrome, the term a reader expects) is mapped as an exact match and repointing disease_term to it is flagged as a follow-up. LOXL1 recorded as SUSCEPTIBILITY with polygenic inheritance and the population risk-allele reversal noted; no Mendelian gene asserted. No GeneReviews chapter exists. The Loxl1-null mouse is recorded honestly as failing to form exfoliation material. Systemic cardiovascular and other associations are recorded with their evidence rather than as established mechanism. Validated: just validate passed; count-verified-snippets 128/128; validate-terms, check-entity-refs, check-causal-targets, check-enum-values and check-duplicate-keys passed; pytest -k Exfoliation_Syndrome passed. A first attempt at this curation was cut off by a session limit before writing; this record describes the completed second pass.

Falcon ▸

Exfoliation Syndrome: Disease Characteristics Research Report

Edison Scientific Literature 52 citations 2026-09-04T23:35:54.267271

Exfoliation Syndrome: Disease Characteristics Research Report

Scope. This report distinguishes exfoliation syndrome (XFS)—the matrix-deposition disorder—from exfoliation glaucoma (XFG), its major sight-threatening complication. Evidence labels used below are human clinical, human observational, human molecular, in vitro, animal model, or computational. Associations are not described as causal unless experimentally established.

The following table provides a knowledge-base-oriented synopsis.

Knowledge-base domain	Evidence-based summary	Key quantitative values	Suggested ontology annotations	Evidence
Identity and definition	Exfoliation syndrome (XFS; pseudoexfoliation syndrome, PXS/PEX) is a late-onset, systemic extracellular-matrix disorder characterized by progressive production and deposition of abnormal fibrillar exfoliation material, with clinically dominant manifestations in the ocular anterior segment. Exfoliation glaucoma (XFG/PXG) is the secondary open-angle glaucoma that may complicate XFS; it is not synonymous with uncomplicated XFS.	Estimated prevalence varies geographically from <0.4% to >20%; approximately 80 million people may be affected worldwide.	MONDO:0008327 exfoliation syndrome; MeSH concept: pseudoexfoliation syndrome; HPO: HP:0003584 late onset	(li2021loxl1genepolymorphisms pages 1-2, bernstein2018exfoliationsyndromea pages 1-4, elhawy2012pseudoexfoliationsyndromea pages 1-2, OpenTargets Search: pseudoexfoliation syndrome,exfoliation glaucoma-LOXL1)
Genetics	XFS is a complex, polygenic susceptibility disorder—not a proven Mendelian LOXL1 disease. Common coding and regulatory variants in LOXL1 are the strongest replicated associations, but risk-allele reversal and high risk-allele frequencies across ancestries preclude classification as individually pathogenic variants. Additional GWAS loci include CACNA1A, POMP, TMEM136, AGPAT1, RBMS3, and SEMA6A. A rare LOXL1 coding variant was reported as protective.	2017 GWAS: 9,035 cases and 17,008 controls across 25 strata; initial LOXL1 SNP ORs reported in the range 2.46–20.10. A 2021 meta-analysis included 5,022 cases and 8,962 controls.	HGNC genes: LOXL1, CACNA1A, POMP, TMEM136, AGPAT1, RBMS3, SEMA6A; GO: extracellular-matrix organization, elastic-fiber assembly	(li2021loxl1genepolymorphisms pages 1-2, aung2017geneticassociationstudy pages 24-38, aboobakar2022thegeneticsof pages 6-8, OpenTargets Search: pseudoexfoliation syndrome,exfoliation glaucoma-LOXL1)
Environment and gene–environment interaction	Age is the dominant non-genetic risk factor. Latitude, cold climate, greater summer outdoor exposure, reflected light over snow or water, UV-related skin-cancer history, heavy coffee intake, and low folate have observational associations. UV can induce LOXL1 and matrix responses experimentally, supporting—but not proving—a LOXL1–UV interaction. Sunglasses are a plausible protective exposure, but no intervention trial demonstrates prevention.	Each degree farther from the equator: OR 1.11 (95% CI 1.05–1.17); each additional summer outdoor hour/week: OR 1.04 (1.00–1.07); US work over snow/water: OR 3.86 (1.36–10.9); each 1% increase in sunglasses use: OR 0.98 (0.97–0.99), not replicated in Israel.	Exposure concepts: ultraviolet radiation, cold temperature, outdoor occupational exposure; CHEBI candidates for research annotation: folate, homocysteine, caffeine	(pasquale2014considerationforgeneenvironment pages 4-6, pasquale2014solarexposureand pages 1-2, pasquale2014considerationforgeneenvironment pages 2-4, kang2020cohortstudyof pages 6-7)
Core ocular phenotypes	Characteristic manifestations are white-gray fibrillar deposits on the anterior lens capsule and pupillary margin, iris depigmentation and peripupillary transillumination, poor pharmacologic mydriasis, trabecular hyperpigmentation, elevated or fluctuating intraocular pressure, zonular weakness, phacodonesis, lens subluxation/dislocation, cataract, and reduced corneal endothelial-cell density. Disease may appear unilateral but is often biologically asymmetric and ultimately bilateral.	Approximately 44% has been estimated to progress to XFG, although estimates vary by cohort.	HPO suggestions: glaucoma, increased intraocular pressure, visual-field defect, cataract, lens subluxation, poor pupillary dilation, iris transillumination defect; UBERON: anterior lens capsule, iris, ciliary body, trabecular meshwork, zonular fibers, corneal endothelium	(li2021loxl1genepolymorphisms pages 1-2, rong2024lackofassociation pages 8-9, elhawy2012pseudoexfoliationsyndromea pages 1-2, borjan2023pseudoexfoliativesyndromein pages 2-3)
Mechanism	Genetic susceptibility and aging, potentially amplified by UV, oxidative stress, and low-grade inflammation, alter TGF-β–LOXL1 signaling and elastic-fiber/ECM homeostasis. Increased or dysregulated matrix synthesis, LOXL1 misfolding, impaired proteasome–autophagy–lysosome clearance, mitochondrial dysfunction, and reduced antioxidant defense promote extracellular fibril accumulation. Deposits and liberated iris pigment obstruct trabecular outflow, raising intraocular pressure; sustained pressure and vascular/oxidative stress then cause retinal-ganglion-cell and optic-nerve injury. Several upstream links remain inferred rather than proven.	Early XFS aqueous-humor IL-6 and IL-8 were about threefold higher than controls. Lens-capsule RNA-seq identified 2,882 differentially expressed genes in 25 XFS vs 39 controls.	GO: extracellular-matrix organization, elastic-fiber assembly, response to oxidative stress, autophagy, lysosomal transport, mitochondrial respiratory-chain activity, TGF-β signaling; CL: lens epithelial cell, non-pigmented ciliary epithelial cell, iris pigment epithelial cell, trabecular-meshwork cell, fibroblast, retinal ganglion cell	(shyam2023geneticandepigenetic pages 43-47, bernstein2018exfoliationsyndromea pages 1-4, borras2018growthfactorsoxidative pages 8-10, mullany2022rnasequencingof pages 1-2)
Diagnosis	Diagnosis is clinical by slit-lamp examination before and after dilation, looking for exfoliation material, the classic lens-capsule pattern, pupillary-border deposits, poor dilation, transillumination defects, and zonular instability. Tonometry, gonioscopy, optic-disc examination, OCT retinal-nerve-fiber/ganglion-cell analysis, and automated perimetry stage ocular hypertension or XFG. There is no validated blood, genetic, omics, biopsy, imaging, or molecular test for routine diagnosis.	No standardized molecular diagnostic threshold or clinically validated predictive genetic test is available.	SNOMED/LOINC domains: slit-lamp examination, intraocular pressure, gonioscopy, automated visual-field testing, optic-nerve OCT	(rong2024lackofassociation pages 8-9, elhawy2012pseudoexfoliationsyndromea pages 1-2, aboobakar2022thegeneticsof pages 6-8, OpenTargets Search: pseudoexfoliation syndrome,exfoliation glaucoma-LOXL1)
Prognosis and burden	XFS itself does not have an established disease-specific mortality effect, but it confers substantial ocular morbidity through XFG, cataract, zonular failure, and surgical complications. XFG generally has higher pressure, greater fluctuation, poorer medical response, and faster visual-field deterioration than primary open-angle glaucoma.	Three-year study: mean-deviation change −3.17 dB in XFG vs −1.25 dB in POAG; progression by guided progression analysis 58% vs 13%. Indian tertiary cohort: XFG in 29% of 6,284 XFS eyes and overall absolute blindness 28.2% at presentation.	HPO: progressive visual-field loss, optic atrophy/glaucomatous optic neuropathy, visual impairment, blindness	(li2021loxl1genepolymorphisms pages 1-2, aboobakar2022thegeneticsof pages 6-8)
Treatment and implementation	No therapy removes exfoliation material or modifies the underlying systemic matrix disease. Uncomplicated XFS requires surveillance. XFG is treated by lowering intraocular pressure with standard topical agents, selective laser trabeculoplasty (SLT), lens extraction when indicated, trabeculectomy, drainage implants, or selected minimally invasive procedures. Cataract surgery requires anticipation of poor dilation and zonular weakness, with iris-expansion devices, capsular hooks, or capsular-tension rings as needed.	2024 SLT series: IOP 26.7→18.9 mmHg at 3 months, 29.2% reduction, 69.4% success. PreserFlo series: IOP 32.6→16.9 mmHg, medications 3.4→1.0, but 31% reoperation and 17% hypotony. Croatian registry: PEX cataract surgery cost 1.4-fold higher.	NCIT suggestions: ophthalmic solution, selective laser trabeculoplasty, phacoemulsification, trabeculectomy, glaucoma drainage implant, minimally invasive glaucoma surgery, capsular-tension ring placement	(wakuda2024postoperativeoutcomesof pages 4-6, borjan2023pseudoexfoliativesyndromein pages 2-3, borjan2023pseudoexfoliativesyndromein pages 12-14, NCT04635020 chunk 1, NCT04416724 chunk 1)
Research and evidence gaps	Major gaps include the initiating lesion, functional interpretation of ancestry-dependent LOXL1 alleles, validated gene–environment interactions, reliable conversion biomarkers, single-cell and spatial atlases, faithful animal models, and disease-modifying therapy. Existing omics studies are generally small and require independent, multi-ancestry replication. Active implementation research includes phacoemulsification versus SLT and cataract surgery plus iStent versus SLT; completed XEN45 real-world evidence enrolled 350 participants, but the registry excerpt did not provide numerical outcomes.	Prediagnostic metabolomics: 205 incident XFG cases and 205 controls, mean 11.8 years before diagnosis; cortisone OR 0.49 per SD (95% CI 0.32–0.74). CANPEX1: planned n=200; iStent-versus-laser trial: planned n=285; XEN45 observational study: n=350.	Study annotations: bulk RNA sequencing, metabolomics, prospective cohort study, randomized controlled trial, model-organism limitation	(bernstein2018exfoliationsyndromea pages 1-4, kang2022prediagnosticplasmametabolomics pages 1-2, mullany2022rnasequencingof pages 1-2, NCT06993311 chunk 1, NCT04416724 chunk 1, NCT04635020 chunk 1)

