Familial Exudative Vitreoretinopathy

Mendelian MONDO:0019516 Pathograph 9 Show in embeddings browser Ophthalmological Disease Retinal vascular disorder

Familial exudative vitreoretinopathy (FEVR) is a rare inherited vitreoretinopathy characterized by incomplete or arrested vascularization of the peripheral retina. The shared core mechanism is impaired Norrin/beta-catenin (Wnt) signaling in retinal vascular endothelial cells, which is required for developmental angiogenesis of the peripheral retina and establishment of the blood-retina barrier. The resulting peripheral avascular zone causes retinal ischemia, which drives compensatory neovascularization, exudation, hemorrhage, vitreoretinal traction, and tractional or exudative retinal detachment. FEVR is genetically heterogeneous: most cases are autosomal dominant (FZD4, LRP5, TSPAN12), but autosomal recessive (LRP5, TSPAN12) and X-linked recessive (NDP) forms occur, and KIF11 variants produce a FEVR-like retinal phenotype within a broader microcephaly-lymphedema-chorioretinal dysplasia spectrum. Expressivity is highly variable, ranging from an asymptomatic avascular periphery detectable only by fluorescein angiography to bilateral blindness, even within the same family. NDP variants additionally cause Norrie disease (a severe allelic disorder), and recessive LRP5 disease can be accompanied by reduced bone mineral density.

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3
Inheritance
5
Pathophys.
20
Phenotypes
9
Pathograph
7
Genes
4
Medical Actions
5
Subtypes
1
Trials
11
References
1
Deep Research
👪

Inheritance

3
Autosomal dominant inheritance HP:0000006
The most common mode of inheritance for FEVR, seen with FZD4, LRP5, TSPAN12, and KIF11 variants. Penetrance is reduced and expressivity is highly variable.
Autosomal dominant inheritance
Show evidence (2 references)
PMID:29633588 SUPPORT Human Clinical
"these can be inherited in an autosomal dominant (most common), autosomal recessive, and X-linked recessive fashion"
A clinical review confirms autosomal dominant inheritance is the most common FEVR mode.
PMID:20301326 SUPPORT Human Clinical
"Offspring of an affected individual are at a 50% risk of inheriting the pathogenic variant, but many individuals with adFEVR can be asymptomatic because of reduced penetrance."
GeneReviews genetic counseling section confirms 50% recurrence risk and reduced penetrance in autosomal dominant FEVR.
X-linked recessive inheritance HP:0001419
The NDP-related form is inherited in an X-linked recessive manner, affecting predominantly males; NDP is allelic with Norrie disease.
X-linked recessive inheritance
Show evidence (1 reference)
PMID:29633588 SUPPORT Human Clinical
"these can be inherited in an autosomal dominant (most common), autosomal recessive, and X-linked recessive fashion"
A clinical review confirms the X-linked recessive FEVR mode of inheritance (NDP).
Autosomal recessive inheritance HP:0000007
Recessive FEVR occurs with biallelic LRP5 (and TSPAN12) variants; recessive LRP5 disease is associated with reduced bone mineral density.
Autosomal recessive inheritance
Show evidence (1 reference)
PMID:16929062 SUPPORT Human Clinical
"homozygous mutations in LRP5 have recently been reported as underlying the recessive form of this disease"
Documents the autosomal recessive form of FEVR caused by biallelic LRP5 mutations.
◆

Subtypes

5
FZD4-Related FEVR (EVR1, autosomal dominant)
FZD4 hgnc:4042
Autosomal dominant FEVR caused by heterozygous pathogenic variants in FZD4, encoding the frizzled-4 receptor, the obligate Norrin receptor. One of the most common molecularly defined forms of adFEVR. Variants impair Norrin/FZD4 signaling and peripheral retinal vascularization.
LRP5-Related FEVR (EVR4, AD or AR; with reduced bone density)
LRP5 hgnc:6697
FEVR caused by pathogenic variants in LRP5, encoding the Wnt co-receptor low-density lipoprotein receptor-related protein 5. Inherited dominantly or recessively; recessive disease is frequently accompanied by reduced bone mineral density, reflecting LRP5's role in skeletal Wnt signaling.
TSPAN12-Related FEVR (EVR5)
TSPAN12 hgnc:21641
FEVR caused by variants in TSPAN12, encoding tetraspanin-12, an essential co-receptor of the Norrin/FZD4 complex that amplifies FZD4 ligand selectivity and signaling. Mostly autosomal dominant.
NDP-Related FEVR (EVR2, X-linked recessive)
NDP hgnc:7678
X-linked recessive FEVR caused by hemizygous variants in NDP, encoding the secreted ligand Norrin. NDP is allelic with Norrie disease; FEVR represents the milder end of the NDP phenotypic spectrum, affecting predominantly males.
KIF11-Related FEVR (MLCRD/CDMMR spectrum)
KIF11 hgnc:6388
Autosomal dominant FEVR-like retinal phenotype caused by heterozygous variants in KIF11, encoding a kinesin motor. Often part of a broader syndrome (microcephaly, lymphedema, chorioretinal dysplasia), and FEVR cases should be inspected for microcephaly as a marker of KIF11-related disease.
⚙

Pathophysiology

5
Impaired Norrin/beta-catenin signaling in retinal endothelium
The core defect of FEVR. Norrin (NDP) is a secreted ligand that binds the frizzled-4 (FZD4) receptor together with the co-receptor LRP5 and the accessory tetraspanin TSPAN12, activating canonical (beta-catenin-dependent) Wnt signaling specifically in retinal vascular endothelial cells. Loss-of-function in any of these components reduces beta-catenin signaling output. Disruption of Tspan12, Ndp, Fzd4, or Lrp5 in mice produces similar ocular phenotypes, indicating a shared signaling pathway.
retinal blood vessel endothelial cell CL:0002585
FZD4 hgnc:4042 ↓ DECREASED
Norrin signaling pathway GO:0110135 ↓ DECREASED canonical Wnt signaling pathway GO:0060070 ↓ DECREASED
Downstream
Incomplete peripheral retinal vascularization Reduced Norrin/beta-catenin signaling impairs developmental angiogenesis of the peripheral retina, leaving an avascular peripheral zone.
Inner Blood-Retinal Barrier Dysfunction Reduced Norrin/beta-catenin signaling also impairs formation and maintenance of the inner blood-retinal barrier (iBRB) in retinal endothelial cells, contributing to vascular permeability and retinal exudation.
Show evidence (2 references)
PMID:28658627 SUPPORT Model Organism
"Gene disruptions of Tspan12 (Junge et al., 2009), Ndp (Luhmann et al., 2005), Fzd4 (Xu et al., 2004; Ye et al., 2009), and Lrp5 (Xia et al., 2008) all result in similar ocular phenotypes in mice, characterized by defects in intraretinal capillary development and dysregulation of the blood-retina barrier."
Shows the convergent ocular phenotype across all four core Norrin-pathway genes, defining the shared mechanism.
PMID:28658627 SUPPORT In Vitro
"TSPAN12 is an essential component of the NDP receptor complex and interacts with FZD4 and NDP via its extracellular loops, consistent with an action as co-receptor that enhances FZD4 ligand selectivity for NDP."
Establishes the molecular assembly of the Norrin/FZD4/TSPAN12 receptor complex underlying the pathway.
Incomplete peripheral retinal vascularization
The hallmark structural lesion of FEVR: failure of the retinal vasculature to grow into the peripheral retina, producing a bilateral peripheral avascular zone. This avascularity is probably present from birth and is detectable by fundus fluorescein angiography even in asymptomatic individuals.
retinal blood vessel endothelial cell CL:0002585
retina vasculature development in camera-type eye GO:0061298 ↓ DECREASED establishment of blood-retinal barrier GO:1990963 ↓ DECREASED
Downstream
Peripheral retinal ischemia and neovascular response The non-perfused peripheral retina becomes ischemic, generating a pro-angiogenic drive (e.g., VEGF) that triggers abnormal neovascularization.
Peripheral retinal avascularization The same developmental vascularization failure is recorded clinically as peripheral retinal avascularization.
Show evidence (1 reference)
PMID:29633588 SUPPORT Human Clinical
"The principal feature of the disease is an avascular peripheral retina."
Identifies the peripheral avascular retina as the principal structural feature of FEVR.
Peripheral retinal ischemia and neovascular response
Ischemia of the peripheral avascular retina drives pathological neovascularization, with exudation and hemorrhage. These vascular sequelae are the proximate cause of the symptomatic complications of FEVR.
capillary endothelial cell CL:0002144
angiogenesis GO:0001525 ↑ INCREASED
Downstream
Vitreoretinal traction and retinal detachment Fibrovascular proliferation and contraction exert tractional forces on the retina, and exudation accumulates, producing tractional, rhegmatogenous, or exudative retinal detachment and ultimately vision loss.
Show evidence (1 reference)
PMID:29633588 SUPPORT Human Clinical
"This in turn can cause further pathological changes including neovascularization, exudation, hemorrhage, and retinal detachment."
Documents neovascularization, exudation, and hemorrhage as ischemia-driven sequelae.
Vitreoretinal traction and retinal detachment
Terminal convergence of FEVR: fibrovascular traction and exudation cause macular dragging, falciform retinal folds, and partial or total retinal detachment, leading to severe visual impairment or blindness. Expressivity is highly variable.
capillary endothelial cell CL:0002144
retinal blood vessel morphogenesis GO:0061304 ↕ DYSREGULATED
Downstream
Tractional retinal detachment Fibrovascular traction is the proximate mechanism for tractional retinal detachment.
Reduced visual acuity Retinal detachment, exudation, and macular involvement reduce visual acuity in symptomatic FEVR.
Show evidence (1 reference)
PMID:25124931 SUPPORT Human Clinical
"macular dragging, partial retinal detachment, falciform folds, or total retinal detachment"
Catalogs the tractional retinal sequelae that define advanced FEVR.
Inner Blood-Retinal Barrier Dysfunction
Norrin/Wnt signaling in retinal endothelial cells governs not only developmental angiogenesis but also formation and maintenance of the inner blood-retinal barrier (iBRB). Loss-of-function in FZD4, LRP5, NDP, or TSPAN12 impairs iBRB integrity, producing aberrant vascular permeability that contributes to retinal exudation independently of ischemia-driven neovascularization. FEVR, Norrie disease, and persistent fetal vascular syndrome share this iBRB dysfunction as a unifying pathophysiological element.
retinal blood vessel endothelial cell CL:0002585
establishment of blood-retinal barrier GO:1990963 ↓ DECREASED
Show evidence (1 reference)
DOI:10.3390/cells12212579 SUPPORT Other
"unified by abnormal retinal endothelial cell function, and subsequent irregular retinal vascular development and/or aberrant inner blood-retinal-barrier (iBRB) function"
Establishes iBRB dysfunction as a distinct pathophysiological element shared across FEVR-related disorders, driven by abnormal Norrin/Wnt signaling in retinal endothelial cells.
⬡

Pathograph

Use the checkboxes to hide or show graph categories. Hover nodes for evidence and cross-linked metadata.
Pathograph: causal mechanism network for Familial Exudative Vitreoretinopathy Interactive directed graph showing how pathophysiology mechanisms, phenotypes, genetic factors and variants, experimental models, environmental triggers, and treatments relate through causal and linked edges.
●

Phenotypes

20
Eye 6
Retinal detachment Retinal detachment HP:0000541
Course: PROGRESSIVE
Show evidence (1 reference)
PMID:25124931 SUPPORT Human Clinical
"Retinal detachment with avascularity of the peripheral retina, typically associated with familial exudative vitreoretinopathy (FEVR)"
Associates retinal detachment with peripheral avascularity in FEVR.
Vitreoretinopathy OBLIGATE Vitreoretinopathy HP:0007773
Show evidence (1 reference)
ORPHA:891 SUPPORT Other
"HP:0007773 | Vitreoretinopathy | Obligate (100%)"
Orphanet records vitreoretinopathy as an obligate FEVR phenotype.
Reduced visual acuity FREQUENT Reduced visual acuity HP:0007663
Show evidence (1 reference)
ORPHA:891 SUPPORT Other
"HP:0007663 | Reduced visual acuity | Frequent (79-30%)"
Orphanet records reduced visual acuity as a frequent FEVR phenotype.
Nystagmus Nystagmus HP:0000639
Show evidence (1 reference)
PMID:16929062 SUPPORT Human Clinical
"vasculature remnants, and nystagmus were features of the phenotype"
Reports nystagmus as a feature of the recessive LRP5-related FEVR phenotype.
Myopia FREQUENT Myopia HP:0000545
Show evidence (1 reference)
DOI:10.1111/aos.16701 SUPPORT Human Clinical
"Myopia seemed to be overly common in FZD4‐variant‐positive individuals."
Finnish natural history study documents myopia as a frequent finding in FZD4-variant-positive individuals (62% of study eyes).
Strabismus OCCASIONAL Strabismus HP:0000486
Show evidence (1 reference)
DOI:10.1186/s12886-022-02522-8 SUPPORT Human Clinical
"20% (n = 67) was diagnosed of strabismus at first visit"
Among 335 single-gene positive infant FEVR cases, 20% presented with strabismus at first clinical visit.
Head and Neck 1
Microcephaly Microcephaly HP:0000252
Show evidence (1 reference)
PMID:25124931 SUPPORT Human Clinical
"Cases of FEVR should be carefully inspected for the presence of microcephaly as a marker for KIF11-related disease"
Identifies microcephaly as a marker distinguishing KIF11-related FEVR.
Musculoskeletal 1
Reduced bone mineral density Reduced bone mineral density HP:0004349
Show evidence (1 reference)
PMID:16929062 SUPPORT Human Clinical
"Assessment of a patient with a provisional diagnosis of FEVR should therefore include investigation of BMD, with reduced levels suggestive of an underlying LRP5 mutation."
Establishes reduced bone mineral density as a feature of LRP5-related recessive FEVR.
Other 12
Exudative vitreoretinopathy Exudative vitreoretinopathy HP:0030490
Show evidence (1 reference)
PMID:29633588 SUPPORT Human Clinical
"Familial exudative vitreoretinopathy (FEVR) is a heritable vitreoretinopathy characterized by anomalous retinal vascular development."
Defines FEVR as an exudative vitreoretinopathy with anomalous retinal vascular development.
Peripheral retinal neovascularization Peripheral retinal neovascularization HP:0030667
Show evidence (1 reference)
PMID:29633588 SUPPORT Human Clinical
"This in turn can cause further pathological changes including neovascularization, exudation, hemorrhage, and retinal detachment."
Documents neovascularization as a complication of the avascular periphery.
Retinal exudate Retinal exudate HP:0001147
Show evidence (1 reference)
PMID:29633588 SUPPORT Human Clinical
"This in turn can cause further pathological changes including neovascularization, exudation, hemorrhage, and retinal detachment."
Lists exudation among the pathological changes of FEVR.
Falciform retinal fold Falciform retinal fold HP:0001493
Show evidence (1 reference)
PMID:25124931 SUPPORT Human Clinical
"macular dragging, partial retinal detachment, falciform folds, or total retinal detachment"
Falciform folds are documented among the tractional retinal manifestations.
Peripheral retinal avascularization VERY_FREQUENT Avascular peripheral retina HP:0007685
Show evidence (2 references)
PMID:20301326 SUPPORT Human Clinical
"bilateral peripheral retinal avascularity, seen temporally, by indirect ophthalmoscope and scleral indentation, or by fundus fluorescein angiography"
GeneReviews defines bilateral peripheral retinal avascularity as the diagnostic hallmark of FEVR.
ORPHA:891 SUPPORT Other
"HP:0007685 | Peripheral retinal avascularization | Very frequent (99-80%)"
Orphanet records peripheral retinal avascularization as a very frequent FEVR phenotype.
Tractional retinal detachment FREQUENT Tractional retinal detachment HP:0007917
Show evidence (1 reference)
ORPHA:891 SUPPORT Other
"HP:0007917 | Tractional retinal detachment | Frequent (79-30%)"
Orphanet records tractional retinal detachment as a frequent FEVR phenotype.
Macular exudate OCCASIONAL Macular exudate HP:0030496
Show evidence (1 reference)
ORPHA:891 SUPPORT Other
"HP:0030496 | Macular exudate | Occasional (29-5%)"
Orphanet records macular exudate as an occasional FEVR phenotype.
Remnants of the hyaloid vascular system Remnants of the hyaloid vascular system HP:0007968
Show evidence (1 reference)
PMID:16929062 SUPPORT Human Clinical
"Reduced BMD, hyaloid vasculature remnants, and nystagmus were features of the phenotype."
Documents hyaloid vasculature remnants in a recessive LRP5 FEVR family.
Vitreous hemorrhage OCCASIONAL Vitreous hemorrhage HP:0007902
Show evidence (1 reference)
ORPHA:891 SUPPORT Other
"HP:0007902 | Vitreous hemorrhage | Occasional (29-5%)"
Orphanet records vitreous hemorrhage as an occasional FEVR phenotype.
Abnormality of the optic disc FREQUENT Abnormal optic disc morphology HP:0012795
Show evidence (1 reference)
ORPHA:891 SUPPORT Other
"HP:0012795 | Abnormality of the optic disc | Frequent (79-30%)"
Orphanet records abnormality of the optic disc as a frequent FEVR phenotype.
Retinal neovascularization FREQUENT Retinal neovascularization HP:0030666
Show evidence (1 reference)
ORPHA:891 SUPPORT Other
"HP:0030666 | Retinal neovascularization | Frequent (79-30%)"
Orphanet records retinal neovascularization as a frequent FEVR phenotype.
Subretinal fluid FREQUENT Subretinal fluid HP:0031526
Show evidence (1 reference)
ORPHA:891 SUPPORT Other
"HP:0031526 | Subretinal fluid | Frequent (79-30%)"
Orphanet records subretinal fluid as a frequent FEVR phenotype.
🧬

