Peters plus syndrome

Mendelian MONDO:0009856 Pathograph 18 Show in embeddings browser syndromic disease autosomal recessive disease congenital disorder of glycosylation

Peters plus syndrome (PTRPLS, Krause-Kivlin syndrome) is a rare autosomal recessive congenital disorder of glycosylation caused by biallelic loss-of-function variants in B3GLCT (formerly B3GALTL), which encodes beta-1,3-glucosyltransferase. B3GLCT performs the second step of a noncanonical endoplasmic-reticulum quality-control pathway: protein O-fucosyltransferase 2 (POFUT2) recognizes correctly folded thrombospondin type-1 repeats (TSRs) and attaches O-fucose, and B3GLCT then elongates it to the glucose-beta-1,3-fucose disaccharide. Unlike classical ER quality control, which tags unfolded protein, this pathway marks and stabilizes the folded state. Losing the terminal glucose destabilizes TSRs and impairs ER exit and secretion of a subset of the 49 predicted TSR-containing targets, most of which belong to the ADAMTS/ADAMTSL and thrombospondin families. Clinically the syndrome combines Peters anomaly and other anterior-segment eye anomalies with disproportionate rhizomelic short stature, brachydactyly with broad hands and feet, distinctive facies (exaggerated cupid's-bow upper lip, prominent forehead, hypertelorism), variable developmental delay or intellectual disability, and occasional cleft lip/palate and congenital heart defects. It is distinct from isolated Peters anomaly and from "Peters-plus-like" phenotypes, in neither of which biallelic loss-of-function B3GLCT variants are found.

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1
Inheritance
7
Pathophys.
24
Phenotypes
3
Gaps
18
Pathograph
1
Genes
2
Variants
7
Medical Actions
2
Differentials
2
Models
1
References
1
Deep Research
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Classifications

Harrison's Part
GENETICS ENVIRONMENT DISEASE
ICIMD (Inherited Metabolic Disorders)
o linked protein glycosylation
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Inheritance

1
Autosomal recessive inheritance HP:0000007
PTRPLS is autosomal recessive. Affected individuals carry biallelic pathogenic B3GLCT variants, or one pathogenic B3GLCT variant in trans with a contiguous 13q12.3 deletion that includes B3GLCT. The observed sibling recurrence risk at birth is lower than the theoretical 25% because of increased miscarriage and second- and third-trimester loss of affected fetuses.
Autosomal recessive inheritance
Show evidence (2 references)
PMID:20301637 SUPPORT Human Clinical
"PTRPLS is inherited in an autosomal recessive manner. If both parents are known to be heterozygous for a pathogenic variant involving B3GLCT, each sib of an affected individual has at conception a 25% chance of being affected"
GeneReviews establishes the autosomal recessive mode of inheritance and the recurrence risk.
PMID:16909395 SUPPORT Human Clinical
"we identified biallelic truncating mutations in the beta 1,3-galactosyltransferase-like gene (B3GALTL) in all 20 tested patients, showing that Peters Plus is a monogenic, primarily single-mutation syndrome"
The gene-discovery study documents biallelic (recessive) truncating variants in every tested proband.
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Discussions and Knowledge Gaps

3
Why does complete loss of b3glct in zebrafish produce no phenotype when the orthologous human loss of function causes a severe multisystem malformation syndrome, and what compensates?
HUMAN MODEL MISMATCH OPEN ptrpls_zebrafish_null_no_phenotype
Attached to
pathophysiology#Impaired ER Quality Control and Secretion of TSR-Containing Proteins
Zebrafish b3glcta/b3glctb double nulls have no detectable enzyme activity yet develop normally, while B3glct knockout mice reproduce much of the human syndrome and human biallelic loss is severe. The mismatch is not a failure of gene conservation - the zebrafish enzymes are catalytically equivalent to human B3GLCT - so it points to a species-specific compensatory route for TSR folding, or to a difference in the dosage sensitivity of the ADAMTS targets. Identifying that compensation would name a candidate therapeutic bypass of the human defect, so this is a mechanistically loaded rather than incidental discrepancy. It also means negative zebrafish results must not be treated as evidence against a proposed PTRPLS mechanism.