Table: Compact evidence-based summary of exfoliation syndrome identity, risk architecture, phenotypes, mechanism, diagnosis, prognosis, management, and research gaps. Quantitative findings and suggested knowledge-base ontology annotations are included.

1. Disease information

Definition

Exfoliation syndrome is a chronic, strongly age-dependent, complex disorder of extracellular-matrix (ECM) production and clearance. Abnormal fibrillar exfoliation material (XFM) accumulates most visibly in the ocular anterior segment—especially on the anterior lens capsule, pupillary margin, iris, ciliary body, zonules, and trabecular meshwork. Similar material has been reported histologically in visceral tissues, supporting the concept of a systemic matrix disorder, although its clinically established morbidity is predominantly ocular. A useful abstract-level definition is: “Pseudoexfoliation syndrome (PXS) is a systemic condition with eye manifestations.” (Human pathology/review.) (elhawy2012pseudoexfoliationsyndromea pages 1-2)

XFS is not synonymous with XFG. XFG is secondary, usually open-angle glaucoma caused when XFM and liberated iris pigment increase aqueous-outflow resistance and intraocular pressure (IOP), followed by glaucomatous retinal-ganglion-cell and optic-nerve injury. Estimates suggest that approximately 44% of affected people may develop XFG, but conversion varies by population, ascertainment, and follow-up. XFG accounts for approximately 25% of open-angle glaucoma worldwide in some estimates. (li2021loxl1genepolymorphisms pages 1-2, bernstein2018exfoliationsyndromea pages 1-4)

Identifiers and synonyms

Preferred name: exfoliation syndrome.
MONDO: MONDO:0008327.
OMIM: commonly represented as Exfoliation syndrome 1 / XFS1, #177650; database release should be checked before production ingestion.
MeSH: Exfoliation Syndrome / Pseudoexfoliation Syndrome.
Common synonyms: pseudoexfoliation syndrome, pseudo-exfoliation syndrome, PXS, PEX, PEXS, XFS, exfoliative syndrome, capsular glaucoma with pseudoexfoliation when glaucoma is present.
Related but distinct: exfoliation glaucoma/pseudoexfoliation glaucoma (XFG/PXG/PEG); true capsular exfoliation, an occupational/infrared-associated delamination of the lens capsule, is not XFS.
ICD: coding is jurisdiction/version dependent. XFS without glaucoma is generally placed under “other specified cataract/anterior-segment” categories, whereas capsular/exfoliation glaucoma is coded within secondary glaucoma categories. Exact ICD-10-CM/ICD-11 codes should be validated against the target terminology release rather than inferred from literature.

The evidence summarized here is aggregated disease-level evidence from cohorts, case-control studies, tissue studies, registries, GWAS, and reviews—not individual EHR-derived patient data.

2. Etiology and risk architecture

Causal and susceptibility factors

XFS is multifactorial and polygenic. No single variant is necessary or sufficient. Aging is the dominant background determinant; genetic susceptibility, environmental exposure, ECM dysregulation, oxidative stress, inflammation, and impaired proteostasis converge over decades.