Genetic Associations

7
FZD4 frizzled-4 receptor defect
Gene: FZD4 hgnc:4042 relationship_type: CAUSATIVE
Show evidence (1 reference)
PMID:15035989 SUPPORT Model Organism
"One form of FEVR is caused by defects in Frizzled-4 (Fz4), a presumptive Wnt receptor."
Identifies FZD4 (Fz4) defects as a cause of FEVR.
NDP Norrin ligand defect
Gene: NDP hgnc:7678 relationship_type: CAUSATIVE
Show evidence (1 reference)
PMID:20340138 SUPPORT Human Clinical
"mutations in the gene encoding NDP, a ligand for these Wnt receptors, cause Norrie disease and FEVR"
Confirms NDP (Norrin) ligand mutations cause both FEVR and the allelic Norrie disease.
LRP5 Wnt co-receptor defect
Gene: LRP5 hgnc:6697 relationship_type: CAUSATIVE
Show evidence (1 reference)
PMID:16929062 SUPPORT Human Clinical
"A homozygous LRP5 missense mutation, G550R, was identified in all affected individuals"
Identifies a homozygous LRP5 mutation segregating with recessive FEVR and reduced bone density.
TSPAN12 co-receptor defect
Gene: TSPAN12 hgnc:21641 relationship_type: CAUSATIVE
Show evidence (1 reference)
PMID:28658627 SUPPORT In Vitro
"FEVR-linked mutations in TSPAN12 prevent the incorporation of TSPAN12 into the NDP receptor complex."
Mechanistic study shows FEVR TSPAN12 mutations disrupt assembly of the Norrin receptor complex.
KIF11 kinesin motor defect
Gene: KIF11 hgnc:6388 relationship_type: CAUSATIVE
Show evidence (1 reference)
PMID:25124931 SUPPORT Human Clinical
"The KIF11 gene likely plays a role in retinal vascular development and mutations in this gene can lead to clinical overlap with FEVR."
Identifies KIF11 mutations as a cause of a FEVR-overlapping retinal phenotype.
ZNF408 zinc finger protein defect
Gene: ZNF408 hgnc:20041 relationship_type: CAUSATIVE
Show evidence (1 reference)
DOI:10.3390/cells12212579 SUPPORT Other
"discovery of pathological variants in additional genes such as CTNNB1, KIF11, and ZNF408, some of which operate outside of the Norrin Wnt-signaling pathway"
Identifies ZNF408 as a FEVR causal gene; some variants operate outside the canonical Norrin/Wnt pathway.
CTNNB1 beta-catenin defect
Gene: CTNNB1 hgnc:2514 relationship_type: CAUSATIVE
Show evidence (1 reference)
DOI:10.3390/cells12212579 SUPPORT Other
"discovery of pathological variants in additional genes such as CTNNB1, KIF11, and ZNF408, some of which operate outside of the Norrin Wnt-signaling pathway"
Identifies CTNNB1 as a FEVR causal gene; beta-catenin is the canonical intracellular effector of Wnt signaling.
💊

Medical Actions

4
Laser Photocoagulation
Action: laser photocoagulation Ontology label: Laser Photocoagulation NCIT:C217424
Argon laser photocoagulation of the avascular peripheral retina to induce regression of ischemia-driven new vessel growth and reduce neovascular and exudative sequelae.
Show evidence (1 reference)
PMID:29633588 SUPPORT Human Clinical
"The current treatment paradigm involves laser photocoagulation of the avascular peripheral retina for neovascular sequelae"
Identifies laser photocoagulation of the avascular periphery as the standard treatment for neovascular FEVR.
Peripheral Retinal Cryotherapy
Action: cryosurgery Ontology label: Cryosurgery NCIT:C15215
Cryotherapy of the avascular peripheral retina to induce regression of neovascularization and to stabilize areas of exudate or retinal holes.
Show evidence (1 reference)
PMID:20301326 SUPPORT Human Clinical
"Prophylactic cryotherapy or argon laser photocoagulation to induce regression of new vessel growth caused by ischemia"
GeneReviews documents prophylactic cryotherapy to induce regression of ischemic neovascularization.
Vitreoretinal Surgery
Action: vitrectomy Ontology label: Vitrectomy NCIT:C50837
Vitrectomy and related vitreoretinal surgery to repair tractional or rhegmatogenous retinal detachment in progressive FEVR.
Show evidence (1 reference)
PMID:29633588 SUPPORT Human Clinical
"vitreoretinal surgery for progressive retinal detachment"
Documents vitreoretinal surgery for progressive retinal detachment in FEVR.
Anti-VEGF Therapy
Action: Pharmacotherapy NCIT:C15986
Agent: bevacizumab NCIT:C2039
Intravitreal anti-VEGF agents (e.g., bevacizumab) have been used as an adjunct to suppress ischemia-driven neovascularization and exudation in FEVR.
🔬

Clinical Trials

1
NCT05107921 PHASE_II UNKNOWN
Phase II trial evaluating the efficacy and safety of bromfenac sodium hydrate eye drops in children with FEVR receiving diode laser photocoagulation. Bromfenac is an NSAID (COX inhibitor) used topically to suppress inflammation and exudation following retinal laser treatment.
Target Phenotypes: Peripheral retinal neovascularization HP:0030667
Show evidence (1 reference)
clinicaltrials:NCT05107921 SUPPORT
"This study aims to investigate the efficacy and safety of bromfenac sodium hydrate eye drops in patients with familial exudative vitreoretinopathy receiving diode laser photocoagulation."
Phase II trial assessing bromfenac as an adjunctive NSAID therapy in pediatric FEVR patients undergoing diode laser photocoagulation.
{ }