Proposed experiments
Characterize the zebrafish compensatory transcriptome
ptrpls_zebrafish_compensation_transcriptome
Follow up the 483 differentially regulated transcripts identified in b3glct-null embryos to test whether any encode an alternative glucosyltransferase or TSR chaperone that can substitute for b3glct, then test whether forced expression of the human ortholog of that factor rescues TSR secretion in B3GLCT-null human cells.
Supporting outcome
  • Identification of an upregulated factor whose human ortholog restores TSR secretion in B3GLCT-null human cells would support species-specific enzymatic or chaperone compensation.
Refuting outcome
  • Failure of any candidate to rescue human TSR secretion would argue that the difference lies in substrate dosage sensitivity rather than in a compensating factor.
Cross-species ADAMTS secretion comparison
ptrpls_cross_species_adamts_secretion
Quantify secretion of orthologous ADAMTS9 and ADAMTS20 proteins from B3GLCT-null human, mouse, and zebrafish cells to determine whether the species difference lies in the folding requirement of the substrate rather than in a compensating enzyme.
Supporting outcome
  • Preserved ADAMTS secretion from zebrafish nulls alongside impaired secretion from human and mouse nulls would localize the difference to the substrate rather than the pathway.
Refuting outcome
  • Equally impaired ADAMTS secretion across all three species would place the divergence downstream of secretion, in tissue-level tolerance of reduced ADAMTS activity.
Show evidence (2 references)
PMID:28926587 SUPPORT Model Organism
"The presented data show that both sequence and function of B3GLCT/b3glct genes is conserved in vertebrates. At the same time, complete b3glct deficiency in zebrafish appears to be inconsequential and possibly compensated for by a yet unknown mechanism."
States the mismatch and the compensation hypothesis explicitly.
PMID:31600785 SUPPORT Model Organism
"The mouse B3glct mutants developed craniofacial and skeletal abnormalities comparable to PTRPLS."
Contrasting mouse result that makes the zebrafish outcome a genuine cross-species discrepancy rather than a general model limitation.
Which of the 49 POFUT2/B3GLCT target proteins actually mediate each human PTRPLS manifestation, and why are only a subset dosage-sensitive to loss of the terminal glucose?
KNOWLEDGE GAP OPEN ptrpls_target_selectivity_gap
Attached to
pathophysiology#Reduced ADAMTS9 and ADAMTS20 Function in the Extracellular Matrix
Mouse genetics implicates ADAMTS20 and ADAMTS9 for hydrocephalus, white spotting, cleft palate, and eye defects, but the human phenotype includes features not explained by these two targets (rhizomelic short stature, brachydactyly, the characteristic facies, congenital heart and renal defects). The correspondence is not uniform in the other direction either: hydrocephalus, initially conspicuous as a mouse finding, is in fact documented in human PTRPLS fetuses at postmortem, so it appears to be a genuinely shared severe/prenatal feature that liveborn clinical series under-report - whereas white coat spotting has no human counterpart at all. Systematic mapping of which targets are under-secreted in patient cells and which tissues depend on each would turn the pathway model into a per-phenotype mechanism, and would clarify which apparent species differences are real versus ascertainment artifacts.
Show evidence (2 references)
PMID:31600785 SUPPORT Model Organism
"Previous studies suggested that O-linked fucose is essential for folding and secretion of POFUT2-modified proteins and that B3GLCT-mediated extension to the disaccharide is essential for only a subset of targets."
States the selective-dependency problem that this gap addresses.
PMID:25544610 SUPPORT In Vitro
"Although 49 putative targets are known, the function of the disaccharide and its role in PPS remain unexplored."
Frames the size of the target repertoire against which per-phenotype attribution is still missing.