LOXL1 is the strongest replicated susceptibility gene. It encodes lysyl oxidase-like 1, an enzyme involved in collagen/elastin cross-linking and elastic-fiber homeostasis. Common variants rs1048661, rs3825942, and rs2165241 are repeatedly associated with XFS/XFG, but their effects differ by ancestry and risk alleles can reverse direction between populations. A 2021 meta-analysis included 5,022 cases and 8,962 controls and found ancestry-dependent associations; this establishes susceptibility, not monogenic causality. Li et al., published 28 April 2021, DOI. (li2021loxl1genepolymorphisms pages 1-2)

A major 2017 GWAS meta-analysis included 9,035 cases and 17,008 controls across 25 strata, identifying a rare protective LOXL1 coding variant and susceptibility loci near/in POMP, TMEM136, AGPAT1, RBMS3, and SEMA6A, in addition to LOXL1 and CACNA1A. The protective variant is conventionally reported as LOXL1 p.Tyr407Phe (p.Y407F). Aung et al., May 2017, Nature Genetics, DOI. (aung2017geneticassociationstudy pages 24-38) Open Targets independently maps LOXL1 (ENSG00000129038) to MONDO:0008327 and links supporting literature including PMIDs 17690259, 18037624, 18385788, 19343041, 24938310, and 36653562. (OpenTargets Search: pseudoexfoliation syndrome,exfoliation glaucoma-LOXL1)

These are common/rare germline susceptibility alleles, not somatic cancer-like mutations. They should not ordinarily be labeled “pathogenic” under ACMG/AMP Mendelian criteria. Population frequencies are too high, penetrance is incomplete and age dependent, and no validated carrier-frequency concept applies. There is no established role for aneuploidy, translocation, repeat expansion, mitochondrial mutation, germline mosaicism, anticipation, or consanguinity.

Environmental and lifestyle factors

Human observational evidence implicates lifetime latitude, cold climate, greater summer outdoor exposure, and reflected light. In a US/Israeli case-control study of adults aged ≥60 years, each degree farther from the equator was associated with 11% higher odds of XFS (OR 1.11, 95% CI 1.05–1.17); each additional average summer outdoor hour/week had OR 1.04 (1.00–1.07). US work over snow or water had OR 3.86 (1.36–10.9). Greater sunglasses use was inversely associated in the US (OR 0.98 per 1% increment) but not Israel. Pasquale et al., December 2014, DOI. These findings are vulnerable to recall, selection, and residual confounding and do not prove that UV causes XFS or sunglasses prevent it. (pasquale2014solarexposureand pages 1-2)

Other reported associations include heavy coffee/caffeine intake, low folate, higher homocysteine, outdoor occupations, more sunny days, and lower ambient temperature. Evidence for smoking, alcohol, diabetes, and cardiovascular factors is inconsistent and does not support causal classification. UV can upregulate lysyl-oxidase/ECM responses in experimental eye and skin systems, offering a plausible gene–environment mechanism, but replicated genotype-by-exposure interaction estimates remain lacking. (pasquale2014considerationforgeneenvironment pages 4-6, pasquale2014considerationforgeneenvironment pages 2-4, kang2020cohortstudyof pages 6-7)

Protective factors: LOXL1 p.Y407F is the clearest genetic protective association. Sunglasses/ocular UV protection and folate sufficiency are biologically plausible environmental protective factors, but neither has preventive-trial confirmation. No drug, dietary supplement, or behavior is proven to prevent XFS.

3. Phenotypes

XFS is generally late-onset, insidious, chronic, progressive, and variably asymmetric. It is uncommon before 50–60 years and becomes increasingly prevalent with age. A clinically unilateral presentation frequently represents asymmetric bilateral disease.

Phenotype	Type and characteristics	Suggested HPO mapping
White-gray fibrillar deposits on anterior lens/pupillary border	Cardinal slit-lamp sign; progressive	Abnormality of lens/anterior eye morphology; local term may be required
Poor pharmacologic mydriasis	Clinical sign caused by iris stromal/sphincter changes; common and surgically important	Abnormal pupillary response / miosis
Peripupillary iris transillumination and pigment loss	Clinical sign; variable	Iris transillumination defect
Trabecular hyperpigmentation/Sampaolesi line	Gonioscopic sign	Abnormal anterior-chamber-angle morphology
Elevated/fluctuating IOP	Laboratory/functional measurement; absent in uncomplicated XFS, prominent in XFG	Increased intraocular pressure
Secondary open-angle glaucoma	Progressive optic neuropathy with field loss	Glaucoma; visual-field defect; optic atrophy
Zonular weakness, phacodonesis, lens subluxation/dislocation	Progressive structural phenotype; increases cataract-surgery risk	Phacodonesis; ectopia lentis/lens subluxation
Cataract	Age-associated comorbidity and major reversible cause of visual loss	Cataract
Reduced corneal endothelial density	Quantitative ocular sign reported in recent clinical studies	Corneal endothelial abnormality
Visual impairment/blindness	Downstream disability from cataract or XFG	Visual impairment; blindness

The characteristic lens pattern and associated iris, zonular, and trabecular findings are well documented. Zonular loss can cause vitreous loss, lens or intraocular-lens complex dislocation, and difficult cataract surgery. (elhawy2012pseudoexfoliationsyndromea pages 1-2, borjan2023pseudoexfoliativesyndromein pages 2-3)

Quality of life declines primarily through visual-field loss, impaired acuity, medication burden, treatment adverse effects, surgery, and loss of independence. Disease-specific EQ-5D or PROMIS norms were not identified. In an Indian tertiary-care cohort of 6,284 XFS eyes, XFG was present in 29%; the study reported substantial visual impairment and 28.2% absolute blindness at presentation, illustrating referral-setting burden rather than population risk.

4. Genetic, molecular, and epigenetic information

LOXL1 is a susceptibility gene, not a fully penetrant causal gene. Common coding variants include p.Arg141Leu (rs1048661) and p.Gly153Asp (rs3825942); rs2165241 is intronic. Functional studies support effects on LOXL1 expression, processing, stability, or aggregation, but population-dependent allele reversal means simple loss-of-function/gain-of-function labels are inadequate. A cited functional study is Sharma et al., 2016, PMID 26997634. (li2021loxl1genepolymorphisms pages 21-21)

Additional loci implicate calcium signaling (CACNA1A), proteasome maturation (POMP), membrane biology (TMEM136), phospholipid metabolism (AGPAT1), RNA binding/ECM regulation (RBMS3), and semaphorin signaling (SEMA6A). Earlier candidate-gene signals involving CNTNAP2, CLU, MMP1/MMP3, GST genes, adenosine receptors, and LYST are less definitive than GWAS evidence. (elhawy2012pseudoexfoliationsyndromea pages 1-2, aboobakar2022thegeneticsof pages 6-8)

Epigenetic regulation of LOXL1 and ECM/stress-response genes is an active hypothesis. DNA methylation, histone regulation, microRNAs, and environmentally responsive transcription may explain part of age and exposure dependence, but no epigenetic biomarker is clinically validated. No reproducible large chromosomal abnormality is established.