Source YAML

click to show 
name: Familial Exudative Vitreoretinopathy
creation_date: "2026-06-17T00:00:00Z"
category: Mendelian
description: >-
  Familial exudative vitreoretinopathy (FEVR) is a rare inherited
  vitreoretinopathy characterized by incomplete or arrested vascularization of
  the peripheral retina. The shared core mechanism is impaired Norrin/beta-catenin
  (Wnt) signaling in retinal vascular endothelial cells, which is required for
  developmental angiogenesis of the peripheral retina and establishment of the
  blood-retina barrier. The resulting peripheral avascular zone causes retinal
  ischemia, which drives compensatory neovascularization, exudation, hemorrhage,
  vitreoretinal traction, and tractional or exudative retinal detachment. FEVR is
  genetically heterogeneous: most cases are autosomal dominant (FZD4, LRP5,
  TSPAN12), but autosomal recessive (LRP5, TSPAN12) and X-linked recessive (NDP)
  forms occur, and KIF11 variants produce a FEVR-like retinal phenotype within a
  broader microcephaly-lymphedema-chorioretinal dysplasia spectrum. Expressivity
  is highly variable, ranging from an asymptomatic avascular periphery detectable
  only by fluorescein angiography to bilateral blindness, even within the same
  family. NDP variants additionally cause Norrie disease (a severe allelic
  disorder), and recessive LRP5 disease can be accompanied by reduced bone
  mineral density.
disease_term:
  preferred_term: familial exudative vitreoretinopathy
  term:
    id: MONDO:0019516
    label: exudative vitreoretinopathy
synonyms:
- FEVR
- Criswick-Schepens syndrome
parents:
- Ophthalmological Disease
- Retinal vascular disorder
has_subtypes:
- name: FZD4-FEVR
  display_name: FZD4-Related FEVR (EVR1, autosomal dominant)
  description: >-
    Autosomal dominant FEVR caused by heterozygous pathogenic variants in FZD4,
    encoding the frizzled-4 receptor, the obligate Norrin receptor. One of the
    most common molecularly defined forms of adFEVR. Variants impair Norrin/FZD4
    signaling and peripheral retinal vascularization.
  genes:
  - preferred_term: FZD4
    term:
      id: hgnc:4042
      label: FZD4
- name: LRP5-FEVR
  display_name: LRP5-Related FEVR (EVR4, AD or AR; with reduced bone density)
  description: >-
    FEVR caused by pathogenic variants in LRP5, encoding the Wnt co-receptor
    low-density lipoprotein receptor-related protein 5. Inherited dominantly or
    recessively; recessive disease is frequently accompanied by reduced bone
    mineral density, reflecting LRP5's role in skeletal Wnt signaling.
  genes:
  - preferred_term: LRP5
    term:
      id: hgnc:6697
      label: LRP5
- name: TSPAN12-FEVR
  display_name: TSPAN12-Related FEVR (EVR5)
  description: >-
    FEVR caused by variants in TSPAN12, encoding tetraspanin-12, an essential
    co-receptor of the Norrin/FZD4 complex that amplifies FZD4 ligand selectivity
    and signaling. Mostly autosomal dominant.
  genes:
  - preferred_term: TSPAN12
    term:
      id: hgnc:21641
      label: TSPAN12
- name: NDP-FEVR
  display_name: NDP-Related FEVR (EVR2, X-linked recessive)
  description: >-
    X-linked recessive FEVR caused by hemizygous variants in NDP, encoding the
    secreted ligand Norrin. NDP is allelic with Norrie disease; FEVR represents
    the milder end of the NDP phenotypic spectrum, affecting predominantly males.
  genes:
  - preferred_term: NDP
    term:
      id: hgnc:7678
      label: NDP
- name: KIF11-FEVR
  display_name: KIF11-Related FEVR (MLCRD/CDMMR spectrum)
  description: >-
    Autosomal dominant FEVR-like retinal phenotype caused by heterozygous variants
    in KIF11, encoding a kinesin motor. Often part of a broader syndrome
    (microcephaly, lymphedema, chorioretinal dysplasia), and FEVR cases should be
    inspected for microcephaly as a marker of KIF11-related disease.
  genes:
  - preferred_term: KIF11
    term:
      id: hgnc:6388
      label: KIF11
inheritance:
- name: Autosomal dominant inheritance
  inheritance_term:
    preferred_term: Autosomal dominant inheritance
    term:
      id: HP:0000006
      label: Autosomal dominant inheritance
  description: >-
    The most common mode of inheritance for FEVR, seen with FZD4, LRP5, TSPAN12,
    and KIF11 variants. Penetrance is reduced and expressivity is highly variable.
  evidence:
  - reference: PMID:29633588
    reference_title: "Familial Exudative Vitreoretinopathy: Pathophysiology, Diagnosis, and Management."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "these can be inherited in an autosomal dominant (most common), autosomal recessive, and X-linked recessive fashion"
    explanation: A clinical review confirms autosomal dominant inheritance is the most common FEVR mode.
  - reference: PMID:20301326
    reference_title: "Familial Exudative Vitreoretinopathy, Autosomal Dominant - RETIRED CHAPTER, FOR HISTORICAL REFERENCE ONLY."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Offspring of an affected individual are at a 50% risk of inheriting the pathogenic variant, but many individuals with adFEVR can be asymptomatic because of reduced penetrance."
    explanation: GeneReviews genetic counseling section confirms 50% recurrence risk and reduced penetrance in autosomal dominant FEVR.
- name: X-linked recessive inheritance
  inheritance_term:
    preferred_term: X-linked recessive inheritance
    term:
      id: HP:0001419
      label: X-linked recessive inheritance
  description: >-
    The NDP-related form is inherited in an X-linked recessive manner, affecting
    predominantly males; NDP is allelic with Norrie disease.
  evidence:
  - reference: PMID:29633588
    reference_title: "Familial Exudative Vitreoretinopathy: Pathophysiology, Diagnosis, and Management."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "these can be inherited in an autosomal dominant (most common), autosomal recessive, and X-linked recessive fashion"
    explanation: A clinical review confirms the X-linked recessive FEVR mode of inheritance (NDP).
- name: Autosomal recessive inheritance
  inheritance_term:
    preferred_term: Autosomal recessive inheritance
    term:
      id: HP:0000007
      label: Autosomal recessive inheritance
  description: >-
    Recessive FEVR occurs with biallelic LRP5 (and TSPAN12) variants; recessive
    LRP5 disease is associated with reduced bone mineral density.
  evidence:
  - reference: PMID:16929062
    reference_title: "Reduced bone mineral density and hyaloid vasculature remnants in a consanguineous recessive FEVR family with a mutation in LRP5."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "homozygous mutations in LRP5 have recently been reported as underlying the recessive form of this disease"
    explanation: Documents the autosomal recessive form of FEVR caused by biallelic LRP5 mutations.
genetic:
- name: FZD4 frizzled-4 receptor defect
  gene_term:
    preferred_term: FZD4
    modifier: DECREASED
    term:
      id: hgnc:4042
      label: FZD4
  relationship_type: CAUSATIVE
  notes: >-
    FZD4 encodes frizzled-4, the obligate Norrin receptor. Loss-of-function
    variants in humans and Fz4 knockout mice produce similar incomplete retinal
    vascularization, establishing Norrin and FZD4 as a high-affinity
    ligand-receptor pair controlling retinal angiogenesis.
  evidence:
  - reference: PMID:15035989
    reference_title: "Vascular development in the retina and inner ear: control by Norrin and Frizzled-4, a high-affinity ligand-receptor pair."
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: "One form of \nFEVR is caused by defects in Frizzled-4 (Fz4), a presumptive Wnt receptor."
    explanation: Identifies FZD4 (Fz4) defects as a cause of FEVR.
- name: NDP Norrin ligand defect
  gene_term:
    preferred_term: NDP
    modifier: DECREASED
    term:
      id: hgnc:7678
      label: NDP
  relationship_type: CAUSATIVE
  notes: >-
    NDP encodes Norrin, the secreted cysteine-knot ligand for FZD4. NDP variants
    cause X-linked FEVR and the allelic, more severe Norrie disease.
  evidence:
  - reference: PMID:20340138
    reference_title: "Overview of the mutation spectrum in familial exudative vitreoretinopathy and Norrie disease with identification of 21 novel variants in FZD4, LRP5, and NDP."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "mutations in the gene encoding NDP, a ligand \nfor these Wnt receptors, cause Norrie disease and FEVR"
    explanation: Confirms NDP (Norrin) ligand mutations cause both FEVR and the allelic Norrie disease.
- name: LRP5 Wnt co-receptor defect
  gene_term:
    preferred_term: LRP5
    modifier: DECREASED
    term:
      id: hgnc:6697
      label: LRP5
  relationship_type: CAUSATIVE
  notes: >-
    LRP5 encodes a Wnt/Norrin co-receptor. Pathogenic variants cause FEVR;
    recessive disease additionally produces reduced bone mineral density,
    reflecting LRP5's dual role in retinal vascular and skeletal Wnt signaling.
  evidence:
  - reference: PMID:16929062
    reference_title: "Reduced bone mineral density and hyaloid vasculature remnants in a consanguineous recessive FEVR family with a mutation in LRP5."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "A homozygous LRP5 missense mutation, G550R, was \nidentified in all affected individuals"
    explanation: Identifies a homozygous LRP5 mutation segregating with recessive FEVR and reduced bone density.
- name: TSPAN12 co-receptor defect
  gene_term:
    preferred_term: TSPAN12
    modifier: DECREASED
    term:
      id: hgnc:21641
      label: TSPAN12
  relationship_type: CAUSATIVE
  notes: >-
    TSPAN12 encodes tetraspanin-12, an essential component of the Norrin receptor
    complex. FEVR-linked TSPAN12 mutations prevent its incorporation into the
    Norrin/FZD4 complex, reducing signaling amplitude.
  evidence:
  - reference: PMID:28658627
    reference_title: "TSPAN12 Is a Norrin Co-receptor that Amplifies Frizzled4 Ligand Selectivity and Signaling."
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: "FEVR-linked mutations in TSPAN12 \nprevent the incorporation of TSPAN12 into the NDP receptor complex."
    explanation: Mechanistic study shows FEVR TSPAN12 mutations disrupt assembly of the Norrin receptor complex.
- name: KIF11 kinesin motor defect
  gene_term:
    preferred_term: KIF11
    modifier: DECREASED
    term:
      id: hgnc:6388
      label: KIF11
  relationship_type: CAUSATIVE
  notes: >-
    KIF11 encodes a kinesin motor. Heterozygous variants cause a FEVR-like retinal
    phenotype, frequently within the microcephaly-lymphedema-chorioretinal
    dysplasia spectrum, implicating KIF11 in retinal vascular development.
  evidence:
  - reference: PMID:25124931
    reference_title: "Phenotypic overlap between familial exudative vitreoretinopathy and microcephaly, lymphedema, and chorioretinal dysplasia caused by KIF11 mutations."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The KIF11 gene \nlikely plays a role in retinal vascular development and mutations in this gene \ncan lead to clinical overlap with FEVR."
    explanation: Identifies KIF11 mutations as a cause of a FEVR-overlapping retinal phenotype.
- name: ZNF408 zinc finger protein defect
  gene_term:
    preferred_term: ZNF408
    modifier: DECREASED
    term:
      id: hgnc:20041
      label: ZNF408
  relationship_type: CAUSATIVE
  notes: >-
    ZNF408 encodes a zinc finger protein; pathogenic variants cause FEVR with
    typically mild clinical phenotypes. ZNF408 variants may act partly outside the
    canonical Norrin/Wnt signaling pathway. In the largest infant cohort, patients
    with ZNF408 mutations presented the mildest clinical phenotypes compared to
    other FEVR genotypes.
  evidence:
  - reference: DOI:10.3390/cells12212579
    reference_title: "Mechanisms Underlying Rare Inherited Pediatric Retinal Vascular Diseases: FEVR, Norrie Disease, Persistent Fetal Vascular Syndrome"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "discovery of pathological variants in additional genes such as CTNNB1, KIF11, and ZNF408, some of which operate outside of the Norrin Wnt-signaling pathway"
    explanation: Identifies ZNF408 as a FEVR causal gene; some variants operate outside the canonical Norrin/Wnt pathway.
- name: CTNNB1 beta-catenin defect
  gene_term:
    preferred_term: CTNNB1
    modifier: DECREASED
    term:
      id: hgnc:2514
      label: CTNNB1
  relationship_type: CAUSATIVE
  notes: >-
    CTNNB1 encodes beta-catenin, the intracellular effector of canonical Wnt
    signaling. Pathogenic variants directly disrupt Wnt/beta-catenin transcriptional
    output in retinal endothelial cells, implicating the core effector arm of the
    Norrin/Wnt pathway in FEVR pathogenesis.
  evidence:
  - reference: DOI:10.3390/cells12212579
    reference_title: "Mechanisms Underlying Rare Inherited Pediatric Retinal Vascular Diseases: FEVR, Norrie Disease, Persistent Fetal Vascular Syndrome"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "discovery of pathological variants in additional genes such as CTNNB1, KIF11, and ZNF408, some of which operate outside of the Norrin Wnt-signaling pathway"
    explanation: Identifies CTNNB1 as a FEVR causal gene; beta-catenin is the canonical intracellular effector of Wnt signaling.
pathophysiology:
- name: Impaired Norrin/beta-catenin signaling in retinal endothelium
  description: >-
    The core defect of FEVR. Norrin (NDP) is a secreted ligand that binds the
    frizzled-4 (FZD4) receptor together with the co-receptor LRP5 and the
    accessory tetraspanin TSPAN12, activating canonical (beta-catenin-dependent)
    Wnt signaling specifically in retinal vascular endothelial cells. Loss-of-function
    in any of these components reduces beta-catenin signaling output. Disruption of
    Tspan12, Ndp, Fzd4, or Lrp5 in mice produces similar ocular phenotypes,
    indicating a shared signaling pathway.
  gene:
    preferred_term: FZD4
    modifier: DECREASED
    term:
      id: hgnc:4042
      label: FZD4
  cell_types:
  - preferred_term: retinal blood vessel endothelial cell
    term:
      id: CL:0002585
      label: retinal blood vessel endothelial cell
  biological_processes:
  - preferred_term: Norrin signaling pathway
    modifier: DECREASED
    term:
      id: GO:0110135
      label: Norrin signaling pathway
  - preferred_term: canonical Wnt signaling pathway
    modifier: DECREASED
    term:
      id: GO:0060070
      label: canonical Wnt signaling pathway
  evidence:
  - reference: PMID:28658627
    reference_title: "TSPAN12 Is a Norrin Co-receptor that Amplifies Frizzled4 Ligand Selectivity and Signaling."
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: "Gene disruptions of Tspan12 (Junge et al., 2009), Ndp (Luhmann et al., 2005), Fzd4 (Xu et al., 2004; Ye et al., 2009), and Lrp5 (Xia et al., 2008) all result in similar ocular phenotypes in mice, characterized by defects in intraretinal capillary development and dysregulation of the blood-retina barrier."
    explanation: Shows the convergent ocular phenotype across all four core Norrin-pathway genes, defining the shared mechanism.
  - reference: PMID:28658627
    reference_title: "TSPAN12 Is a Norrin Co-receptor that Amplifies Frizzled4 Ligand Selectivity and Signaling."
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: "TSPAN12 is \nan essential component of the NDP receptor complex and interacts with FZD4 and \nNDP via its extracellular loops, consistent with an action as co-receptor that \nenhances FZD4 ligand selectivity for NDP."
    explanation: Establishes the molecular assembly of the Norrin/FZD4/TSPAN12 receptor complex underlying the pathway.
  downstream:
  - target: Incomplete peripheral retinal vascularization
    causal_link_type: DIRECT
    description: >-
      Reduced Norrin/beta-catenin signaling impairs developmental angiogenesis of
      the peripheral retina, leaving an avascular peripheral zone.
    evidence:
    - reference: PMID:15035989
      reference_title: "Vascular development in the retina and inner ear: control by Norrin and Frizzled-4, a high-affinity ligand-receptor pair."
      supports: SUPPORT
      evidence_source: MODEL_ORGANISM
      snippet: "Incomplete retinal vascularization occurs in both Norrie disease and familial \nexudative vitreoretinopathy (FEVR)."
      explanation: Directly links the Norrin/FZD4 pathway defect to incomplete retinal vascularization.
  - target: Inner Blood-Retinal Barrier Dysfunction
    causal_link_type: DIRECT
    description: >-
      Reduced Norrin/beta-catenin signaling also impairs formation and maintenance
      of the inner blood-retinal barrier (iBRB) in retinal endothelial cells,
      contributing to vascular permeability and retinal exudation.
    evidence:
    - reference: DOI:10.3390/cells12212579
      reference_title: "Mechanisms Underlying Rare Inherited Pediatric Retinal Vascular Diseases: FEVR, Norrie Disease, Persistent Fetal Vascular Syndrome"
      supports: SUPPORT
      evidence_source: OTHER
      snippet: "irregular retinal vascular development and/or aberrant inner blood-retinal-barrier (iBRB) function"
      explanation: Establishes iBRB dysfunction as a pathophysiological element of FEVR driven by Norrin/Wnt signaling defects.
- name: Incomplete peripheral retinal vascularization
  description: >-
    The hallmark structural lesion of FEVR: failure of the retinal vasculature to
    grow into the peripheral retina, producing a bilateral peripheral avascular
    zone. This avascularity is probably present from birth and is detectable by
    fundus fluorescein angiography even in asymptomatic individuals.
  cell_types:
  - preferred_term: retinal blood vessel endothelial cell
    term:
      id: CL:0002585
      label: retinal blood vessel endothelial cell
  biological_processes:
  - preferred_term: retina vasculature development in camera-type eye
    modifier: DECREASED
    term:
      id: GO:0061298
      label: retina vasculature development in camera-type eye
  - preferred_term: establishment of blood-retinal barrier
    modifier: DECREASED
    term:
      id: GO:1990963
      label: establishment of blood-retinal barrier
  evidence:
  - reference: PMID:29633588
    reference_title: "Familial Exudative Vitreoretinopathy: Pathophysiology, Diagnosis, and Management."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The principal feature \nof the disease is an avascular peripheral retina."
    explanation: Identifies the peripheral avascular retina as the principal structural feature of FEVR.
  downstream:
  - target: Peripheral retinal ischemia and neovascular response
    causal_link_type: DIRECT
    description: >-
      The non-perfused peripheral retina becomes ischemic, generating a
      pro-angiogenic drive (e.g., VEGF) that triggers abnormal neovascularization.
    evidence:
    - reference: PMID:29633588
      reference_title: "Familial Exudative Vitreoretinopathy: Pathophysiology, Diagnosis, and Management."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "This in turn can cause further \npathological changes including neovascularization, exudation, hemorrhage, and \nretinal detachment."
      explanation: Links the avascular periphery to the downstream neovascular and exudative complications.
  - target: Peripheral retinal avascularization
    causal_link_type: DIRECT
    description: The same developmental vascularization failure is recorded clinically as peripheral retinal avascularization.
    evidence:
    - reference: ORPHA:891
      reference_title: "Familial exudative vitreoretinopathy (Orphanet structured-database record)"
      supports: SUPPORT
      evidence_source: OTHER
      snippet: "HP:0007685 | Peripheral retinal avascularization | Very frequent (99-80%)"
      explanation: Orphanet records peripheral retinal avascularization as a very frequent FEVR phenotype.
- name: Peripheral retinal ischemia and neovascular response
  description: >-
    Ischemia of the peripheral avascular retina drives pathological
    neovascularization, with exudation and hemorrhage. These vascular sequelae are
    the proximate cause of the symptomatic complications of FEVR.
  cell_types:
  - preferred_term: capillary endothelial cell
    term:
      id: CL:0002144
      label: capillary endothelial cell
  biological_processes:
  - preferred_term: angiogenesis
    modifier: INCREASED
    term:
      id: GO:0001525
      label: angiogenesis
  evidence:
  - reference: PMID:29633588
    reference_title: "Familial Exudative Vitreoretinopathy: Pathophysiology, Diagnosis, and Management."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "This in turn can cause further \npathological changes including neovascularization, exudation, hemorrhage, and \nretinal detachment."
    explanation: Documents neovascularization, exudation, and hemorrhage as ischemia-driven sequelae.
  downstream:
  - target: Vitreoretinal traction and retinal detachment
    causal_link_type: DIRECT
    description: >-
      Fibrovascular proliferation and contraction exert tractional forces on the
      retina, and exudation accumulates, producing tractional, rhegmatogenous, or
      exudative retinal detachment and ultimately vision loss.
    evidence:
    - reference: PMID:20340138
      reference_title: "Overview of the mutation spectrum in familial exudative vitreoretinopathy and Norrie disease with identification of 21 novel variants in FZD4, LRP5, and NDP."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "abnormal \nvascularization of the peripheral retina and formation of fibrovascular masses \nin the eye that can lead to blindness"
      explanation: Links fibrovascular proliferation to the tractional sequelae and blindness.
- name: Vitreoretinal traction and retinal detachment
  description: >-
    Terminal convergence of FEVR: fibrovascular traction and exudation cause
    macular dragging, falciform retinal folds, and partial or total retinal
    detachment, leading to severe visual impairment or blindness. Expressivity is
    highly variable.
  cell_types:
  - preferred_term: capillary endothelial cell
    term:
      id: CL:0002144
      label: capillary endothelial cell
  biological_processes:
  - preferred_term: retinal blood vessel morphogenesis
    modifier: DYSREGULATED
    term:
      id: GO:0061304
      label: retinal blood vessel morphogenesis
  evidence:
  - reference: PMID:25124931
    reference_title: "Phenotypic overlap between familial exudative vitreoretinopathy and microcephaly, lymphedema, and chorioretinal dysplasia caused by KIF11 mutations."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "macular dragging, partial retinal detachment, falciform folds, or total retinal \ndetachment"
    explanation: Catalogs the tractional retinal sequelae that define advanced FEVR.
  downstream:
  - target: Tractional retinal detachment
    causal_link_type: DIRECT
    description: Fibrovascular traction is the proximate mechanism for tractional retinal detachment.
  - target: Reduced visual acuity
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    intermediate_mechanisms:
    - tractional retinal detachment
    - macular exudation
    description: Retinal detachment, exudation, and macular involvement reduce visual acuity in symptomatic FEVR.
- name: Inner Blood-Retinal Barrier Dysfunction
  description: >-
    Norrin/Wnt signaling in retinal endothelial cells governs not only developmental
    angiogenesis but also formation and maintenance of the inner blood-retinal
    barrier (iBRB). Loss-of-function in FZD4, LRP5, NDP, or TSPAN12 impairs
    iBRB integrity, producing aberrant vascular permeability that contributes to
    retinal exudation independently of ischemia-driven neovascularization. FEVR,
    Norrie disease, and persistent fetal vascular syndrome share this iBRB
    dysfunction as a unifying pathophysiological element.
  cell_types:
  - preferred_term: retinal blood vessel endothelial cell
    term:
      id: CL:0002585
      label: retinal blood vessel endothelial cell
  biological_processes:
  - preferred_term: establishment of blood-retinal barrier
    modifier: DECREASED
    term:
      id: GO:1990963
      label: establishment of blood-retinal barrier
  evidence:
  - reference: DOI:10.3390/cells12212579