Can the loss of glucose on properdin thrombospondin type-1 repeats be developed into a deployable clinical biomarker for Peters plus syndrome and for measuring response to any future therapy?
KNOWLEDGE GAP OPEN ptrpls_no_clinical_glycosylation_biomarker
Attached to
pathophysiology#Absent Glucose-beta-1,3-Fucose Disaccharide on Thrombospondin Type-1 Repeats
Unlike the N-glycosylation CDGs, PTRPLS has no routine screening assay - serum transferrin isoelectric focusing is normal - so diagnosis is entirely genotype-driven. The properdin glycoform assay is a validated research-grade biochemical readout of functional null status in patient material, but it has not been converted into an available clinical test. Without one there is no way to assay the functional consequence of a B3GLCT variant of uncertain significance, and no pharmacodynamic endpoint for a future therapy.
Show evidence (1 reference)
PMID:18199743 SUPPORT Human Clinical
"We have established a sensitive immunopurification-mass spectrometry method, using multiple reaction monitoring, to analyze Omicron-fucosyl glycans."
Describes the research assay that would need to be translated into a clinical test.
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Pathophysiology

7
B3GLCT Loss of Function
Biallelic loss-of-function variants in B3GLCT abolish or severely reduce beta-1,3-glucosyltransferase activity. The recurrent intronic splice-donor allele c.660+1G>A accounts for the majority of reported pathogenic alleles; frameshift, nonsense, other splice, and rare missense alleles complete the spectrum. In vitro assays show that PTRPLS-associated substitutions cause loss of catalytic activity and/or destabilize the protein, whereas substitutions found only in milder "Peters-plus-like" patients retain activity - evidence that it is specifically the loss of glucose transfer, not any B3GLCT sequence change, that produces the syndrome.
B3GLCT hgnc:20207 HUGO Gene Nomenclature Committee (hgnc) Relation: this pathophysiological event involves this gene This pathophysiological event involves B3GLCT (hgnc:20207). hgnc:20207 is a gene from the HUGO Gene Nomenclature Committee.
beta-1,3-glucosyltransferase activity GO:0046527 Gene Ontology (GO) Relation: this pathophysiological event involves this molecular function This pathophysiological event involves decreased beta-1,3-glucosyltransferase activity, annotated with glucosyltransferase activity (GO:0046527). GO:0046527 is a molecular function from the Gene Ontology. ↓ DECREASED
Downstream
Absent Glucose-beta-1,3-Fucose Disaccharide on Thrombospondin Type-1 Repeats Without B3GLCT activity the O-fucose added to TSRs by POFUT2 cannot be elongated to the Glc-beta1,3-Fuc disaccharide.
Show evidence (3 references)
PMID:16909395 SUPPORT Human Clinical
"After detection of a microdeletion by array-based comparative genomic hybridization, we identified biallelic truncating mutations in the beta 1,3-galactosyltransferase-like gene (B3GALTL) in all 20 tested patients"
Establishes biallelic truncating B3GLCT (B3GALTL) variants as the cause of Peters plus syndrome.
PMID:34058199 SUPPORT In Vitro
"Our results demonstrated that PTRPLS mutations caused loss of B3GLCT enzymatic activity and/or significantly reduced protein stability."
Functional assays confirm that PTRPLS alleles are loss-of-function at the level of enzyme activity or protein stability.
PMID:34058199 SUPPORT In Vitro
"Overall, our data supports the hypothesis that loss of glucose from B3GLCT substrate proteins is responsible for the defects observed in PTRPLS patients, but not for those observed in PTRPLS-like patients."
Ties the disease specifically to loss of the glucose transfer reaction and separates it from PTRPLS-like phenotypes.