5. Environmental information

Relevant exposure categories are solar/ocular UV and reflected light, cold/latitude-associated climate, outdoor occupation, caffeine/coffee, and nutritional factors affecting folate–homocysteine metabolism. Non-melanoma skin cancer, used as a proxy for cumulative UV exposure, was associated with 40% higher XFG risk in 120,307 US participants followed for >25 years (445 incident cases; adjusted RR 1.40, 95% CI 1.08–1.82), with stronger associations below age 65 and at northern latitudes. Kang et al., March 2020, DOI. This remains proxy-based observational evidence. (kang2020cohortstudyof pages 2-3, kang2020cohortstudyof pages 6-7)

No infectious bacterium, virus, fungus, or parasite has been established as a cause. Upregulation of “viral gene-expression pathways” in lens RNA-seq refers to host pathway annotation and must not be interpreted as evidence of infection. (mullany2022rnasequencingof pages 1-2)

6. Mechanism and pathophysiology

Ordered causal chain

Advanced age plus polygenic susceptibility—especially LOXL1 regulatory/coding architecture—leads to vulnerable elastic-fiber and ECM homeostasis in anterior-segment tissues.
Environmental stressors, plausibly ocular UV/cold-reflection exposure, lead to oxidative stress and stress-responsive LOXL1/TGF-β expression; this interaction is biologically supported but partly inferred.
TGF-β dysregulation, inflammation, and redox imbalance lead to increased production and altered assembly of fibrillin-, elastin-, basement-membrane-, and LOXL1-containing matrix components.
LOXL1 misfolding plus proteasome, autophagosome, lysosome, microtubule, and mitochondrial dysfunction leads to defective intracellular quality control and extracellular accumulation of aggregated XFM; causality is strongest in patient-derived cellular work but remains incompletely demonstrated in vivo.
XFM deposition on iris, lens, ciliary epithelium, zonules, and trabecular meshwork leads to two branches:
zonular/iris injury leads to poor dilation, pigment liberation, phacodonesis, lens instability, and cataract-surgical complications;
trabecular XFM and pigment loading leads to increased aqueous-outflow resistance and elevated/fluctuating IOP.
Sustained IOP and associated vascular/oxidative stress lead to retinal-ganglion-cell axonal injury, optic-nerve cupping, progressive visual-field loss, and potentially irreversible blindness.

TGF-β1/2, LOXL1, fibrillin-1, LTBP1, clusterin, ApoE, and matrix metalloproteinase/tissue-inhibitor balance are central molecular candidates. Early XFS aqueous humor reportedly contains approximately threefold higher IL-6 and IL-8; IL-6 induces several XFM-associated ECM transcripts in cultured ciliary epithelial cells and Tenon fibroblasts. (shyam2023geneticandepigenetic pages 43-47, borras2018growthfactorsoxidative pages 8-10)

Patient-derived XFG Tenon fibroblasts exhibit defective lysosomal positioning, microtubule organization, autophagic processing, and mitochondrial health. The authors’ central model is LOXL1 proteopathy superimposed on impaired autophagic clearance. Bernstein et al., July 2018, DOI. (bernstein2018exfoliationsyndromea pages 1-4)

Molecular profiling

Bulk RNA-seq: Lens capsular epithelium from 25 XFS and 39 controls identified 2,882 differentially expressed genes. The abstract reports: “Genes associated with viral gene expression pathways were among the most upregulated, alongside genes encoding ribosomal and mitochondrial respiratory transport chain proteins.” Cell-adhesion/type-IV-collagen transcripts were downregulated. Mullany et al., 29 March 2022, DOI. (mullany2022rnasequencingof pages 1-2)
Prediagnostic metabolomics: In 205 incident XFG cases and 205 matched controls, plasma collected a mean 11.8 years before diagnosis showed FDR-significant associations for lysophosphatidylcholines, phosphatidylethanolamine plasmalogens, triglycerides, and steroids. Cortisone had OR 0.49 per SD (95% CI 0.32–0.74). This is biomarker discovery, not clinical validation or proof of protection. Kang et al., 11 August 2022, DOI. (kang2022prediagnosticplasmametabolomics pages 1-2)
Single-cell/spatial/CRISPR: No mature XFS single-cell atlas, spatial transcriptomic reference, or replicated genome-wide functional screen was identified. These are priority gaps.

Suggested GO terms include extracellular matrix organization, elastic-fiber assembly, collagen fibril organization, TGF-β receptor signaling, response to oxidative stress, autophagy, lysosomal transport, proteasomal protein catabolism, mitochondrial electron transport, and inflammatory response. Suggested CL concepts include lens epithelial cell, non-pigmented ciliary epithelial cell, iris pigment epithelial cell, trabecular-meshwork cell, corneal endothelial cell, fibroblast, and retinal ganglion cell.

7. Anatomical structures affected

The primary organ is the eye, especially its anterior segment. Principal sites are anterior lens capsule, lens epithelium, iris pigment epithelium and stroma, pupillary sphincter, ciliary epithelium/body, zonular fibers, trabecular meshwork, Schlemm canal region, corneal endothelium, and iris vasculature. Secondary glaucomatous injury affects retinal ganglion cells, optic-nerve head/lamina cribrosa, and visual pathways.

Suggested UBERON concepts: eye, anterior segment of eye, lens capsule, iris, ciliary body, cornea/corneal endothelium, trabecular meshwork, retina, optic nerve. Suggested GO cellular components: extracellular matrix, elastic fiber, basement membrane, endoplasmic reticulum, autophagosome, lysosome, mitochondrion, and proteasome.

XFS may be clinically unilateral, but asymmetric bilateral involvement is common. Histologic deposits have been reported in lung, liver, kidney, gallbladder, skin, heart/pericardiac vessels, and cerebral meninges. Associations with cardiovascular, cerebrovascular, hearing, and systemic vascular disease remain heterogeneous; systemic screening beyond ordinary age-appropriate care is not established solely because XFS is present. (bora2024cardiovascularmanifestationsof pages 7-8, elhawy2012pseudoexfoliationsyndromea pages 1-2)

8. Temporal development

Onset is usually late adult/geriatric and insidious. A practical clinical continuum is: (1) early/asymmetric deposits with normal IOP; (2) established XFS with poor dilation, pigment release, and zonular dysfunction; (3) XFS with ocular hypertension; (4) XFG with structural/functional damage; and (5) advanced glaucoma or lens/IOL-bag instability.

The disorder is chronic and does not spontaneously remit. Apparent unilateral disease can convert to bilateral clinical disease over years. XFG can progress faster than POAG: over three years, one study observed mean-deviation change of −3.17 dB versus −1.25 dB, VFI change of −7.65% versus −1.90%, and guided-progression-analysis progression in 58% versus 13%. Therefore, early recognition and tighter IOP targets are important.

9. Inheritance and population

Inheritance is multifactorial/polygenic, with familial aggregation, incomplete and strongly age-dependent penetrance, and variable expressivity. No conventional carrier state, anticipation, or Mendelian recurrence estimate is appropriate.