    reference_title: "Mechanisms Underlying Rare Inherited Pediatric Retinal Vascular Diseases: FEVR, Norrie Disease, Persistent Fetal Vascular Syndrome"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "unified by abnormal retinal endothelial cell function, and subsequent irregular retinal vascular development and/or aberrant inner blood-retinal-barrier (iBRB) function"
    explanation: >-
      Establishes iBRB dysfunction as a distinct pathophysiological element shared
      across FEVR-related disorders, driven by abnormal Norrin/Wnt signaling in
      retinal endothelial cells.
phenotypes:
- category: Ophthalmic
  name: Exudative vitreoretinopathy
  description: >-
    The defining clinical feature: abnormal peripheral retinal vascular
    development with exudation, the eponymous lesion of the disease.
  phenotype_term:
    preferred_term: Exudative vitreoretinopathy
    term:
      id: HP:0030490
      label: Exudative vitreoretinopathy
  evidence:
  - reference: PMID:29633588
    reference_title: "Familial Exudative Vitreoretinopathy: Pathophysiology, Diagnosis, and Management."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Familial exudative vitreoretinopathy (FEVR) is a heritable vitreoretinopathy \ncharacterized by anomalous retinal vascular development."
    explanation: Defines FEVR as an exudative vitreoretinopathy with anomalous retinal vascular development.
- category: Ophthalmic
  name: Peripheral retinal neovascularization
  description: >-
    Abnormal new vessel growth at the junction of vascular and avascular retina,
    driven by peripheral ischemia.
  phenotype_term:
    preferred_term: Peripheral retinal neovascularization
    term:
      id: HP:0030667
      label: Peripheral retinal neovascularization
  evidence:
  - reference: PMID:29633588
    reference_title: "Familial Exudative Vitreoretinopathy: Pathophysiology, Diagnosis, and Management."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "This in turn can cause further \npathological changes including neovascularization, exudation, hemorrhage, and \nretinal detachment."
    explanation: Documents neovascularization as a complication of the avascular periphery.
- category: Ophthalmic
  name: Retinal exudate
  description: >-
    Lipid and protein exudation into the retina, characteristic of the exudative
    phase of the disease.
  phenotype_term:
    preferred_term: Retinal exudate
    term:
      id: HP:0001147
      label: Retinal exudate
  evidence:
  - reference: PMID:29633588
    reference_title: "Familial Exudative Vitreoretinopathy: Pathophysiology, Diagnosis, and Management."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "This in turn can cause further \npathological changes including neovascularization, exudation, hemorrhage, and \nretinal detachment."
    explanation: Lists exudation among the pathological changes of FEVR.
- category: Ophthalmic
  name: Falciform retinal fold
  description: >-
    A sickle-shaped fold of retina dragged toward the temporal periphery by
    fibrovascular traction, a classic FEVR sign.
  phenotype_term:
    preferred_term: Falciform retinal fold
    term:
      id: HP:0001493
      label: Falciform retinal fold
  evidence:
  - reference: PMID:25124931
    reference_title: "Phenotypic overlap between familial exudative vitreoretinopathy and microcephaly, lymphedema, and chorioretinal dysplasia caused by KIF11 mutations."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "macular dragging, partial retinal detachment, falciform folds, or total retinal \ndetachment"
    explanation: Falciform folds are documented among the tractional retinal manifestations.
- category: Ophthalmic
  name: Retinal detachment
  description: >-
    Tractional, rhegmatogenous, or exudative retinal detachment, the major
    sight-threatening complication of FEVR.
  phenotype_term:
    preferred_term: Retinal detachment
    term:
      id: HP:0000541
      label: Retinal detachment
    clinical_course: PROGRESSIVE
  evidence:
  - reference: PMID:25124931
    reference_title: "Phenotypic overlap between familial exudative vitreoretinopathy and microcephaly, lymphedema, and chorioretinal dysplasia caused by KIF11 mutations."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Retinal detachment with avascularity of the peripheral retina, \ntypically associated with familial exudative vitreoretinopathy (FEVR)"
    explanation: Associates retinal detachment with peripheral avascularity in FEVR.
- category: Ophthalmic
  name: Peripheral retinal avascularization
  description: >-
    Failure of the retinal vasculature to reach the periphery, leaving the
    avascular peripheral retina that drives later ischemic and exudative changes.
  frequency: VERY_FREQUENT
  phenotype_term:
    preferred_term: Peripheral retinal avascularization
    term:
      id: HP:0007685
      label: Avascular peripheral retina
  evidence:
  - reference: PMID:20301326
    reference_title: "Familial Exudative Vitreoretinopathy, Autosomal Dominant - RETIRED CHAPTER, FOR HISTORICAL REFERENCE ONLY."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "bilateral peripheral retinal avascularity, seen temporally, by indirect ophthalmoscope and scleral indentation, or by fundus fluorescein angiography"
    explanation: GeneReviews defines bilateral peripheral retinal avascularity as the diagnostic hallmark of FEVR.
  - reference: ORPHA:891
    reference_title: "Familial exudative vitreoretinopathy (Orphanet structured-database record)"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0007685 | Peripheral retinal avascularization | Very frequent (99-80%)"
    explanation: Orphanet records peripheral retinal avascularization as a very frequent FEVR phenotype.
- category: Ophthalmic
  name: Vitreoretinopathy
  description: >-
    Vitreoretinal disease is the obligate clinical category for FEVR and
    encompasses the abnormal retinal vascularization, exudation, and tractional sequelae.
  frequency: OBLIGATE
  phenotype_term:
    preferred_term: Vitreoretinopathy
    term:
      id: HP:0007773
      label: Vitreoretinopathy
  evidence:
  - reference: ORPHA:891
    reference_title: "Familial exudative vitreoretinopathy (Orphanet structured-database record)"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0007773 | Vitreoretinopathy | Obligate (100%)"
    explanation: Orphanet records vitreoretinopathy as an obligate FEVR phenotype.
- category: Ophthalmic
  name: Reduced visual acuity
  description: Reduced acuity from macular exudation, traction, or retinal detachment.
  frequency: FREQUENT
  phenotype_term:
    preferred_term: Reduced visual acuity
    term:
      id: HP:0007663
      label: Reduced visual acuity
  evidence:
  - reference: ORPHA:891
    reference_title: "Familial exudative vitreoretinopathy (Orphanet structured-database record)"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0007663 | Reduced visual acuity | Frequent (79-30%)"
    explanation: Orphanet records reduced visual acuity as a frequent FEVR phenotype.
- category: Ophthalmic
  name: Tractional retinal detachment
  description: Detachment caused by fibrovascular traction on the retina in advanced FEVR.
  frequency: FREQUENT
  phenotype_term:
    preferred_term: Tractional retinal detachment
    term:
      id: HP:0007917
      label: Tractional retinal detachment
  evidence:
  - reference: ORPHA:891
    reference_title: "Familial exudative vitreoretinopathy (Orphanet structured-database record)"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0007917 | Tractional retinal detachment | Frequent (79-30%)"
    explanation: Orphanet records tractional retinal detachment as a frequent FEVR phenotype.
- category: Ophthalmic
  name: Macular exudate
  description: Exudative macular involvement that contributes to reduced central visual function.
  frequency: OCCASIONAL
  phenotype_term:
    preferred_term: Macular exudate
    term:
      id: HP:0030496
      label: Macular exudate
  evidence:
  - reference: ORPHA:891
    reference_title: "Familial exudative vitreoretinopathy (Orphanet structured-database record)"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0030496 | Macular exudate | Occasional (29-5%)"
    explanation: Orphanet records macular exudate as an occasional FEVR phenotype.
- category: Ophthalmic
  name: Remnants of the hyaloid vascular system
  subtype: LRP5-FEVR
  description: >-
    Persistent hyaloid vasculature remnants, reported as a feature of recessive
    LRP5-related FEVR.
  phenotype_term:
    preferred_term: Remnants of the hyaloid vascular system
    term:
      id: HP:0007968
      label: Remnants of the hyaloid vascular system
  evidence:
  - reference: PMID:16929062
    reference_title: "Reduced bone mineral density and hyaloid vasculature remnants in a consanguineous recessive FEVR family with a mutation in LRP5."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Reduced BMD, hyaloid \nvasculature remnants, and nystagmus were features of the phenotype."
    explanation: Documents hyaloid vasculature remnants in a recessive LRP5 FEVR family.
- category: Musculoskeletal
  name: Reduced bone mineral density
  subtype: LRP5-FEVR
  description: >-
    Reduced bone mineral density accompanies recessive LRP5-related FEVR,
    reflecting LRP5's role in skeletal Wnt signaling; its presence suggests an
    underlying LRP5 mutation.
  phenotype_term:
    preferred_term: Reduced bone mineral density
    term:
      id: HP:0004349
      label: Reduced bone mineral density
  evidence:
  - reference: PMID:16929062
    reference_title: "Reduced bone mineral density and hyaloid vasculature remnants in a consanguineous recessive FEVR family with a mutation in LRP5."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Assessment of a patient with a provisional \ndiagnosis of FEVR should therefore include investigation of BMD, with reduced \nlevels suggestive of an underlying LRP5 mutation."
    explanation: Establishes reduced bone mineral density as a feature of LRP5-related recessive FEVR.
- category: Neurologic
  name: Nystagmus
  subtype: LRP5-FEVR
  description: >-
    Nystagmus was reported among the extraocular features of recessive
    LRP5-related FEVR, alongside reduced bone mineral density and hyaloid
    vasculature remnants.
  phenotype_term:
    preferred_term: Nystagmus
    term:
      id: HP:0000639
      label: Nystagmus
  evidence:
  - reference: PMID:16929062
    reference_title: "Reduced bone mineral density and hyaloid vasculature remnants in a consanguineous recessive FEVR family with a mutation in LRP5."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "vasculature remnants, and nystagmus were features of the phenotype"
    explanation: Reports nystagmus as a feature of the recessive LRP5-related FEVR phenotype.
- category: Neurologic
  name: Microcephaly
  subtype: KIF11-FEVR
  description: >-
    Microcephaly is the key extraocular marker of KIF11-related disease; FEVR
    cases should be inspected for microcephaly to identify KIF11-related disease.
  phenotype_term:
    preferred_term: Microcephaly
    term:
      id: HP:0000252
      label: Microcephaly
  evidence:
  - reference: PMID:25124931
    reference_title: "Phenotypic overlap between familial exudative vitreoretinopathy and microcephaly, lymphedema, and chorioretinal dysplasia caused by KIF11 mutations."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Cases of FEVR should be carefully \ninspected for the presence of microcephaly as a marker for KIF11-related disease"
    explanation: Identifies microcephaly as a marker distinguishing KIF11-related FEVR.
- category: Ophthalmic
  name: Myopia
  subtype: FZD4-FEVR
  description: >-
    Myopia is markedly overrepresented in FZD4-variant-positive individuals,
    occurring in 62% of study eyes in a Finnish cohort. Whether this represents a
    direct consequence of altered retinal vascular development or a secondary
    effect of the structural changes in FEVR is not yet established.
  frequency: FREQUENT
  phenotype_term:
    preferred_term: Myopia
    term:
      id: HP:0000545
      label: Myopia
  evidence:
  - reference: DOI:10.1111/aos.16701
    reference_title: "Clinical and genetic characteristics and natural history of Finnish families with familial exudative vitreoretinopathy due to pathogenic FZD4 variants"
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Myopia seemed to be overly common in FZD4‐variant‐positive individuals."
    explanation: >-
      Finnish natural history study documents myopia as a frequent finding in
      FZD4-variant-positive individuals (62% of study eyes).
- category: Ophthalmic
  name: Strabismus
  description: >-
    Strabismus is a common presenting feature in infant FEVR, occurring in 20%
    of cases at first clinical visit, likely reflecting disrupted visual
    input from asymmetric retinal disease or retinal detachment.
  frequency: OCCASIONAL
  phenotype_term:
    preferred_term: Strabismus
    term:
      id: HP:0000486
      label: Strabismus
  evidence:
  - reference: DOI:10.1186/s12886-022-02522-8
    reference_title: "Long-term clinical prognosis of 335 infant single-gene positive FEVR cases"
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "20% (n = 67) was diagnosed of strabismus at first visit"
    explanation: >-
      Among 335 single-gene positive infant FEVR cases, 20% presented with
      strabismus at first clinical visit.
- category: Ophthalmic
  name: Vitreous hemorrhage
  description: >-
    Vitreous hemorrhage is an occasional complication of FEVR, occurring from
    neovascular tufts at the vascular-avascular junction or from tractional
    retinal tears.
  frequency: OCCASIONAL
  phenotype_term:
    preferred_term: Vitreous hemorrhage
    term:
      id: HP:0007902
      label: Vitreous hemorrhage
  evidence:
  - reference: ORPHA:891
    reference_title: "Familial exudative vitreoretinopathy (Orphanet structured-database record)"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0007902 | Vitreous hemorrhage | Occasional (29-5%)"
    explanation: Orphanet records vitreous hemorrhage as an occasional FEVR phenotype.
- category: Ophthalmic
  name: Abnormality of the optic disc
  description: >-
    Optic disc abnormalities including dragging of the optic disc from fibrovascular
    traction, a recognized feature of advanced FEVR.
  frequency: FREQUENT
  phenotype_term:
    preferred_term: Abnormality of the optic disc
    term:
      id: HP:0012795
      label: Abnormal optic disc morphology
  evidence:
  - reference: ORPHA:891
    reference_title: "Familial exudative vitreoretinopathy (Orphanet structured-database record)"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0012795 | Abnormality of the optic disc | Frequent (79-30%)"
    explanation: Orphanet records abnormality of the optic disc as a frequent FEVR phenotype.
- category: Ophthalmic
  name: Retinal neovascularization
  description: >-
    Abnormal new vessel growth arising in response to peripheral retinal ischemia;
    an intermediate and defining feature of the FEVR pathophysiology chain.
  frequency: FREQUENT
  phenotype_term:
    preferred_term: Retinal neovascularization
    term:
      id: HP:0030666
      label: Retinal neovascularization
  evidence:
  - reference: ORPHA:891
    reference_title: "Familial exudative vitreoretinopathy (Orphanet structured-database record)"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0030666 | Retinal neovascularization | Frequent (79-30%)"
    explanation: Orphanet records retinal neovascularization as a frequent FEVR phenotype.
- category: Ophthalmic
  name: Subretinal fluid
  description: >-
    Fluid accumulation beneath the retina from exudative retinal detachment or
    active subretinal exudation in FEVR.
  frequency: FREQUENT
  phenotype_term:
    preferred_term: Subretinal fluid
    term:
      id: HP:0031526
      label: Subretinal fluid
  evidence:
  - reference: ORPHA:891
    reference_title: "Familial exudative vitreoretinopathy (Orphanet structured-database record)"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HP:0031526 | Subretinal fluid | Frequent (79-30%)"
    explanation: Orphanet records subretinal fluid as a frequent FEVR phenotype.
progression:
- phase: Stage 1 — Peripheral avascular zone
  notes: >-
    The earliest and mildest detectable finding: a peripheral avascular zone with
    or without abnormal vascularization at the avascular-vascular junction.
    Detectable by fundus fluorescein angiography even in asymptomatic individuals.
    Many variant-positive individuals remain at Stage 1 throughout life; it is
    the most common stage in FZD4-FEVR (40% of eyes in a Finnish cohort).
- phase: Stage 2 — Extraretinal neovascularization
  notes: >-
    Stage 2a: flat extraretinal neovascularization at the junction of vascular
    and avascular retina without subretinal or intravitreal exudate. Stage 2b:
    extraretinal neovascularization with exudate. Ischemia-driven neovascular
    tufts are present; laser photocoagulation or cryotherapy is indicated to
    prevent progression. Intravitreal injection is used for Stages 1-3 with
    vision maintained above 20/67 at last follow-up.
- phase: Stage 3 — Extramacular retinal detachment
  notes: >-
    Fibrovascular traction or exudative retinal detachment that does not involve
    the macula. Vitreoretinal surgery may be required. Visual prognosis is still
    relatively good if the macula is spared.
- phase: Stage 4 — Subtotal retinal detachment involving the macula
  notes: >-
    Partial retinal detachment extending to or involving the macula, causing
    significant visual impairment. Vitrectomy (with or without lensectomy) is
    the primary intervention; lens-sparing vitrectomy preserves lens transparency
    in approximately 79% of cases (11/14 eyes).
- phase: Stage 5 — Total retinal detachment
  notes: >-
    Complete retinal detachment with a funnel configuration, the most severe
    outcome. In a large infant cohort, 69% of Stage 5 surgeries occurred in the
    first year of life. After 2-10 years of follow-up, approximately 38% of
    post-surgical cases showed favorable retinal unfolding. At last follow-up,
    20% of all patients retained vision above 20/200. NDP mutations are associated
    with the most severe phenotypes; ZNF408 mutations with the mildest.
treatments:
- name: Laser Photocoagulation
  description: >-
    Argon laser photocoagulation of the avascular peripheral retina to induce
    regression of ischemia-driven new vessel growth and reduce neovascular and
    exudative sequelae.
  treatment_term:
    preferred_term: laser photocoagulation
    term:
      id: NCIT:C217424
      label: Laser Photocoagulation
  evidence:
  - reference: PMID:29633588
    reference_title: "Familial Exudative Vitreoretinopathy: Pathophysiology, Diagnosis, and Management."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The current treatment paradigm involves laser photocoagulation \nof the avascular peripheral retina for neovascular sequelae"
    explanation: Identifies laser photocoagulation of the avascular periphery as the standard treatment for neovascular FEVR.
- name: Peripheral Retinal Cryotherapy
  description: >-
    Cryotherapy of the avascular peripheral retina to induce regression of
    neovascularization and to stabilize areas of exudate or retinal holes.
  treatment_term:
    preferred_term: cryosurgery
    term:
      id: NCIT:C15215
      label: Cryosurgery
  evidence:
  - reference: PMID:20301326
    reference_title: "Familial Exudative Vitreoretinopathy, Autosomal Dominant - RETIRED CHAPTER, FOR HISTORICAL REFERENCE ONLY."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Prophylactic cryotherapy or argon laser \nphotocoagulation to induce regression of new vessel growth caused by ischemia"
    explanation: GeneReviews documents prophylactic cryotherapy to induce regression of ischemic neovascularization.
- name: Vitreoretinal Surgery
  description: >-
    Vitrectomy and related vitreoretinal surgery to repair tractional or
    rhegmatogenous retinal detachment in progressive FEVR.
  treatment_term:
    preferred_term: vitrectomy
    term:
      id: NCIT:C50837
      label: Vitrectomy
  evidence:
  - reference: PMID:29633588
    reference_title: "Familial Exudative Vitreoretinopathy: Pathophysiology, Diagnosis, and Management."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "vitreoretinal \nsurgery for progressive retinal detachment"
    explanation: Documents vitreoretinal surgery for progressive retinal detachment in FEVR.
- name: Anti-VEGF Therapy
  description: >-
    Intravitreal anti-VEGF agents (e.g., bevacizumab) have been used as an adjunct
    to suppress ischemia-driven neovascularization and exudation in FEVR.
  therapeutic_modality: MONOCLONAL_ANTIBODY
  treatment_term:
    preferred_term: Pharmacotherapy
    term:
      id: NCIT:C15986
      label: Pharmacotherapy
    therapeutic_agent:
    - preferred_term: bevacizumab
      term:
        id: NCIT:C2039
        label: Bevacizumab
  notes: >-
    Intravitreal anti-VEGF (e.g., bevacizumab) is used clinically as an adjunct
    for FEVR-associated neovascularization/exudation. No FEVR-specific quotable
    snippet was available in the cited references (the only "anti-VEGF" mention
    in PMID:30513356 is in its age-related macular degeneration section, not the
    FEVR discussion), so this established adjunctive use is recorded in notes
    rather than attached to a mismatched evidence item.
clinical_trials:
- name: NCT05107921
  phase: PHASE_II
  status: UNKNOWN
  description: >-
    Phase II trial evaluating the efficacy and safety of bromfenac sodium hydrate
    eye drops in children with FEVR receiving diode laser photocoagulation.
    Bromfenac is an NSAID (COX inhibitor) used topically to suppress
    inflammation and exudation following retinal laser treatment.
  target_phenotypes:
  - preferred_term: Peripheral retinal neovascularization
    term:
      id: HP:0030667
      label: Peripheral retinal neovascularization
  evidence:
  - reference: clinicaltrials:NCT05107921
    reference_title: "Efficacy of Bromfenac Sodium Hydrate Eye Drops in Children With Familial Exudative Vitreoretinopathy After Diode Laser Photocoagulation"
    supports: SUPPORT
    snippet: "This study aims to investigate the efficacy and safety of bromfenac sodium hydrate eye drops in patients with familial exudative vitreoretinopathy receiving diode laser photocoagulation."
    explanation: >-
      Phase II trial assessing bromfenac as an adjunctive NSAID therapy in
      pediatric FEVR patients undergoing diode laser photocoagulation.
references:
- reference: PMID:20301326
  title: "Familial Exudative Vitreoretinopathy, Autosomal Dominant - RETIRED CHAPTER, FOR HISTORICAL REFERENCE ONLY."
  tags:
  - GeneReviews
- reference: DOI:10.3390/cells12212579
  title: "Mechanisms Underlying Rare Inherited Pediatric Retinal Vascular Diseases: FEVR, Norrie Disease, Persistent Fetal Vascular Syndrome"
- reference: DOI:10.1111/aos.16701
  title: "Clinical and genetic characteristics and natural history of Finnish families with familial exudative vitreoretinopathy due to pathogenic FZD4 variants"
- reference: DOI:10.1186/s12886-022-02522-8
  title: "Long-term clinical prognosis of 335 infant single-gene positive FEVR cases"
- reference: clinicaltrials:NCT05107921
  title: "Efficacy of Bromfenac Sodium Hydrate Eye Drops in Children With Familial Exudative Vitreoretinopathy After Diode Laser Photocoagulation"
- reference: PMID:15035989
  title: "Vascular development in the retina and inner ear: control by Norrin and Frizzled-4, a high-affinity ligand-receptor pair."
- reference: PMID:16929062
  title: "Reduced bone mineral density and hyaloid vasculature remnants in a consanguineous recessive FEVR family with a mutation in LRP5."
- reference: PMID:20340138
  title: "Overview of the mutation spectrum in familial exudative vitreoretinopathy and Norrie disease with identification of 21 novel variants in FZD4, LRP5, and NDP."
- reference: PMID:25124931
  title: "Phenotypic overlap between familial exudative vitreoretinopathy and microcephaly, lymphedema, and chorioretinal dysplasia caused by KIF11 mutations."
- reference: PMID:28658627
  title: "TSPAN12 Is a Norrin Co-receptor that Amplifies Frizzled4 Ligand Selectivity and Signaling."
- reference: PMID:29633588
  title: "Familial Exudative Vitreoretinopathy: Pathophysiology, Diagnosis, and Management."
📚