Absent Glucose-beta-1,3-Fucose Disaccharide on Thrombospondin Type-1 Repeats
POFUT2 and B3GLCT act sequentially to add an O-linked glucose-beta-1,3-fucose disaccharide to properly folded thrombospondin type-1 repeats. In PTRPLS the pathway stalls after the first step, so TSRs on target glycoproteins carry only O-fucose. This was shown directly in patient-derived properdin, the reporter protein used to establish PTRPLS as a congenital disorder of glycosylation; loss of the disaccharide on properdin remains the only human biochemical readout of functional null status.
protein O-linked glycosylation via glucose GO:0180059 Gene Ontology (GO) Relation: this pathophysiological event involves this biological process This pathophysiological event involves decreased protein O-linked glycosylation via glucose (GO:0180059). GO:0180059 is a biological process from the Gene Ontology. ↓ DECREASED protein O-linked glycosylation GO:0006493 Gene Ontology (GO) Relation: this pathophysiological event involves this biological process This pathophysiological event involves decreased protein O-linked glycosylation (GO:0006493). GO:0006493 is a biological process from the Gene Ontology. ↓ DECREASED
Downstream
Impaired ER Quality Control and Secretion of TSR-Containing Proteins Fucose and glucose stabilize the folded TSR additively; without the glucose, folded TSRs are less stable and ER exit is less efficient.
Show evidence (2 references)
PMID:18199743 SUPPORT Human Clinical
"In contrast, properdin from heterozygous relatives and a healthy volunteer carried the Glc-beta1,3-Fuc-Omicron-disaccharide. These data firmly establish Peters Plus syndrome as a new congenital disorder of glycosylation."
Patient-versus-control comparison establishes the specific glycosylation lesion and classifies PTRPLS as a CDG.
PMID:25544610 SUPPORT In Vitro
"O-fucose is added to cysteine-rich domains called thrombospondin type 1 repeats (TSRs) by protein O-fucosyltransferase 2 (POFUT2) and is elongated with glucose by β3-glucosyltransferase (B3GLCT)."
States the two-enzyme sequential reaction that B3GLCT loss interrupts.
Impaired ER Quality Control and Secretion of TSR-Containing Proteins
POFUT2 and B3GLCT together constitute a noncanonical endoplasmic-reticulum quality-control mechanism. Where classical ER quality control identifies and tags unfolded protein, this pathway recognizes the FOLDED TSR cotranslationally and stabilizes it by glycosylation, marking it for ER exit. Loss of the terminal glucose therefore reduces the secretion efficiency of a subset of the 49 predicted TSR-modified proteins - a subset, not all of them, which is why PTRPLS is survivable while Pofut2-null mice are embryonic lethal. Nearly half of the targets are members of the ADAMTS superfamily, which act in the extracellular matrix.
protein folding in endoplasmic reticulum GO:0034975 Gene Ontology (GO) Relation: this pathophysiological event involves this biological process This pathophysiological event involves abnormal protein folding in endoplasmic reticulum (GO:0034975). GO:0034975 is a biological process from the Gene Ontology. ⚠ ABNORMAL protein secretion GO:0009306 Gene Ontology (GO) Relation: this pathophysiological event involves this biological process This pathophysiological event involves decreased protein secretion (GO:0009306). GO:0009306 is a biological process from the Gene Ontology. ↓ DECREASED
endoplasmic reticulum GO:0005783 Gene Ontology (GO) Relation: this pathophysiological event involves this cellular component This pathophysiological event involves endoplasmic reticulum (GO:0005783). GO:0005783 is a cellular component from the Gene Ontology.
Downstream
Reduced ADAMTS9 and ADAMTS20 Function in the Extracellular Matrix ADAMTS9 and ADAMTS20 are among the TSR targets most sensitive to loss of the disaccharide, and mouse genetics attributes distinct PTRPLS-like defects to each.
Show evidence (3 references)
PMID:25544610 SUPPORT In Vitro
"While known ER quality-control machinery rely on identifying and tagging unfolded proteins, we find that POFUT2 and B3GLCT mediate a noncanonical ER quality-control mechanism that recognizes folded TSRs and stabilizes them by glycosylation."
Defines the noncanonical, folded-state-recognizing quality-control mechanism that B3GLCT loss disrupts.