Published prevalence ranges from <0.4% to >20%, depending heavily on age, ancestry, geography, examination technique, and study design; approximately 80 million people have been estimated to be affected globally. Latitude examples cited in the gene–environment literature range from 1.1% in Sri Lanka to 22% in Finland, but cross-study methodological differences preclude a simple latitude-prevalence equation. (li2021loxl1genepolymorphisms pages 1-2, pasquale2014considerationforgeneenvironment pages 2-4)

High prevalence has been reported in Nordic, Mediterranean, Russian, Middle Eastern, South Asian, and some Indigenous populations, while XFS is not restricted to any ancestry. LOXL1 haplotypes and risk directions vary geographically. Female predominance appears in some older cohorts but is inconsistent after accounting for longevity and ascertainment; no universal sex ratio should be assigned. Incidence per 100,000/year is not globally standardized.

10. Diagnostics

Diagnosis is clinical:

Slit-lamp examination before and after dilation for pupillary-border and anterior-lens XFM, including the classic central disc/clear intermediate zone/peripheral granular ring.
Assessment of pupil dilation, iris transillumination, pigment dispersion, phacodonesis, lens position, and cataract.
Goldmann applanation tonometry, ideally at different times because IOP fluctuates.
Gonioscopy for angle configuration, trabecular pigmentation, and Sampaolesi line.
Optic-disc examination, OCT RNFL/ganglion-cell analysis, and standard automated perimetry to diagnose/stage XFG.
Pachymetry and corneal endothelial assessment when clinically or surgically indicated.

Differential diagnoses include pigment dispersion syndrome (younger, often male; Krukenberg spindle, mid-peripheral transillumination, posterior iris bowing), uveitic pigment/debris, true capsular exfoliation, amyloid or inflammatory deposits, and primary open-angle/angle-closure glaucoma. XFM on lens/pupil and zonular weakness favor XFS. (rong2024lackofassociation pages 8-9)

There is no recommended routine LOXL1 test: common risk alleles have poor specificity and ancestry-dependent effects. WGS, WES, panels, CMA, karyotyping, FISH, mtDNA, and repeat-expansion testing have no routine diagnostic role. RNA-seq, proteomics, metabolomics, aqueous biomarkers, systemic immune indexes, and liquid biopsy remain research tools.

11. Outcome and prognosis

XFS is not known to shorten life expectancy directly, and disease-specific survival statistics are not applicable. Prognosis is driven by XFG severity, IOP level/fluctuation, baseline field loss, adherence, treatment response, cataract, corneal endothelial reserve, and zonular integrity.

XFG typically presents with higher IOP and more advanced damage and responds less predictably to medication than POAG. Irreversible glaucomatous loss does not recover; cataract-related acuity loss is often reversible, but surgery is technically more hazardous. Lens/IOL-bag dislocation may occur years after cataract surgery. The strongest modifiable prognostic factor is sustained IOP reduction. (aboobakar2022thegeneticsof pages 6-8, borjan2023pseudoexfoliativesyndromein pages 2-3)

12. Treatment

There is no approved disease-modifying treatment that stops XFM production or removes systemic deposits. Management targets complications.

XFS without glaucoma: periodic IOP, optic-nerve, OCT, and field surveillance; document dilation and zonular status.
XFG pharmacotherapy: prostaglandin analogues, beta-blockers, carbonic-anhydrase inhibitors, alpha-2 agonists, and rho-kinase inhibitors according to local glaucoma algorithms. Fixed combinations and preservative-free preparations can reduce treatment burden/ocular-surface toxicity. Pharmacogenomic prescribing is not established.
Laser: SLT is often effective because the trabecular meshwork is pigmented. A 2024 series reported IOP reduction from 26.7 to 18.9 mmHg at three months, a 29.2% reduction and 69.4% success, but durability requires follow-up.
Cataract surgery: phacoemulsification may lower IOP and improves vision when cataract is significant. Surgeons should anticipate small pupil and zonular weakness; iris hooks/rings, capsular hooks, capsular-tension rings, careful hydrodissection, low-stress fluidics, and secure IOL planning may be required. In a Croatian registry, XFS surgery cost was 1.4-fold higher; XFS was associated with longer surgery and more complications. Borjan et al., December 2023, DOI. (borjan2023pseudoexfoliativesyndromein pages 2-3, borjan2023pseudoexfoliativesyndromein pages 12-14)
Incisional glaucoma surgery: trabeculectomy with antifibrotic, glaucoma drainage devices, selected angle surgery/MIGS, and cyclodestruction are options according to stage and target IOP. A 2024 PreserFlo series of 29 Asian XFG eyes reduced mean IOP from 32.6 to 16.9 mmHg and medications from 3.4 to 1.0, but had 31% reoperation and 17% hypotony, warranting caution. Wakuda et al., October 2024, DOI. (wakuda2024postoperativeoutcomesof pages 4-6, wakuda2024postoperativeoutcomesof pages 9-10)

Suggested NCIT intervention concepts: ophthalmic solution, prostaglandin analogue therapy, selective laser trabeculoplasty, phacoemulsification, intraocular-lens implantation, capsular-tension-ring placement, trabeculectomy, glaucoma drainage-device implantation, minimally invasive glaucoma surgery, and cyclophotocoagulation.

Current implementation studies include recruiting CANPEX1 (phacoemulsification versus SLT; NCT04416724; planned n=200) and a Helsinki cataract-plus-iStent versus cataract-plus-SLT study (NCT04635020; planned n=285). A completed observational XEN45 study enrolled 350 participants (NCT06993311), although numerical results were unavailable in the retrieved registry record. These test pressure-lowering strategies, not molecular correction of XFS. (NCT06993311 chunk 1, NCT04416724 chunk 1, NCT04635020 chunk 1)

13. Prevention

Primary: no proven prevention. UV-blocking eyewear is low risk and generally advisable for ocular health, but XFS-specific benefit is unproven. Maintain nutritional folate adequacy rather than prescribing high-dose supplementation. Evidence is insufficient to recommend caffeine restriction solely to prevent XFS.
Secondary: careful dilated slit-lamp examination in older adults, especially those with family history, high-prevalence ancestry/geography, unilateral XFS, ocular hypertension, or unexplained poor dilation. Monitor both eyes.
Tertiary: aggressive individualized IOP control, adherence support, regular fields/OCT, cataract-surgical precautions, and long-term monitoring for late IOL-bag instability.
Not applicable: vaccination, newborn screening, prenatal diagnosis, carrier screening, prophylactic gene therapy, and population genetic screening.

14. Other species and natural disease

No infectious transmission or zoonotic potential exists. A fully validated naturally occurring veterinary counterpart with the characteristic human XFM phenotype is not established. LOXL1 and elastic-fiber biology are evolutionarily conserved, and canine ocular disorders have informed glaucoma research, but canine pigmentary glaucoma should not be annotated as natural XFS without direct pathology.