References & Deep Research

References

11
PMID:20301326
Familial Exudative Vitreoretinopathy, Autosomal Dominant - RETIRED CHAPTER, FOR HISTORICAL REFERENCE ONLY.
No top-level findings curated for this source.
DOI:10.3390/cells12212579
Mechanisms Underlying Rare Inherited Pediatric Retinal Vascular Diseases: FEVR, Norrie Disease, Persistent Fetal Vascular Syndrome
No top-level findings curated for this source.
DOI:10.1111/aos.16701
Clinical and genetic characteristics and natural history of Finnish families with familial exudative vitreoretinopathy due to pathogenic FZD4 variants
No top-level findings curated for this source.
DOI:10.1186/s12886-022-02522-8
Long-term clinical prognosis of 335 infant single-gene positive FEVR cases
No top-level findings curated for this source.
clinicaltrials:NCT05107921
Efficacy of Bromfenac Sodium Hydrate Eye Drops in Children With Familial Exudative Vitreoretinopathy After Diode Laser Photocoagulation
No top-level findings curated for this source.
PMID:15035989
Vascular development in the retina and inner ear: control by Norrin and Frizzled-4, a high-affinity ligand-receptor pair.
No top-level findings curated for this source.
PMID:16929062
Reduced bone mineral density and hyaloid vasculature remnants in a consanguineous recessive FEVR family with a mutation in LRP5.
No top-level findings curated for this source.
PMID:20340138
Overview of the mutation spectrum in familial exudative vitreoretinopathy and Norrie disease with identification of 21 novel variants in FZD4, LRP5, and NDP.
No top-level findings curated for this source.
PMID:25124931
Phenotypic overlap between familial exudative vitreoretinopathy and microcephaly, lymphedema, and chorioretinal dysplasia caused by KIF11 mutations.
No top-level findings curated for this source.
PMID:28658627
TSPAN12 Is a Norrin Co-receptor that Amplifies Frizzled4 Ligand Selectivity and Signaling.
No top-level findings curated for this source.
PMID:29633588
Familial Exudative Vitreoretinopathy: Pathophysiology, Diagnosis, and Management.
No top-level findings curated for this source.

Deep Research

1
Falcon ▸
Disease Characteristics Research Template
Edison Scientific Literature 18 citations 2026-06-17T11:45:53.264926

Question: You are an expert researcher providing comprehensive, well-cited information.

Provide detailed information focusing on: 1. Key concepts and definitions with current understanding 2. Recent developments and latest research (prioritize 2023-2024 sources) 3. Current applications and real-world implementations 4. Expert opinions and analysis from authoritative sources 5. Relevant statistics and data from recent studies

Format as a comprehensive research report with proper citations. Include URLs and publication dates where available. Always prioritize recent, authoritative sources and provide specific citations for all major claims.

Disease Characteristics Research Template

Target Disease

  • Disease Name: Familial Exudative Vitreoretinopathy
  • MONDO ID: (if available)
  • Category: Mendelian

Research Objectives

Please provide a comprehensive research report on Familial Exudative Vitreoretinopathy covering all of the disease characteristics listed below. This report will be used to populate a disease knowledge base entry. Be thorough and cite primary literature (PMID preferred) for all claims.

For each section, suggested databases/resources are listed. These are the first places you should search for information on each topic.

1. Disease Information

Search first: OMIM, Orphanet, ICD-10/ICD-11, MeSH, PubMed

  • What is the disease? Provide a concise overview.
  • What are the key identifiers? (OMIM, Orphanet, ICD-10/ICD-11, MeSH, Mondo)
  • What are the common synonyms and alternative names?
  • Is the information derived from individual patients (e.g., EHR) or aggregated disease-level resources?

2. Etiology

  • Disease Causal Factors: What are the primary causes? (genetic, environmental, infectious, mechanistic)
  • Risk Factors:

    Search first: PubMed, Cochrane Library, UpToDate, clinical guidelines, ClinVar, ClinGen, GWAS Catalog, PheGenI, CTD, CDC, WHO, epidemiological databases

  • Genetic risk factors (causal variants, susceptibility loci, modifier genes)
  • Environmental risk factors (toxins, lifestyle, occupational exposures, age, sex, family history)
  • Protective Factors:

    Search first: PubMed, Cochrane Library, clinical trial databases, GWAS Catalog, gnomAD, WHO, CDC, nutrition databases

  • Genetic protective factors (protective variants, modifier alleles)
  • Environmental protective factors (diet, lifestyle, exposures that reduce risk)
  • Gene-Environment Interactions: How do genetic and environmental factors interact to influence disease?

    Search first: CTD, PubMed, PheGenI, GxE databases

3. Phenotypes

Search first: HPO (Human Phenotype Ontology), OMIM, Orphanet, PubMed, clinicaltrials.gov, MedDRA, SNOMED CT, DECIPHER, LOINC

For each phenotype, provide: - Phenotype type: symptoms, clinical signs, physical manifestations, behavioral changes, or laboratory abnormalities

For symptoms/signs: HPO, OMIM, Orphanet, PubMed For behavioral changes: HPO, DSM, RDoC (Research Domain Criteria), PubMed For laboratory abnormalities: LOINC, SNOMED CT, LabTests Online, PubMed - Phenotype characteristics: Search first: OMIM, Orphanet, HPO, PubMed - Age of symptom onset (neonatal, childhood, adult-onset, late-onset) - Symptom severity (mild, moderate, severe, variable) - Symptom progression (stable, progressive, episodic, fluctuating) - Frequency among affected individuals (percentage or qualitative) - Quality of life impact: Effects on daily functioning and well-being (per-phenotype when possible) Search first: EQ-5D database, SF-36, WHO QOL databases, PubMed - Suggest HPO (Human Phenotype Ontology) terms for each phenotype

4. Genetic/Molecular Information

  • Causal Genes: Gene mutations or chromosomal abnormalities responsible for disease (gene symbols, OMIM IDs)

    Search first: OMIM, ClinVar, HGMD, Ensembl, NCBI Gene

  • Pathogenic Variants:
  • Affected genes (gene symbols, HGNC IDs) > Search first: OMIM, NCBI Gene, Ensembl, HGNC, UniProt, GeneCards
  • Variant classification (pathogenic, likely pathogenic, VUS per ACMG/AMP guidelines) > Search first: ClinVar, ClinGen, ACMG/AMP guidelines, VarSome
  • Variant type/class (missense, frameshift, nonsense, splice-site, structural)
  • Allele frequency in population databases > Search first: gnomAD, 1000 Genomes, ExAC, TOPMed, dbSNP
  • Somatic vs germline origin > Search first: COSMIC (somatic), ClinVar, ICGC, TCGA
  • Functional consequences (loss of function, gain of function, dominant negative)
  • Modifier Genes: Genes that modify disease severity or expression
  • Epigenetic Information: DNA methylation, histone modifications, chromatin changes affecting disease

    Search first: ENCODE, Roadmap Epigenomics, MethBase, DiseaseMeth

  • Chromosomal Abnormalities: Large-scale genetic changes (aneuploidy, translocations, inversions)

    Search first: DECIPHER, ClinVar, ECARUCA, UCSC Genome Browser

5. Environmental Information

  • Environmental Factors: Non-genetic contributing factors (toxins, radiation, pollution, occupational exposure)

    Search first: CTD (Comparative Toxicogenomics Database), TOXNET, PubMed, EPA databases

  • Lifestyle Factors: Behavioral factors (smoking, diet, exercise, alcohol consumption)

    Search first: CDC databases, WHO, PubMed, NHANES

  • Infectious Agents: If applicable, pathogens causing or triggering disease (bacteria, viruses, fungi, parasites)

    Search first: NCBI Taxonomy, ViPR, BV-BRC, MicrobeDB, GIDEON

6. Mechanism / Pathophysiology

  • Molecular Pathways: Specific signaling cascades or biochemical pathways involved (Wnt, MAPK, mTOR, PI3K-AKT, etc.)

    Search first: KEGG, Reactome, WikiPathways, PathBank, BioCyc

  • Cellular Processes: Cell-level mechanisms (apoptosis, autophagy, cell cycle dysregulation, inflammation, etc.)

    Search first: Gene Ontology (GO), Reactome, KEGG, PubMed

  • Protein Dysfunction: How protein structure or function is altered (misfolding, aggregation, loss of function, gain of function)

    Search first: UniProt, PDB (Protein Data Bank), InterPro, Pfam, AlphaFold

  • Metabolic Changes: Alterations in metabolic processes (energy metabolism, lipid metabolism, amino acid metabolism)

    Search first: KEGG, BioCyc, HMDB (Human Metabolome Database), BRENDA

  • Immune System Involvement: Role of immune response (autoimmunity, immunodeficiency, chronic inflammation)

    Search first: ImmPort, Immunome Database, IEDB, Gene Ontology

  • Tissue Damage Mechanisms: How tissues/ are injured (oxidative stress, ischemia, fibrosis, necrosis)

    Search first: PubMed, Gene Ontology, Reactome

  • Biochemical Abnormalities: Specific molecular defects (enzyme deficiencies, receptor dysfunction, ion channel defects)

    Search first: BRENDA, UniProt, KEGG, OMIM, PubMed

  • Epigenetic Changes: DNA methylation, histone modifications affecting gene expression in disease

    Search first: ENCODE, Roadmap Epigenomics, MethBase, DiseaseMeth

  • Molecular Profiling (if available):
  • Transcriptomics/gene expression changes > Search first: GEO (Gene Expression Omnibus), ArrayExpress, GTEx, Human Cell Atlas, SRA
  • Proteomics findings > Search first: PRIDE, ProteomeXchange, Human Protein Atlas, STRING, BioGRID
  • Metabolomics signatures > Search first: MetaboLights, Metabolomics Workbench, HMDB, METLIN
  • Lipidomics alterations > Search first: LIPID MAPS, SwissLipids, LipidHome, Metabolomics Workbench
  • Genomic structural features > Search first: UCSC Genome Browser, Ensembl, NCBI, dbVar, DGV
  • Advanced Technologies (if applicable):
  • Single-cell analysis findings (cell-type specific mechanisms, cellular heterogeneity) > Search first: Human Cell Atlas, Single Cell Portal, GEO, CELLxGENE
  • Spatial transcriptomics findings > Search first: GEO, Spatial Research, Vizgen, 10x Genomics data
  • Multi-omics integration results > Search first: TCGA, ICGC, cBioPortal, LinkedOmics, PubMed
  • Functional genomics screens (CRISPR, RNAi) > Search first: DepMap, GenomeRNAi, PubMed, BioGRID ORCS

For each mechanism, describe: - The causal chain from initial trigger to clinical manifestation - Which mechanisms are upstream vs downstream - What cell types and biological processes are involved - Suggest GO terms for biological processes and CL terms for cell types

7. Anatomical Structures Affected

  • Organ Level:
  • Primary organs directly affected
  • Secondary organ involvement (complications, secondary effects)
  • Body systems involved (cardiovascular, nervous, digestive, respiratory, endocrine, etc.)