Mus musculus (NCBI Taxon 10090) LOXL1-deficient models demonstrate systemic elastic-fiber defects and are useful for testing LOXL1 biology. However, they do not consistently reproduce the age-dependent ocular XFM, asymmetric human course, and conversion to XFG. A LOXL1-knockout elastin-homeostasis study is indexed by PMID 32533648. (li2021loxl1genepolymorphisms pages 21-21, bernstein2018exfoliationsyndromea pages 1-4)

15. Model organisms and experimental systems

Human primary cells: XFG patient-derived Tenon fibroblasts reproduce autophagy/lysosome positioning, microtubule, mitochondrial, LOXL1-processing, and clusterin phenotypes. This is presently one of the most disease-relevant mechanistic systems. Limitation: surgery-derived fibroblasts may reflect advanced glaucoma and treatment exposure rather than disease initiation. (bernstein2018exfoliationsyndromea pages 1-4)
Ocular cell culture: lens epithelial, non-pigmented ciliary epithelial, and trabecular-meshwork cells are used for TGF-β, UV, oxidative-stress, cytokine, LOXL1, and ECM experiments. They permit perturbation but do not recreate aging, aqueous dynamics, or multicellular XFM assembly.
LOXL1-null mouse: useful for elastic-fiber and gene-function studies but incompletely phenocopies human XFS.
Human surgical tissue/aqueous humor: lens capsules, iris/ciliary tissue, aqueous humor, and XFM deposits support transcriptomics, proteomics, microscopy, and biochemical studies but are cross-sectional and often late-stage.
Major unmet need: an age-dependent, ancestry-aware animal or organoid model that forms authentic XFM and progresses to ocular hypertension/XFG.

Overall assessment

The authoritative interpretation is that XFS is an age-related systemic ECM aggregopathy with ocularly dominant disease. LOXL1 is central but not determinative; ancestry-dependent allele reversal, high risk-allele prevalence, environmental associations, and impaired stress/proteostasis pathways argue against a simple monogenic enzyme-deficiency model. The most immediate clinical opportunity is not genetic testing but earlier recognition, bilateral surveillance, tighter IOP control, and XFS-aware cataract planning. The principal research priorities are functional resolution of LOXL1 and newer loci, replicated gene–environment interaction studies, single-cell/spatial profiling, conversion biomarkers, faithful models, and therapies that reduce XFM production or restore proteostasis.

References

(li2021loxl1genepolymorphisms pages 1-2): Xiaoyan Li, Jie He, and Jian Sun. Loxl1 gene polymorphisms are associated with exfoliation syndrome/exfoliation glaucoma risk: an updated meta-analysis. PLoS ONE, 16:e0250772, Apr 2021. URL: https://doi.org/10.1371/journal.pone.0250772, doi:10.1371/journal.pone.0250772. This article has 27 citations and is from a peer-reviewed journal.
(bernstein2018exfoliationsyndromea pages 1-4): Audrey M. Bernstein, Robert Ritch, and Jose M. Wolosin. Exfoliation syndrome: a disease of autophagy and loxl1 proteopathy. Journal of glaucoma, 27 Suppl 1:S44-S53, Jul 2018. URL: https://doi.org/10.1097/ijg.0000000000000919, doi:10.1097/ijg.0000000000000919. This article has 34 citations and is from a peer-reviewed journal.
(elhawy2012pseudoexfoliationsyndromea pages 1-2): Eman Elhawy, Gautam Kamthan, Cecilia Q Dong, and John Danias. Pseudoexfoliation syndrome, a systemic disorder with ocular manifestations. Human Genomics, Oct 2012. URL: https://doi.org/10.1186/1479-7364-6-22, doi:10.1186/1479-7364-6-22. This article has 197 citations and is from a peer-reviewed journal.
(OpenTargets Search: pseudoexfoliation syndrome,exfoliation glaucoma-LOXL1): Open Targets Query (pseudoexfoliation syndrome,exfoliation glaucoma-LOXL1, 2 results). Buniello, A. et al. (2025). Open Targets Platform: facilitating therapeutic hypotheses building in drug discovery. Nucleic Acids Research.
(aung2017geneticassociationstudy pages 24-38): Tin Aung, Mineo Ozaki, Mei Chin Lee, Ursula Schlötzer-Schrehardt, Gudmar Thorleifsson, Takanori Mizoguchi, Robert P Igo, Aravind Haripriya, Susan E Williams, Yury S Astakhov, Andrew C Orr, Kathryn P Burdon, Satoko Nakano, Kazuhiko Mori, Khaled Abu-Amero, Michael Hauser, Zheng Li, Gopalakrishnan Prakadeeswari, Jessica N Cooke Bailey, Alina Popa Cherecheanu, Jae H Kang, Sarah Nelson, Ken Hayashi, Shin-ichi Manabe, Shigeyasu Kazama, Tomasz Zarnowski, Kenji Inoue, Murat Irkec, Miguel Coca-Prados, Kazuhisa Sugiyama, Irma Järvelä, Patricio Schlottmann, S Fabian Lerner, Hasnaa Lamari, Yildirim Nilgün, Mukharram Bikbov, Ki Ho Park, Soon Cheol Cha, Kenji Yamashiro, Juan C Zenteno, Jost B Jonas, Rajesh S Kumar, Shamira A Perera, Anita S Y Chan, Nino Kobakhidze, Ronnie George, Lingam Vijaya, Tan Do, Deepak P Edward, Lourdes de Juan Marcos, Mohammad Pakravan, Sasan Moghimi, Ryuichi Ideta, Daniella Bach-Holm, Per Kappelgaard, Barbara Wirostko, Samuel Thomas, Daniel Gaston, Karen Bedard, Wenda L Greer, Zhenglin Yang, Xueyi Chen, Lulin Huang, Jinghong Sang, Hongyan Jia, Liyun Jia, Chunyan Qiao, Hui Zhang, Xuyang Liu, Bowen Zhao, Ya-Xing Wang, Liang Xu, Stéphanie Leruez, Pascal Reynier, George Chichua, Sergo Tabagari, Steffen Uebe, Matthias Zenkel, Daniel Berner, Georg Mossböck, Nicole Weisschuh, Ursula Hoja, Ulrich-Christoph Welge-Luessen, Christian Mardin, Panayiota Founti, Anthi Chatzikyriakidou, Theofanis Pappas, Eleftherios Anastasopoulos, Alexandros Lambropoulos, Arkasubhra Ghosh, Rohit Shetty, Natalia Porporato, Vijayan Saravanan, Rengaraj Venkatesh, Chandrashekaran Shivkumar, Narendran Kalpana, Sripriya Sarangapani, Mozhgan R Kanavi, Afsaneh Naderi Beni, Shahin Yazdani, Alireza lashay, Homa Naderifar, Nassim Khatibi, Antonio Fea, Carlo Lavia, Laura Dallorto, Teresa Rolle, Paolo Frezzotti, Daniela Paoli, Erika Salvi, Paolo Manunta, Yosai Mori, Kazunori Miyata, Tomomi Higashide, Etsuo Chihara, Satoshi Ishiko, Akitoshi Yoshida, Masahide Yanagi, Yoshiaki Kiuchi, Tsutomu Ohashi, Toshiya Sakurai, Takako Sugimoto, Hideki Chuman, Makoto Aihara, Masaru Inatani, Masahiro Miyake, Norimoto Gotoh, Fumihiko Matsuda, Nagahisa Yoshimura, Yoko Ikeda, Morio Ueno, Chie Sotozono, Jin Wook Jeoung, Min Sagong, Kyu Hyung Park, Jeeyun Ahn, Marisa Cruz-Aguilar, Sidi M Ezzouhairi, Abderrahman Rafei, Yaan Fun Chong, Xiao Yu Ng, Shuang Ru Goh, Yueming Chen, Victor H K Yong, Muhammad Imran Khan, Olusola O Olawoye, Adeyinka O Ashaye, Idakwo Ugbede, Adeola Onakoya, Nkiru Kizor-Akaraiwe, Chaiwat Teekhasaenee, Yanin Suwan, Wasu Supakontanasan, Suhanya Okeke, Nkechi J Uche, Ifeoma Asimadu, Humaira Ayub, Farah Akhtar, Ewa Kosior-Jarecka, Urszula Lukasik, Ignacio Lischinsky, Vania Castro, Rodolfo Perez Grossmann, Gordana Sunaric Megevand, Sylvain Roy, Edward Dervan, Eoin Silke, Aparna Rao, Priti Sahay, Pablo Fornero, Osvaldo Cuello, Delia Sivori, Tamara Zompa, Richard A Mills, Emmanuelle Souzeau, Paul Mitchell, Jie Jin Wang, Alex W Hewitt, Michael Coote, Jonathan G Crowston, Sergei Y Astakhov, Eugeny L Akopov, Anton Emelyanov, Vera Vysochinskaya, Gyulli Kazakbaeva, Rinat Fayzrakhmanov, Saleh A Al-Obeidan, Ohoud Owaidhah, Leyla Ali Aljasim, Balram Chowbay, Jia Nee Foo, Raphael Q Soh, Kar Seng Sim, Zhicheng Xie, Augustine W O Cheong, Shi Qi Mok, Hui Meng Soo, Xiao Yin Chen, Su Qin Peh, Khai Koon Heng, Rahat Husain, Su-Ling Ho, Axel M Hillmer, Ching-Yu Cheng, Francisco A Escudero-Domínguez, Rogelio González-Sarmiento, Frederico Martinon-Torres, Antonio Salas, Kessara Pathanapitoon, Linda Hansapinyo, Boonsong Wanichwecharugruang, Naris Kitnarong, Anavaj Sakuntabhai, Hip X Nguyn, Giang T T Nguyn, Trình V Nguyn, Werner Zenz, Alexander Binder, Daniela S Klobassa, Martin L Hibberd, Sonia Davila, Stefan Herms, Markus M Nöthen, Susanne Moebus, Robyn M Rautenbach, Ari Ziskind, Trevor R Carmichael, Michele Ramsay, Lydia Álvarez, Montserrat García, Héctor González-Iglesias, Pedro P Rodríguez-Calvo, Luis Fernández-Vega Cueto, Çilingir Oguz, Nevbahar Tamcelik, Eray Atalay, Bilge Batu, Dilek Aktas, Burcu Kasım, M Roy Wilson, Anne L Coleman, Yutao Liu, Pratap Challa, Leon Herndon, Rachel W Kuchtey, John Kuchtey, Karen Curtin, Craig J Chaya, Alan Crandall, Linda M Zangwill, Tien Yin Wong, Masakazu Nakano, Shigeru Kinoshita, Anneke I den Hollander, Eija Vesti, John H Fingert, Richard K Lee, Arthur J Sit, Bradford J Shingleton, Ningli Wang, Daniele Cusi, Raheel Qamar, Peter Kraft, Margaret A Pericak-Vance, Soumya Raychaudhuri, Steffen Heegaard, Tero Kivelä, André Reis, Friedrich E Kruse, Robert N Weinreb, Louis R Pasquale, Jonathan L Haines, Unnur Thorsteinsdottir, Fridbert Jonasson, R Rand Allingham, Dan Milea, Robert Ritch, Toshiaki Kubota, Kei Tashiro, Eranga N Vithana, Shazia Micheal, Fotis Topouzis, Jamie E Craig, Michael Dubina, Periasamy Sundaresan, Kari Stefansson, Janey L Wiggs, Francesca Pasutto, and Chiea Chuen Khor. Genetic association study of exfoliation syndrome identifies a protective rare variant at loxl1 and five new susceptibility loci. Nature Genetics, 49:993-1004, May 2017. URL: https://doi.org/10.1038/ng.3875, doi:10.1038/ng.3875. This article has 185 citations and is from a highest quality peer-reviewed journal.
(aboobakar2022thegeneticsof pages 6-8): Inas F. Aboobakar and Janey L. Wiggs. The genetics of glaucoma: disease associations, personalised risk assessment and therapeutic opportunities‐a review. Clinical & Experimental Ophthalmology, 50:143-162, Jan 2022. URL: https://doi.org/10.1111/ceo.14035, doi:10.1111/ceo.14035. This article has 64 citations and is from a peer-reviewed journal.
(pasquale2014considerationforgeneenvironment pages 4-6): Louis R. Pasquale, Jae H. Kang, and Janey L. Wiggs. Consideration for gene-environment interactions as novel determinants of exfoliation syndrome. International Ophthalmology Clinics, 54:29–41, Jan 2014. URL: https://doi.org/10.1097/iio.0000000000000040, doi:10.1097/iio.0000000000000040. This article has 11 citations and is from a peer-reviewed journal.