    Search first: Uberon, FMA (Foundational Model of Anatomy), OMIM, HPO, ICD-11, MeSH, SNOMED CT

  • Tissue and Cell Level:
  • Specific tissue types affected (epithelial, connective, muscle, nervous)
  • Specific cell populations targeted (with Cell Ontology terms)

    Search first: Uberon, Human Protein Atlas, Cell Ontology, Human Cell Atlas, CellMarker, PanglaoDB

  • Subcellular Level:
  • Cellular compartments involved (mitochondria, nucleus, ER, lysosomes) (with GO Cellular Component terms)

    Search first: Gene Ontology (Cellular Component), UniProt, Human Protein Atlas

  • Localization:
  • Specific anatomical sites (with UBERON terms) > Search first: FMA, Uberon, NeuroNames (for brain), SNOMED CT
  • Lateralization (unilateral, bilateral, asymmetric) > Search first: HPO, clinical literature, imaging databases

8. Temporal Development

  • Onset:
  • Typical age of onset (congenital, pediatric, adult, geriatric)
  • Onset pattern (acute, subacute, chronic, insidious)

    Search first: OMIM, Orphanet, HPO, PubMed

  • Progression:
  • Disease stages (early, intermediate, advanced, end-stage) > Search first: Cancer Staging Manual (AJCC), WHO classifications, PubMed
  • Progression rate (rapid, slow, variable)
  • Disease course pattern (episodic, relapsing-remitting, progressive, stable)
  • Disease duration (self-limited, chronic lifelong)

    Search first: Disease registries, longitudinal cohort databases, natural history studies, PubMed, Orphanet, OMIM

  • Patterns:
  • Remission patterns (spontaneous, treatment-induced) > Search first: Clinical trial databases, disease registries, PubMed
  • Critical periods (time windows of vulnerability or opportunity for intervention) > Search first: PubMed, developmental biology databases, clinical guidelines

9. Inheritance and Population

  • Epidemiology:
  • Prevalence (cases per 100,000 at given time)
  • Incidence (new cases per 100,000 per year)

    Search first: Orphanet, CDC, WHO, GBD (Global Burden of Disease), national registries, SEER, disease registries

  • For Genetic Etiology:
  • Inheritance pattern (AD, AR, X-linked, mitochondrial, multifactorial, polygenic) > Search first: OMIM, Orphanet, ClinVar, GTR (Genetic Testing Registry)
  • Penetrance (complete, incomplete, age-dependent) > Search first: ClinVar, OMIM, PubMed, ClinGen
  • Expressivity (variable, consistent) > Search first: OMIM, ClinVar, PubMed
  • Genetic anticipation (increasing severity in successive generations) > Search first: OMIM, PubMed (especially for repeat expansion disorders)
  • Germline mosaicism > Search first: ClinVar, OMIM, genetic counseling literature, PubMed
  • Founder effects (population-specific mutations) > Search first: gnomAD, population genetics databases, PubMed
  • Consanguinity role > Search first: OMIM, population studies, genetic counseling resources
  • Carrier frequency > Search first: gnomAD, carrier screening databases, GeneReviews, GTR
  • Population Demographics:
  • Affected populations (ethnic or demographic groups with higher prevalence) > Search first: gnomAD, 1000 Genomes, PAGE Study, PubMed, population registries
  • Geographic distribution (endemic areas, regional variation) > Search first: WHO, CDC, GBD, Orphanet, geographic epidemiology databases
  • Geographic distribution of specific variants
  • Sex ratio (male:female) > Search first: Disease registries, OMIM, PubMed, epidemiological databases
  • Age distribution of affected individuals > Search first: CDC, disease registries, SEER, Orphanet

10. Diagnostics

  • Clinical Tests:
  • Laboratory tests (blood, urine, tissue chemistry, specific enzyme assays) > Search first: LOINC, LabTests Online, PubMed
  • Biomarkers (proteins, metabolites, genetic markers, circulating biomarkers) > Search first: FDA Biomarker List, BEST (Biomarkers, EndpointS, and other Tools), PubMed
  • Imaging studies (X-ray, CT, MRI, PET, ultrasound) > Search first: RadLex, DICOM, Radiopaedia, imaging databases
  • Functional tests (pulmonary function, cardiac stress tests) > Search first: LOINC, clinical guidelines, PubMed
  • Electrophysiology (EEG, EMG, ECG, nerve conduction studies) > Search first: LOINC, clinical neurophysiology databases, PubMed
  • Biopsy findings (histopathology, immunohistochemistry) > Search first: SNOMED CT, College of American Pathologists resources, PubMed
  • Pathology findings (microscopic examination) > Search first: SNOMED CT, Digital Pathology databases, PubMed
  • Genetic Testing:

    Search first: GTR (Genetic Testing Registry), GeneReviews, ClinGen

  • Overview of recommended genetic testing approach
  • Whole genome sequencing (WGS) utility > Search first: GTR, ClinVar, GEL (Genomics England), gnomAD
  • Whole exome sequencing (WES) utility > Search first: GTR, ClinVar, OMIM, GeneMatcher
  • Gene panels (which panels, which genes) > Search first: GTR, ClinVar, laboratory-specific databases
  • Single gene testing > Search first: GTR, ClinVar, OMIM, GeneReviews
  • Chromosomal microarray (CMA) > Search first: DECIPHER, ClinVar, dbVar, ECARUCA
  • Karyotyping > Search first: Chromosome Abnormality Database, ClinVar, cytogenetics resources
  • FISH > Search first: ClinVar, cytogenetics databases, PubMed
  • Mitochondrial DNA testing > Search first: MITOMAP, MSeqDR, ClinVar, GTR
  • Repeat expansion testing > Search first: GTR, ClinVar, repeat expansion databases, PubMed
  • Omics-Based Diagnostics (if applicable):
  • RNA sequencing / transcriptomics > Search first: GEO, ArrayExpress, GTEx, RNA-seq databases
  • Proteomics > Search first: PRIDE, ProteomeXchange, FDA Biomarker database
  • Metabolomics > Search first: MetaboLights, Metabolomics Workbench, HMDB
  • Epigenomics > Search first: GEO, ENCODE, Roadmap Epigenomics, MethBase
  • Liquid biopsy > Search first: COSMIC, ClinVar, liquid biopsy databases, PubMed
  • Clinical Criteria:
  • Standardized diagnostic criteria (DSM, ICD, society guidelines) > Search first: DSM-5, ICD-11, clinical society guidelines, UpToDate
  • Differential diagnosis (other conditions to rule out, with distinguishing features) > Search first: DynaMed, UpToDate, clinical decision support systems
  • Screening:
  • Screening methods for asymptomatic individuals (newborn screening, carrier screening, cascade screening) > Search first: ACMG recommendations, CDC newborn screening, GTR

11. Outcome/Prognosis

  • Survival and Mortality:
  • Survival rate (5-year, 10-year, overall) > Search first: SEER, cancer registries, disease-specific registries, PubMed
  • Life expectancy (with and without treatment if applicable) > Search first: Orphanet, disease registries, actuarial databases, PubMed
  • Mortality rate > Search first: CDC, WHO, GBD, national mortality databases
  • Disease-specific mortality (deaths directly attributable to disease) > Search first: Disease registries, CDC Wonder, GBD, PubMed
  • Morbidity and Function:
  • Morbidity (disease-related disability and health impacts) > Search first: GBD, WHO, disability databases, PubMed
  • Disability outcomes (long-term functional impairments) > Search first: ICF (International Classification of Functioning), disability registries
  • Quality of life measures (EQ-5D, SF-36, PROMIS, disease-specific tools) > Search first: EQ-5D database, SF-36, PROMIS, PubMed
  • Disease Course:
  • Complications (secondary problems: infections, organ failure, etc.) > Search first: ICD codes, disease registries, clinical databases, PubMed
  • Recovery potential (likelihood and extent of recovery, with vs without treatment) > Search first: Natural history studies, rehabilitation databases, PubMed
  • Prediction:
  • Prognostic factors (age, disease severity, biomarkers, treatment response) > Search first: Prognostic models databases, clinical calculators, PubMed
  • Prognostic biomarkers (molecular markers predicting disease course) > Search first: FDA Biomarker database, PubMed, cancer prognostic databases

12. Treatment

  • Pharmacotherapy:
  • Pharmacological treatments (drug names, drug classes, mechanisms of action) > Search first: DrugBank, RxNorm, ATC classification, DailyMed, FDA databases
  • Pharmacogenomics (how genetic variants affect drug metabolism, efficacy, toxicity) > Search first: PharmGKB, CPIC (Clinical Pharmacogenetics), FDA Table of PGx Biomarkers
  • Advanced Therapeutics:
  • Gene therapy (viral vectors, CRISPR, gene replacement, gene editing) > Search first: ClinicalTrials.gov, FDA gene therapy database, ASGCT resources
  • Cell therapy (stem cell transplant, CAR-T, cellular therapeutics) > Search first: ClinicalTrials.gov, FDA cell therapy database, FACT standards
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  • Targeted therapies (treatments directed at specific molecular targets) > Search first: My Cancer Genome, OncoKB, ClinicalTrials.gov, FDA approvals
  • Immunotherapies (checkpoint inhibitors, monoclonal antibodies) > Search first: Cancer Immunotherapy Database, FDA approvals, ClinicalTrials.gov
  • Surgical and Interventional:
  • Surgical interventions (types of surgery, timing, outcomes) > Search first: CPT codes, surgical registries, clinical guidelines, PubMed
  • Supportive and Rehabilitative:
  • Supportive care (symptom management, pain control, nutrition) > Search first: Clinical guidelines, Cochrane Library, PubMed
  • Rehabilitation (physical therapy, occupational therapy, speech therapy) > Search first: Rehabilitation medicine databases, clinical guidelines, PubMed
  • Experimental:
  • Experimental treatments in clinical trials (with NCT identifiers if available) > Search first: ClinicalTrials.gov, EU Clinical Trials Register, WHO ICTRP
  • Treatment Outcomes:
  • Treatment response rates > Search first: Clinical trial databases, FDA reviews, systematic reviews, PubMed
  • Side effects and adverse events > Search first: FDA Adverse Event Reporting System (FAERS), MedWatch, PubMed
  • Treatment Strategy:
  • Treatment algorithms (clinical pathways, decision trees) > Search first: Clinical practice guidelines, NCCN Guidelines, UpToDate
  • Combination therapies > Search first: ClinicalTrials.gov, treatment guidelines, PubMed
  • Personalized medicine approaches (genotype-guided treatment) > Search first: My Cancer Genome, CIViC, PharmGKB, precision medicine databases

For each treatment, suggest MAXO (Medical Action Ontology) terms where applicable.

13. Prevention

  • Prevention Levels:
  • Primary prevention (preventing disease occurrence: vaccination, risk factor modification) > Search first: CDC, WHO, USPSTF recommendations, Cochrane Library
  • Secondary prevention (early detection and treatment: screening programs, early intervention) > Search first: USPSTF, CDC screening guidelines, WHO
  • Tertiary prevention (preventing complications in those with disease) > Search first: Clinical guidelines, disease management protocols, PubMed
  • Immunization: Vaccine strategies (if applicable)

    Search first: CDC vaccine schedules, WHO immunization, FDA vaccine database

  • Screening and Early Detection:
  • Screening programs (population-based: newborn screening, cancer screening) > Search first: CDC screening programs, USPSTF, cancer screening databases
  • Genetic screening (carrier screening, preimplantation genetic diagnosis, prenatal testing) > Search first: ACMG recommendations, ACOG guidelines, GTR
  • Risk stratification (identifying high-risk individuals for targeted prevention) > Search first: Risk prediction models, clinical calculators, PubMed
  • Behavioral Interventions: Lifestyle modifications to reduce risk

    Search first: CDC, WHO, behavioral intervention databases, Cochrane Library

  • Counseling: Genetic counseling (risk assessment, family planning guidance)

    Search first: NSGC resources, ACMG guidelines, GeneReviews

  • Public Health:
  • Public health interventions (sanitation, vector control, health education) > Search first: CDC, WHO, public health databases, PubMed
  • Environmental interventions (reducing environmental risk factors) > Search first: EPA databases, WHO environmental health, PubMed
  • Prophylaxis: Preventive medications or procedures

    Search first: Clinical guidelines, FDA approvals, PubMed

14. Other Species / Natural Disease

  • Taxonomy: Species affected (with NCBI Taxon identifiers)

    Search first: NCBI Taxonomy

  • Breed: Specific breeds affected (with VBO identifiers if applicable)

    Search first: VBO (Vertebrate Breed Ontology)

  • Gene: Orthologous genes in other species (with NCBI Gene IDs)

    Search first: NCBI Gene

  • Natural Disease:
  • Naturally occurring disease in other species (companion animals, wildlife) > Search first: OMIA (Online Mendelian Inheritance in Animals), VetCompass, PubMed
  • Veterinary relevance and importance in animal health > Search first: OMIA, veterinary databases, PubMed
  • Comparative Biology:
  • Comparative pathology (similarities and differences across species) > Search first: OMIA, comparative pathology databases, PubMed
  • Evolutionary conservation of disease mechanisms > Search first: HomoloGene, OrthoMCL, Alliance of Genome Resources
  • Transmission (if applicable):
  • Zoonotic potential > Search first: CDC zoonotic diseases, WHO zoonoses, GIDEON
  • Cross-species susceptibility > Search first: NCBI Taxonomy, veterinary databases, PubMed

15. Model Organisms

  • Model Types:
  • Model organism type (mammalian, invertebrate, cellular, in vitro) > Search first: Alliance of Genome Resources, model organism databases
  • Specific model systems (mouse, rat, zebrafish, Drosophila, C. elegans, yeast, cell lines, organoids, iPSCs) > Search first: MGI, RGD, ZFIN, FlyBase, WormBase, SGD, ATCC, Cellosaurus
  • Induced models (drug treatment, surgical intervention, environmental manipulation) > Search first: MGI, model organism databases, PubMed
  • Genetic Models:
  • Types available (knockout, knock-in, transgenic, conditional, humanized) > Search first: MGI, IMPC, KOMP, EuMMCR, IMSR
  • Model Characteristics:
  • Phenotype recapitulation (how well model reproduces human disease features) > Search first: Model organism databases, comparative studies, PubMed
  • Model limitations (aspects of human disease not captured) > Search first: Model organism databases, PubMed, review articles
  • Applications:
  • Research applications (what aspects of disease can be studied) > Search first: Model organism databases, PubMed
  • Resources:
  • Model databases > Search first: MGI, RGD, ZFIN, FlyBase, WormBase, IMSR, EMMA, MMRRC

Citation Requirements

  • Cite primary literature (PMID preferred) for all mechanistic and clinical claims
  • Prioritize recent reviews and landmark papers
  • Include direct quotes from abstracts where possible to support key statements
  • Distinguish evidence source types: human clinical, model organism, in vitro, computational

Output Format

Structure your response as a comprehensive narrative organized by the sections above. For each section, provide: - Factual content with specific details (numbers, percentages, gene names, variant nomenclature) - Ontology term suggestions (HPO, GO, CL, UBERON, CHEBI, MAXO, MONDO) where applicable - Evidence citations with PMIDs - Direct quotes from abstracts to support key claims - Clear indication when information is not available or not applicable for this disease

This report will be used to populate a disease knowledge base entry with: - Pathophysiology descriptions with causal chains - Gene/protein annotations (HGNC, GO terms) - Phenotype associations (HP terms) with frequencies - Cell type involvement (CL terms) - Anatomical locations (UBERON terms) - Chemical entities (CHEBI terms) - Treatment annotations (MAXO terms) - Evidence items with PMIDs and exact abstract quotes - Epidemiology, prognosis, diagnostic, and prevention information - Animal model descriptions with phenotype recapitulation details

Familial Exudative Vitreoretinopathy (FEVR) — Disease Characteristics Research Report (Mendelian)

Executive summary

Familial exudative vitreoretinopathy (FEVR) is an inherited developmental retinal vascular disorder characterized by incomplete/aberrant vascularization of the peripheral retina, producing an avascular periphery that can be asymptomatic early but predisposes to ischemia-driven neovascularization, exudation, vitreoretinal traction, and retinal detachment. (tauqeer2018familialexudativevitreoretinopathy pages 1-1, lahteenoja2024clinicalandgenetic pages 1-2)

Current understanding (2023–2024 emphasis): recent synthesis highlights retinal endothelial-cell dysfunction and impaired inner blood–retinal barrier (iBRB) development/maintenance as core biology, with the canonical Norrin–Wnt/β-catenin pathway (NDP–FZD4–LRP5 with TSPAN12 modulation) central, and additional genes (e.g., CTNNB1, KIF11, ZNF408, CTNNA1) expanding genetic heterogeneity. (le2023mechanismsunderlyingrare pages 2-4, lahteenoja2024clinicalandgenetic pages 1-2)

1. Disease information

1.1 Definition/overview

  • A widely cited clinical review describes FEVR as a heritable vitreoretinopathy with anomalous retinal vascular development whose principal feature is peripheral avascular retina, with risk of neovascularization, exudation, hemorrhage, fibrovascular membranes, vitreoretinal traction and retinal detachment. (tauqeer2018familialexudativevitreoretinopathy pages 1-1)
  • A natural-history study in Finnish families similarly defines FEVR as an inherited retinal disorder with “failure of peripheral retinal vascularisation,” with peripheral avascularity leading to ischemia and downstream neovascular and tractional sequelae. (lahteenoja2024clinicalandgenetic pages 1-2)
  • A mechanistic 2023 review summarizes FEVR as an inherited disorder with “partial to complete failure of retinal vasculature formation,” leaving the peripheral retina “avascular and hypoxic.” (le2023mechanismsunderlyingrare pages 2-4)

1.2 Key identifiers (availability within tool-retrieved evidence)

The current tool-retrieved corpus did not include authoritative OMIM/Orphanet/MONDO/ICD/MeSH records directly, so identifiers below are limited to what appeared in retrieved primary literature: - OMIM disease number (literature-cited): FEVR (OMIM/MIM 133780) appears in peer-reviewed articles. (tauqeer2018familialexudativevitreoretinopathy pages 1-2) - MONDO ID / Orphanet ORPHA / ICD-10/ICD-11 / MeSH: not extractable from the retrieved full texts in this run; should be populated from OMIM/Orphanet/MONDO registries directly.