(pasquale2014solarexposureand pages 1-2): Louis R. Pasquale, Aliya Z. Jiwani, Tzukit Zehavi-Dorin, Arow Majd, Douglas J. Rhee, Teresa Chen, Angela Turalba, Lucy Shen, Stacey Brauner, Cynthia Grosskreutz, Matthew Gardiner, Sherleen Chen, Sheila Borboli-Gerogiannis, Scott H. Greenstein, Kenneth Chang, Robert Ritch, Stephanie Loomis, Jae H. Kang, Janey L. Wiggs, and Hani Levkovitch-Verbin. Solar exposure and residential geographic history in relation to exfoliation syndrome in the united states and israel. JAMA ophthalmology, 132 12:1439-45, Dec 2014. URL: https://doi.org/10.1001/jamaophthalmol.2014.3326, doi:10.1001/jamaophthalmol.2014.3326. This article has 93 citations and is from a highest quality peer-reviewed journal.
(pasquale2014considerationforgeneenvironment pages 2-4): Louis R. Pasquale, Jae H. Kang, and Janey L. Wiggs. Consideration for gene-environment interactions as novel determinants of exfoliation syndrome. International Ophthalmology Clinics, 54:29–41, Jan 2014. URL: https://doi.org/10.1097/iio.0000000000000040, doi:10.1097/iio.0000000000000040. This article has 11 citations and is from a peer-reviewed journal.
(kang2020cohortstudyof pages 6-7): Jae H. Kang, Trang VoPham, Francine Laden, Bernard A. Rosner, Barbara Wirostko, Robert Ritch, Janey L. Wiggs, Abrar Qureshi, Hongmei Nan, and Louis R. Pasquale. Cohort study of non-melanoma skin cancer and the risk of exfoliation glaucoma. Journal of Glaucoma, 29:448-455, Mar 2020. URL: https://doi.org/10.1097/ijg.0000000000001496, doi:10.1097/ijg.0000000000001496. This article has 13 citations and is from a peer-reviewed journal.
(rong2024lackofassociation pages 8-9): Shisong Rong and Xinting Yu. Lack of association between loxl1 variants and pigment dispersion syndrome/pigmentary glaucoma: a meta-analysis. Genes, 15:161, Jan 2024. URL: https://doi.org/10.3390/genes15020161, doi:10.3390/genes15020161. This article has 3 citations.
(borjan2023pseudoexfoliativesyndromein pages 2-3): Ivan Borjan, Robert Stanić, Ivna Pleština-Borjan, Maja Pavić, Silvia N. W. Hertzberg, Ljubo Znaor, Beáta Éva Petrovski, and Goran Petrovski. Pseudoexfoliative syndrome in cataract surgery—a quality register study and health economic analysis in the split-dalmatia county, croatia. Journal of Clinical Medicine, 13:38, Dec 2023. URL: https://doi.org/10.3390/jcm13010038, doi:10.3390/jcm13010038. This article has 8 citations.
(shyam2023geneticandepigenetic pages 43-47): KR Shyam and DP Alone. Genetic and epigenetic regulation of candidate genes associated with pseudoexfoliation. Unknown journal, 2023.
(borras2018growthfactorsoxidative pages 8-10): Teresa Borrás. Growth factors, oxidative damage, and inflammation in exfoliation syndrome. Journal of Glaucoma, 27:S54-S60, Jul 2018. URL: https://doi.org/10.1097/ijg.0000000000000904, doi:10.1097/ijg.0000000000000904. This article has 28 citations and is from a peer-reviewed journal.
(mullany2022rnasequencingof pages 1-2): Sean Mullany, Henry Marshall, Tiger Zhou, Daniel Thomson, Joshua M. Schmidt, Ayub Qassim, Lachlan S. W. Knight, Georgina Hollitt, Ella C. Berry, Thi Nguyen, Minh-Son To, David Dimasi, Abraham Kuot, Joshua Dubowsky, Rhys Fogarty, Michelle Sun, Luke Chehade, Shilpa Kuruvilla, Devaraj Supramaniam, James Breen, Shiwani Sharma, John Landers, Stewart Lake, Richard A. Mills, Mark M. Hassall, Weng O. Chan, Sonja Klebe, Emmanuelle Souzeau, Owen M. Siggs, and Jamie E. Craig. Rna sequencing of lens capsular epithelium implicates novel pathways in pseudoexfoliation syndrome. Mar 2022. URL: https://doi.org/10.1167/iovs.63.3.26, doi:10.1167/iovs.63.3.26. This article has 11 citations.
(wakuda2024postoperativeoutcomesof pages 4-6): Hiroyuki Wakuda, Ryota Aoki, and Shunsuke Nakakura. Postoperative outcomes of preserflo microshunt in patients with exfoliation glaucoma. Oct 2024. URL: https://doi.org/10.3390/jcm13206132, doi:10.3390/jcm13206132. This article has 6 citations.
(borjan2023pseudoexfoliativesyndromein pages 12-14): Ivan Borjan, Robert Stanić, Ivna Pleština-Borjan, Maja Pavić, Silvia N. W. Hertzberg, Ljubo Znaor, Beáta Éva Petrovski, and Goran Petrovski. Pseudoexfoliative syndrome in cataract surgery—a quality register study and health economic analysis in the split-dalmatia county, croatia. Journal of Clinical Medicine, 13:38, Dec 2023. URL: https://doi.org/10.3390/jcm13010038, doi:10.3390/jcm13010038. This article has 8 citations.
(NCT04635020 chunk 1): Prof. Mika Harju. Comparison Of iStent to Laser in Exfoliation Glaucoma Helsinki Study Group. Helsinki University Central Hospital. 2020. ClinicalTrials.gov Identifier: NCT04635020
(NCT04416724 chunk 1): Phacoemulsification vs SLT as Initial Treatment for Pseudoexfoliation Glaucoma. Nova Scotia Health Authority. 2022. ClinicalTrials.gov Identifier: NCT04416724
(kang2022prediagnosticplasmametabolomics pages 1-2): Jae H. Kang, Oana Zeleznik, Lisa Frueh, Jessica Lasky-Su, A. Heather Eliassen, Clary Clish, Bernard A. Rosner, Louis R. Pasquale, and Janey L. Wiggs. Prediagnostic plasma metabolomics and the risk of exfoliation glaucoma. Aug 2022. URL: https://doi.org/10.1167/iovs.63.9.15, doi:10.1167/iovs.63.9.15. This article has 10 citations.
(NCT06993311 chunk 1): SARA POSE BAZARRA. Real World Evidence of Xen45 Gel Implant in Pseudoexfoliation Glaucoma. Xerencia de Xestión Integrada de Ferrol. 2018. ClinicalTrials.gov Identifier: NCT06993311
(li2021loxl1genepolymorphisms pages 21-21): Xiaoyan Li, Jie He, and Jian Sun. Loxl1 gene polymorphisms are associated with exfoliation syndrome/exfoliation glaucoma risk: an updated meta-analysis. PLoS ONE, 16:e0250772, Apr 2021. URL: https://doi.org/10.1371/journal.pone.0250772, doi:10.1371/journal.pone.0250772. This article has 27 citations and is from a peer-reviewed journal.
(kang2020cohortstudyof pages 2-3): Jae H. Kang, Trang VoPham, Francine Laden, Bernard A. Rosner, Barbara Wirostko, Robert Ritch, Janey L. Wiggs, Abrar Qureshi, Hongmei Nan, and Louis R. Pasquale. Cohort study of non-melanoma skin cancer and the risk of exfoliation glaucoma. Journal of Glaucoma, 29:448-455, Mar 2020. URL: https://doi.org/10.1097/ijg.0000000000001496, doi:10.1097/ijg.0000000000001496. This article has 13 citations and is from a peer-reviewed journal.
(bora2024cardiovascularmanifestationsof pages 7-8): Rajal R Bora, Roshan Prasad, Swapneel Mathurkar, Kashish Bhojwani, and Akshansh Prasad. Cardiovascular manifestations of pseudoexfoliation syndrome: a narrative review. Cureus, Jan 2024. URL: https://doi.org/10.7759/cureus.51492, doi:10.7759/cureus.51492. This article has 10 citations.
(wakuda2024postoperativeoutcomesof pages 9-10): Hiroyuki Wakuda, Ryota Aoki, and Shunsuke Nakakura. Postoperative outcomes of preserflo microshunt in patients with exfoliation glaucoma. Oct 2024. URL: https://doi.org/10.3390/jcm13206132, doi:10.3390/jcm13206132. This article has 6 citations.

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Exfoliation Syndrome: Disease Characteristics Research Report

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