1.3 Synonyms/alternative names

  • “Familial exudative vitreoretinopathy” (FEVR) is the dominant term across clinical and mechanistic literature. (tauqeer2018familialexudativevitreoretinopathy pages 1-1, le2023mechanismsunderlyingrare pages 2-4)
  • FEVR is often discussed alongside Norrie disease and other pediatric retinal vascular disorders due to shared pathway biology (Norrin/Wnt). (le2023mechanismsunderlyingrare pages 2-4)

1.4 Evidence source type

Most information in this report is from: - Aggregated disease-level resources: reviews and cohort/natural history studies. (tauqeer2018familialexudativevitreoretinopathy pages 1-1, lahteenoja2024clinicalandgenetic pages 1-2, le2023mechanismsunderlyingrare pages 2-4) - Human clinical observational cohorts: infant cohort (n=335 gene-positive infants) and Finnish family cohort (n=35 variant-positive individuals). (chen2022longtermclinicalprognosis pages 1-2, lahteenoja2024clinicalandgenetic pages 1-2) - Clinical research protocol database (ClinicalTrials.gov): NIH observational study with gene frequency estimates. (NCT00106756 chunk 1)

2. Etiology

2.1 Disease causal factors

Primary cause: germline genetic variation affecting retinal vascular development. - The 2018 clinical review states FEVR is genetically heterogeneous and that “The Wnt signaling pathway is implicated and likely at the core of this retinal developmental abnormality.” (tauqeer2018familialexudativevitreoretinopathy pages 6-7) - The 2023 mechanistic review links abnormal angiogenesis/iBRB development to pathogenic variants in Norrin–Wnt pathway genes (NDP, FZD4, TSPAN12, LRP5) and additional genes (CTNNB1, KIF11, ZNF408, CTNND1, CTNNA1, EMC1). (le2023mechanismsunderlyingrare pages 2-4)

Direct abstract quotes (mechanistic review, 2023): - “The early angiogenesis of the retina and its iBRB is a delicate process that is mediated by the canonical Norrin Wnt-signaling pathway in retinal endothelial cells.” (le2023mechanismsunderlyingrare pages 2-4) - “Pathogenic variants in genes that play key roles within this pathway, such as NDP, FZD4, TSPAN12, and LRP5, have been associated with the incidence of these retinal diseases.” (le2023mechanismsunderlyingrare pages 2-4)

2.2 Risk factors

Genetic risk factors (causal genes; Mendelian): - Commonly implicated genes include FZD4, LRP5, NDP, TSPAN12, and additional genes/loci such as ZNF408 and KIF11. (tauqeer2018familialexudativevitreoretinopathy pages 1-2, tauqeer2018familialexudativevitreoretinopathy pages 1-1) - The NIH observational protocol notes that FZD4 may account for “~20–30% of autosomal dominant cases” and LRP5 “~15% of cases,” with NDP underlying many X-linked cases (as summarized in the trial record). (NCT00106756 chunk 1)

Penetrance/expressivity: - Review-level synthesis reports “high penetrance (75–100%) and variable expressivity.” (tauqeer2018familialexudativevitreoretinopathy pages 1-2) - In contrast, the Finnish FZD4 cohort found that only 34% (12/35) of variant-positive individuals had been clinically diagnosed with FEVR, underscoring under-recognition and/or mild/subclinical disease. (lahteenoja2024clinicalandgenetic pages 1-2)

Non-genetic risk factors: - No robust environmental/lifestyle risk factors were identified in the retrieved evidence; FEVR is primarily genetic in etiology.

2.3 Protective factors

No specific genetic or environmental protective factors were identified in the retrieved evidence.

2.4 Gene–environment interactions

No specific gene–environment interaction evidence was identified in the retrieved evidence.

3. Phenotypes

3.1 Core phenotype spectrum (symptoms/signs)

Across clinical sources, typical manifestations include: - Peripheral avascular retina / abnormal peripheral vascularization (often asymptomatic early). (tauqeer2018familialexudativevitreoretinopathy pages 1-1, lahteenoja2024clinicalandgenetic pages 1-2) - Neovascularization and exudation, vitreous hemorrhage, fibrovascular membranes, vitreoretinal traction, retinal folds, and tractional/rhegmatogenous retinal detachment in progressive disease. (tauqeer2018familialexudativevitreoretinopathy pages 1-1, lahteenoja2024clinicalandgenetic pages 1-2)

Staging: - The 2023 mechanistic review includes a standard clinical staging from mild avascular periphery to total retinal detachment: stage 1 (avascular peripheral retina) through stage 5 (total retinal detachment). (le2023mechanismsunderlyingrare pages 2-4) - The 2022 infant cohort describes staging using Pendergast’s classification (Stage 0–5; Stage 1–3 considered mild; Stage 4–5 severe). (chen2022longtermclinicalprognosis pages 1-2)

3.2 Age of onset, severity, progression

  • Finnish FZD4 cohort: “The median age of the onset of symptoms was 2.3 years, ranging between 0 to 25 years.” (lahteenoja2024clinicalandgenetic pages 1-2)
  • Disease severity is variable, even among relatives with the same variant. (lahteenoja2024clinicalandgenetic pages 1-2)

3.3 Phenotype frequencies/statistics (from recent cohorts)

Finnish FZD4 families (Acta Ophthalmologica, publication May 2024; URL: https://doi.org/10.1111/aos.16701): - Only 34% (12/35) variant-positive individuals had been clinically diagnosed with FEVR. (lahteenoja2024clinicalandgenetic pages 1-2) - Most common eye stage was stage 1 (avascular periphery/abnormal vascularization) in 40% of eyes (28/70). (lahteenoja2024clinicalandgenetic pages 1-2) - Myopia was present in 62% of eyes (31/50). (lahteenoja2024clinicalandgenetic pages 1-2) - Visual impairment: 94% not visually impaired; 6% severe visual impairment. (lahteenoja2024clinicalandgenetic pages 1-2)

Infant single-gene positive cohort (BMC Ophthalmology, publication Aug 2022; URL: https://doi.org/10.1186/s12886-022-02522-8): - Strabismus at first visit: 20% (67/335). (chen2022longtermclinicalprognosis pages 1-2) - Genotype–severity: NDP most severe; ZNF408 mildest (cohort-level statement). (chen2022longtermclinicalprognosis pages 1-2)

3.4 Quality-of-life impact

The retrieved evidence did not include standardized QoL instruments (e.g., EQ-5D, VFQ) for FEVR; functional impact is inferred from visual acuity loss and retinal detachment risk.

3.5 Suggested HPO terms (examples; map to local ontology implementation)

Based on reported clinical features in the retrieved sources: - Peripheral avascular retina / abnormal retinal vascularization → Abnormality of retinal vasculature (HP:0001103) (proxy; local curation may require more specific terms) (tauqeer2018familialexudativevitreoretinopathy pages 1-1, lahteenoja2024clinicalandgenetic pages 1-2) - Retinal neovascularization → Retinal neovascularization (HP:0007894) (tauqeer2018familialexudativevitreoretinopathy pages 1-1, lahteenoja2024clinicalandgenetic pages 1-2) - Retinal exudates → Retinal exudate (HP:0008030) (tauqeer2018familialexudativevitreoretinopathy pages 1-1, lahteenoja2024clinicalandgenetic pages 1-2) - Vitreous hemorrhage → Vitreous hemorrhage (HP:0007900) (lahteenoja2024clinicalandgenetic pages 1-2) - Retinal detachment (tractional/total) → Retinal detachment (HP:0000541) (le2023mechanismsunderlyingrare pages 2-4) - Retinal fold → Retinal fold (HP:0000552) (lahteenoja2024clinicalandgenetic pages 1-2) - Myopia → Myopia (HP:0000545) (lahteenoja2024clinicalandgenetic pages 1-2) - Strabismus → Strabismus (HP:0000486) (chen2022longtermclinicalprognosis pages 1-2)

4. Genetic / molecular information

4.1 Causal genes (current understanding)

Recent and established evidence supports a core set of genes and a growing long tail of additional contributors.

Gene Typical inheritance in FEVR Mechanistic note Key support
FZD4 Usually autosomal dominant; recurrent cause in multiple cohorts Encodes Frizzled-4, the Norrin receptor in retinal endothelial cells; core Norrin/Wnt/β-catenin pathway gene required for retinal vascularization and iBRB development/maintenance (NCT00106756 chunk 1, lahteenoja2024clinicalandgenetic pages 1-2, le2023mechanismsunderlyingrare pages 2-4, tauqeer2018familialexudativevitreoretinopathy pages 1-2)
LRP5 Autosomal dominant or autosomal recessive Wnt co-receptor partnering with FZD4/Norrin signaling; core Norrin/Wnt/β-catenin pathway gene; disruption impairs retinal angiogenesis (tauqeer2018familialexudativevitreoretinopathy pages 1-1, NCT00106756 chunk 1, lahteenoja2024clinicalandgenetic pages 1-2, tauqeer2018familialexudativevitreoretinopathy pages 1-2)
NDP X-linked Encodes Norrin ligand; activates FZD4/LRP5 signaling in retinal endothelial cells; core Norrin/Wnt/β-catenin pathway gene; often associated with more severe phenotypes in infant cohorts (NCT00106756 chunk 1, lahteenoja2024clinicalandgenetic pages 1-2, le2023mechanismsunderlyingrare pages 2-4, chen2022longtermclinicalprognosis pages 1-2)
TSPAN12 Usually autosomal dominant Tetraspanin that amplifies/stabilizes Norrin-FZD4-LRP5 signaling; core Norrin/Wnt/β-catenin pathway gene (tauqeer2018familialexudativevitreoretinopathy pages 1-1, lahteenoja2024clinicalandgenetic pages 1-2, le2023mechanismsunderlyingrare pages 2-4, tauqeer2018familialexudativevitreoretinopathy pages 1-2)
ZNF408 Autosomal dominant (reported) FEVR-associated gene generally considered outside the canonical Norrin/Wnt core module; linked to retinal vascular development with typically milder phenotype in one infant cohort (tauqeer2018familialexudativevitreoretinopathy pages 1-1, chen2022longtermclinicalprognosis pages 1-2, le2023mechanismsunderlyingrare pages 2-4, tauqeer2018familialexudativevitreoretinopathy pages 1-2)
KIF11 Autosomal dominant Non-Wnt motor protein gene; associated with syndromic/non-syndromic FEVR and variable expressivity, often severe retinal detachment in probands; mechanism considered outside core Norrin/Wnt pathway (tauqeer2018familialexudativevitreoretinopathy pages 1-1, le2023mechanismsunderlyingrare pages 2-4, tauqeer2018familialexudativevitreoretinopathy pages 1-2)
CTNNB1 Reported in dominant and syndromic FEVR-spectrum disease Encodes β-catenin, the central downstream effector of canonical Wnt signaling; therefore part of the Norrin/Wnt/β-catenin axis rather than an upstream ligand/receptor component (lahteenoja2024clinicalandgenetic pages 1-2, le2023mechanismsunderlyingrare pages 2-4)
CTNNA1 Reported as FEVR-linked / candidate in recent literature Encodes α-catenin 1; recent evidence places it among newer FEVR-associated genes, likely affecting vascular development/cell-adhesion biology and interacting with catenin signaling; not a classic core Norrin ligand-receptor gene (lahteenoja2024clinicalandgenetic pages 1-2, le2023mechanismsunderlyingrare pages 2-4)

Table: This table summarizes major genes implicated in familial exudative vitreoretinopathy, their usual inheritance patterns, and whether they map to the core Norrin/Wnt/β-catenin pathway or to other mechanisms. It is useful for concise genotype-mechanism mapping in a disease knowledge base.

Key points: - The 2023 review emphasizes that, beyond NDP/FZD4/TSPAN12/LRP5, “additional genes such as CTNNB1, KIF11, and ZNF408… operate outside of the Norrin Wnt-signaling pathway,” with newer associations including CTNND1, CTNNA1, EMC1. (le2023mechanismsunderlyingrare pages 2-4) - The 2024 Finnish cohort notes that multiple implicated genes exist and explicitly places FZD4, TSPAN12, NDP, LRP5, CTNNB1, CTNNA1 in the Norrin/Wnt pathway. (lahteenoja2024clinicalandgenetic pages 1-2)

4.2 Inheritance patterns

  • Inheritance can be autosomal dominant (most common), autosomal recessive, or X-linked. (tauqeer2018familialexudativevitreoretinopathy pages 1-1, NCT00106756 chunk 1, chen2022longtermclinicalprognosis pages 1-2)
  • Example curation statement: “Variations in the FZD4… TSPAN12… and ZNF408… genes have autosomal dominant inheritance, whereas variations in LRP5… have autosomal dominant or recessive inheritance and variations in NDP… have X-linked inheritance.” (tauqeer2018familialexudativevitreoretinopathy pages 1-1)

4.3 Pathogenic variant mechanisms (functional consequences)

While variant-level functional data are heterogeneous, the disease-level mechanistic direction supported by the retrieved evidence is predominantly loss of effective Norrin/Wnt signaling in retinal endothelial cells: - Central pathway statement: Norrin binding to Frizzled-4 with LRP5 co-receptor implicates disrupted Norrin/Wnt signaling in abnormal retinal angiogenesis. (lahteenoja2024clinicalandgenetic pages 1-2) - Downstream effector: β-catenin (CTNNB1) is a central mediator of canonical Wnt signaling relevant to FEVR. (le2023mechanismsunderlyingrare pages 2-4)

Variant classification (ACMG/ClinVar): not extractable from the retrieved evidence set.

Population allele frequencies (gnomAD): not extractable from the retrieved evidence set.

4.4 Modifier genes / epigenetics / chromosomal abnormalities

No specific modifier genes or epigenetic signatures were extractable from the retrieved evidence.

5. Environmental information

FEVR is primarily genetic; no specific environmental toxins, lifestyle exposures, or infectious triggers were identified in the retrieved evidence.

6. Mechanism / pathophysiology

6.1 Core molecular pathway: Norrin–Wnt/β-catenin signaling in retinal endothelial cells

  • The 2018 clinical review: “The Wnt signaling pathway is implicated and likely at the core of this retinal developmental abnormality.” (tauqeer2018familialexudativevitreoretinopathy pages 6-7)
  • The 2023 mechanistic review emphasizes retinal endothelial cells (RECs) and iBRB development:
  • “The early angiogenesis of the retina and its iBRB is a delicate process that is mediated by the canonical Norrin Wnt-signaling pathway in retinal endothelial cells.” (le2023mechanismsunderlyingrare pages 2-4)

6.2 Causal chain (upstream → downstream)

  1. Germline pathogenic variants in Norrin/Wnt pathway genes (e.g., NDP, FZD4, LRP5, TSPAN12) or other genes affecting vascular development. (le2023mechanismsunderlyingrare pages 2-4, tauqeer2018familialexudativevitreoretinopathy pages 1-2)
  2. Impaired retinal angiogenesis during development → peripheral avascular retina (stage 1 disease). (le2023mechanismsunderlyingrare pages 2-4)
  3. Peripheral hypoxia/ischemia in avascular retina → pathologic neovascularization/exudation and fibrovascular proliferation. (lahteenoja2024clinicalandgenetic pages 1-2, tauqeer2018familialexudativevitreoretinopathy pages 1-1)
  4. Vitreoretinal traction, folds, and detachments leading to vision loss. (tauqeer2018familialexudativevitreoretinopathy pages 1-1, lahteenoja2024clinicalandgenetic pages 1-2)

6.3 Cellular processes and cell types

  • Cell type: retinal endothelial cells (RECs) are explicitly central in the 2023 mechanistic synthesis. (le2023mechanismsunderlyingrare pages 2-4)
  • Barrier biology: iBRB formation/maintenance is highlighted as coupled to angiogenesis, with endothelial junctional and transcytosis regulation. (le2023mechanismsunderlyingrare pages 2-4)

6.4 Suggested GO and CL terms (examples)

Based on the pathway and processes described: - GO Biological Process: retinal blood vessel development, angiogenesis, canonical Wnt signaling pathway, blood–retinal barrier establishment/maintenance (le2023mechanismsunderlyingrare pages 2-4) - CL Cell type: retinal endothelial cell (CL mapping typically to endothelial cell subclasses; local implementation needed) (le2023mechanismsunderlyingrare pages 2-4)

7. Anatomical structures affected

7.1 Organ/tissue localization

  • Primary: retina, especially peripheral retina with arrested vascularization. (tauqeer2018familialexudativevitreoretinopathy pages 1-1, lahteenoja2024clinicalandgenetic pages 1-2)
  • Complications involve vitreoretinal interface and tractional pathology. (tauqeer2018familialexudativevitreoretinopathy pages 1-1)

7.2 Suggested UBERON terms (examples)

  • Retina (UBERON:0000966)
  • Peripheral retina (often modeled as a region of retina; local UBERON mapping)
  • Vitreous body (UBERON:0000970) for vitreous hemorrhage/traction context (lahteenoja2024clinicalandgenetic pages 1-2)

8. Temporal development

8.1 Onset

  • Often pediatric/early-life but variable: Finnish cohort median symptom onset 2.3 years (range 0–25). (lahteenoja2024clinicalandgenetic pages 1-2)

8.2 Progression

  • Spectrum from asymptomatic peripheral avascularity to progressive proliferative/tractional disease with retinal detachment. (tauqeer2018familialexudativevitreoretinopathy pages 1-1, le2023mechanismsunderlyingrare pages 2-4)

9. Inheritance and population

9.1 Epidemiology

  • A 2017 genetics-testing summary states “There is insufficient data to determine the prevalence of FEVR” (within its abstract). (tauqeer2018familialexudativevitreoretinopathy pages 1-1)
  • The infant cohort contains prevalence-like statements and broad ranges (e.g., “high risk of retinal detachment (21–64%)”), but these appear as compiled/secondary figures in the excerpted context rather than a population prevalence estimate. (chen2022longtermclinicalprognosis pages 1-2)

9.2 Penetrance and expressivity

  • Review-level penetrance estimate: “high penetrance (75–100%)” with variable expressivity. (tauqeer2018familialexudativevitreoretinopathy pages 1-2)
  • Real-world under-diagnosis in variant-positive relatives: only 34% clinically diagnosed in Finnish FZD4 families. (lahteenoja2024clinicalandgenetic pages 1-2)

9.3 Founder effects

  • Finnish cohort: “Shared haplotypes extending approximately 0.9 Mb around the recurrent FZD4 c.313A>G variant were identified,” consistent with a founder/recurrent variant scenario in that population. (lahteenoja2024clinicalandgenetic pages 1-2)

10. Diagnostics

10.1 Clinical/imaging tests

  • Fluorescein angiography is emphasized as essential:
  • “wide-field fluorescein angiography has become the gold standard in the diagnosis and monitoring of these patients.” (tauqeer2018familialexudativevitreoretinopathy pages 6-7)
  • Finnish cohort used wide-field imaging and fluorescein angiography (FAG) for evaluation. (lahteenoja2024clinicalandgenetic pages 1-2)

10.2 Genetic testing

  • Review-level yield estimate: “Genetic testing yields mutations in ~40–50% of diagnosed patients,” with ~50% of genetically confirmed cases explained by core Wnt-related genes (as summarized in the review text). (tauqeer2018familialexudativevitreoretinopathy pages 1-2)
  • The NIH ClinicalTrials.gov protocol includes genetic testing from blood and reports approximate contribution of FZD4 and LRP5 in cases. (NCT00106756 chunk 1)

10.3 Differential diagnosis

Not systematically extractable from the retrieved evidence; however, FEVR is frequently discussed in the differential of pediatric peripheral retinal vascular anomalies and may be confused with related entities (e.g., Norrie disease, PFVS, retinopathy of prematurity), per mechanistic comparisons. (le2023mechanismsunderlyingrare pages 2-4)

10.4 Screening

  • Family screening is supported by the concept that relatives can have subtle vascular changes detectable by angiography; wide-field FA supports early detection/screening (review-level). (tauqeer2018familialexudativevitreoretinopathy pages 1-1)

11. Outcome / prognosis

11.1 Visual outcomes and surgical prognosis (cohort statistics)

Infant gene-positive cohort (n=335; follow-up 2–10 years): - Lens-sparing vitrectomy lens transparency: 78.58% (11/14) remained transparent after LSV (text; supported by extracted visual tables/figures). (chen2022longtermclinicalprognosis pages 1-2, chen2022longtermclinicalprognosis media 676d4771) - Vision: at last follow-up, 20% (60/300) had vision >20/200. (chen2022longtermclinicalprognosis pages 1-2, chen2022longtermclinicalprognosis media 676d4771)

Finnish FZD4 cohort: - Median visual acuity 0.1 logMAR (0.8 Snellen decimal), range light perception to −0.1 logMAR; 94% not visually impaired; 6% severe visual impairment. (lahteenoja2024clinicalandgenetic pages 1-2)

11.2 Prognostic factors

  • Genotype–severity association in infant cohort: NDP most severe; ZNF408 mildest (cohort-level). (chen2022longtermclinicalprognosis pages 1-2)

12. Treatment

12.1 Standard interventional management (current practice)

The core management goal is to prevent progression and treat complications: - The 2018 review: “The current treatment paradigm involves laser photocoagulation of [the] avascular peripheral retina for neovascular sequelae and vitreoretinal surgery for progressive retinal detachment.” (tauqeer2018familialexudativevitreoretinopathy pages 1-1) - “Early laser photocoagulation helps to prevent progression of disease.” (tauqeer2018familialexudativevitreoretinopathy pages 6-7)

Anti-VEGF: - Anti-VEGF use (e.g., intravitreal bevacizumab/pegaptanib) is mentioned as part of therapeutic options in the review. (tauqeer2018familialexudativevitreoretinopathy pages 7-7)

Vitrectomy / surgical repair: - The 2018 review summarizes surgical reattachment rates as variable across series and notes surgical risks (iatrogenic breaks). (tauqeer2018familialexudativevitreoretinopathy pages 6-7) - Infant cohort: Stage 4–5 often treated with transcorneal vitrectomy with lensectomy or lens-sparing vitrectomy; earlier onset associated with worse prognosis; “Active surgical intervention and lens sparing were necessary for cases at Stage 4–5.” (chen2022longtermclinicalprognosis pages 1-2)

12.2 Treatment outcomes (selected statistics)

  • Infant cohort: Stage 1–3 treated with intravitreal injection and/or retinal photocoagulation with last follow-up vision “above 20/67” (cohort-level statement). (chen2022longtermclinicalprognosis pages 1-2)
  • Infant cohort: LSV lens transparency 78.58% (11/14); last follow-up vision >20/200 in 20% (60/300). (chen2022longtermclinicalprognosis pages 1-2, chen2022longtermclinicalprognosis media 676d4771)

12.3 Experimental / trials (ClinicalTrials.gov)

  • NCT00106756 (NIH/NEI; observational; completed; first posted 2005): “Clinical and Genetic Studies of Familial Exudative Vitreoretinopathy” focuses on phenotyping (fluorescein angiography) and genetic contributions, providing gene frequency context (FZD4 ~20–30% of AD cases; LRP5 ~15%). URL: https://clinicaltrials.gov/study/NCT00106756 (NCT00106756 chunk 1)
  • NCT05107921 (Seoul National University Hospital; Phase 2; bromfenac eye drops in FEVR; status unknown). URL: https://clinicaltrials.gov/study/NCT05107921 (NCT00106756 chunk 1)

12.4 Suggested MAXO terms (examples)

  • Laser photocoagulation of retina (MAXO term for retinal laser photocoagulation)
  • Intravitreal injection therapy / anti-VEGF therapy (MAXO term for intravitreal drug administration)
  • Vitrectomy / vitreoretinal surgery (MAXO term for vitrectomy)
  • Genetic testing (MAXO term for molecular genetic testing)

13. Prevention

Because FEVR is genetic, primary prevention is not established. Practical prevention focuses on preventing vision-threatening complications: - Secondary prevention: early detection of peripheral avascularity and neovascular activity via wide-field fluorescein angiography and family screening. (tauqeer2018familialexudativevitreoretinopathy pages 6-7, tauqeer2018familialexudativevitreoretinopathy pages 1-1) - Tertiary prevention: timely laser/surgery to prevent progression to detachment and irreversible vision loss. (tauqeer2018familialexudativevitreoretinopathy pages 1-1, chen2022longtermclinicalprognosis pages 1-2)

14. Other species / natural disease

The retrieved evidence supports the use of animal models (mouse) for pathway validation (e.g., defective vascular growth with FZD4 disruption), but did not provide naturally occurring veterinary disease analogs. (tauqeer2018familialexudativevitreoretinopathy pages 1-2)

15. Model organisms

  • Review-level synthesis notes that mouse studies support that loss of FZD4 causes defective vascular growth, impaired endothelial migration, and hyperpermeable vessels, consistent with a core developmental angiogenesis mechanism. (tauqeer2018familialexudativevitreoretinopathy pages 1-2)

Recent developments and expert synthesis (2023–2024 prioritized)

  1. Expanded gene discovery beyond core Norrin/Wnt module: 2023 mechanistic review emphasizes multigenic architecture and highlights additional genes (CTNNB1, KIF11, ZNF408, CTNND1, CTNNA1, EMC1) impacting retinal vasculature, including syndromic overlap. (le2023mechanismsunderlyingrare pages 2-4)
  2. Population-specific natural history / under-diagnosis: 2024 Finnish families study quantified that only 34% of variant-positive individuals were clinically diagnosed and that most eyes were mild stage 1, supporting the need for angiographic family screening. (lahteenoja2024clinicalandgenetic pages 1-2)

Key URLs and publication dates (from retrieved evidence)

  • Le et al. 2023-11 (Cells): https://doi.org/10.3390/cells12212579 (le2023mechanismsunderlyingrare pages 2-4)
  • Lähteenoja et al. 2024-05 (Acta Ophthalmologica): https://doi.org/10.1111/aos.16701 (lahteenoja2024clinicalandgenetic pages 1-2)
  • Chen et al. 2022-08 (BMC Ophthalmology): https://doi.org/10.1186/s12886-022-02522-8 (chen2022longtermclinicalprognosis pages 1-2)
  • Tauqeer & Yonekawa 2018-04 (Asia-Pacific J Ophthalmology): https://doi.org/10.22608/apo.201855 (tauqeer2018familialexudativevitreoretinopathy pages 1-1)
  • ClinicalTrials.gov NCT00106756 (posted 2005; NIH/NEI): https://clinicaltrials.gov/study/NCT00106756 (NCT00106756 chunk 1)

Limitations of this run

  • Direct extraction of Orphanet ORPHA, MONDO ID, ICD-10/ICD-11, and MeSH identifiers was not possible from the retrieved full-text corpus; these should be added from their authoritative registries.
  • Variant-level ClinVar classifications, allele frequencies (gnomAD), and detailed differential diagnosis lists were not available in the retrieved evidence set.

References

  1. (tauqeer2018familialexudativevitreoretinopathy pages 1-1): Z. Tauqeer and Y. Yonekawa. Familial exudative vitreoretinopathy: pathophysiology, diagnosis, and management. Asia-Pacific Journal of Ophthalmology, 7:176–182, Apr 2018. URL: https://doi.org/10.22608/apo.201855, doi:10.22608/apo.201855. This article has 116 citations and is from a peer-reviewed journal.

  2. (lahteenoja2024clinicalandgenetic pages 1-2): Laura Lähteenoja, Tapani Palosaari, Timo Tiirikka, Maria Haanpää, Jukka Moilanen, Aura Falck, and Elisa Rahikkala. Clinical and genetic characteristics and natural history of finnish families with familial exudative vitreoretinopathy due to pathogenic fzd4 variants. Acta Ophthalmologica, 103:152-161, May 2024. URL: https://doi.org/10.1111/aos.16701, doi:10.1111/aos.16701. This article has 3 citations and is from a domain leading peer-reviewed journal.

  3. (le2023mechanismsunderlyingrare pages 2-4): Vincent Le, Gabrielle Abdelmessih, Wendy A Dailey, Cecille Pinnock, Victoria Jobczyk, Revati Rashingkar, Kimberly A Drenser, and Kenneth P Mitton. Mechanisms underlying rare inherited pediatric retinal vascular diseases: fevr, norrie disease, persistent fetal vascular syndrome. Cells, Nov 2023. URL: https://doi.org/10.3390/cells12212579, doi:10.3390/cells12212579. This article has 30 citations.

  4. (tauqeer2018familialexudativevitreoretinopathy pages 1-2): Z. Tauqeer and Y. Yonekawa. Familial exudative vitreoretinopathy: pathophysiology, diagnosis, and management. Asia-Pacific Journal of Ophthalmology, 7:176–182, Apr 2018. URL: https://doi.org/10.22608/apo.201855, doi:10.22608/apo.201855. This article has 116 citations and is from a peer-reviewed journal.

  5. (chen2022longtermclinicalprognosis pages 1-2): Chunli Chen, Yi‐Chang Cheng, Zhihan Zhang, Xiang Zhang, Jiakai Li, Peiquan Zhao, and Xiaoyan Peng. Long-term clinical prognosis of 335 infant single-gene positive fevr cases. BMC Ophthalmology, Aug 2022. URL: https://doi.org/10.1186/s12886-022-02522-8, doi:10.1186/s12886-022-02522-8. This article has 13 citations and is from a peer-reviewed journal.

  6. (NCT00106756 chunk 1): Clinical and Genetic Studies of Familial Exudative Vitreoretinopathy. National Eye Institute (NEI). 2005. ClinicalTrials.gov Identifier: NCT00106756

  7. (tauqeer2018familialexudativevitreoretinopathy pages 6-7): Z. Tauqeer and Y. Yonekawa. Familial exudative vitreoretinopathy: pathophysiology, diagnosis, and management. Asia-Pacific Journal of Ophthalmology, 7:176–182, Apr 2018. URL: https://doi.org/10.22608/apo.201855, doi:10.22608/apo.201855. This article has 116 citations and is from a peer-reviewed journal.

  8. (chen2022longtermclinicalprognosis media 676d4771): Chunli Chen, Yi‐Chang Cheng, Zhihan Zhang, Xiang Zhang, Jiakai Li, Peiquan Zhao, and Xiaoyan Peng. Long-term clinical prognosis of 335 infant single-gene positive fevr cases. BMC Ophthalmology, Aug 2022. URL: https://doi.org/10.1186/s12886-022-02522-8, doi:10.1186/s12886-022-02522-8. This article has 13 citations and is from a peer-reviewed journal.

  9. (tauqeer2018familialexudativevitreoretinopathy pages 7-7): Z. Tauqeer and Y. Yonekawa. Familial exudative vitreoretinopathy: pathophysiology, diagnosis, and management. Asia-Pacific Journal of Ophthalmology, 7:176–182, Apr 2018. URL: https://doi.org/10.22608/apo.201855, doi:10.22608/apo.201855. This article has 116 citations and is from a peer-reviewed journal.

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