PMID:25544610 SUPPORT In Vitro
"Here we show that while POFUT2 is required for secretion of all targets tested, B3GLCT only affects the secretion of a subset, consistent with the observation that B3GLCT mutant phenotypes in PPS patients are less severe than embryonic lethal phenotypes of Pofut2-null mice."
Explains the selective, sub-lethal character of the human phenotype: only some TSR targets depend on the B3GLCT step.
PMID:31600785 SUPPORT Model Organism
"Forty-nine proteins are predicted to be modified by POFUT2, and nearly half are members of the ADAMTS superfamily."
Quantifies the target repertoire and identifies ADAMTS proteins as the dominant substrate class.
Reduced ADAMTS9 and ADAMTS20 Function in the Extracellular Matrix
Under-secretion of TSR-bearing ADAMTS metalloproteinases degrades extracellular-matrix remodelling during organogenesis. In B3glct knockout mice the pattern is target-specific: hydrocephalus and white spotting track with loss of ADAMTS20, eye abnormalities with partial reduction of ADAMTS9, and cleft palate with the combination of both.
extracellular matrix organization GO:0030198 Gene Ontology (GO) Relation: this pathophysiological event involves this biological process This pathophysiological event involves abnormal extracellular matrix organization (GO:0030198). GO:0030198 is a biological process from the Gene Ontology. ⚠ ABNORMAL
Downstream
Anterior Segment Dysgenesis Reduced ADAMTS9 activity is the mouse-genetic correlate of the ocular defects; the intervening steps between reduced ADAMTS9 secretion and failure of anterior-segment separation are not established.
Impaired Craniofacial and Endochondral Skeletal Growth B3glct knockout mice reproduce the craniofacial and skeletal arm of the human phenotype, but the specific TSR targets mediating growth-plate and craniofacial effects have not been resolved.
Failure of Palatal Shelf Fusion Cleft palate in the mouse model requires combined ADAMTS20 loss and partial ADAMTS9 reduction.
Show evidence (1 reference)
PMID:31600785 SUPPORT Model Organism
"We provide strong genetic and biochemical evidence that hydrocephalus and white spotting in B3glct mutants resulted from loss of ADAMTS20, eye abnormalities from partial reduction of ADAMTS9 and cleft palate from loss of ADAMTS20 and partially reduced ADAMTS9 function."
Assigns individual PTRPLS-like malformations to specific ADAMTS effectors.
Anterior Segment Dysgenesis
Defective remodelling of the developing anterior eye segment produces Peters anomaly: failure to separate the lens vesicle and/or iris from the surface ectoderm-derived cornea, leaving posterior corneal (Descemet membrane and endothelium) defects with iridocorneal and sometimes keratolenticular adhesions. Deep ocular phenotyping in PTRPLS most often shows an avascular paracentral ring opacity caused by iridocorneal adhesion, with relative central clearing over an area of posterior stromal thinning; a large vascularized central opacity is the less common alternative pattern. Periocular neural-crest-derived mesenchyme populates these structures, and abnormal neural crest development was the leading pre-molecular hypothesis for the syndrome.
periocular neural crest cell CL:0011012 Cell Ontology (CL) Relation: this pathophysiological event involves this cell type This pathophysiological event involves periocular neural crest cell, annotated with neural crest cell (CL:0011012). CL:0011012 is a cell type from the Cell Ontology. corneal endothelial cell CL:0000132 Cell Ontology (CL) Relation: this pathophysiological event involves this cell type This pathophysiological event involves corneal endothelial cell (CL:0000132). CL:0000132 is a cell type from the Cell Ontology. corneal stromal keratocyte CL:0002363 Cell Ontology (CL) Relation: this pathophysiological event involves this cell type This pathophysiological event involves corneal stromal keratocyte, annotated with keratocyte (CL:0002363). CL:0002363 is a cell type from the Cell Ontology.
cornea development in camera-type eye GO:0061303 Gene Ontology (GO) Relation: this pathophysiological event involves this biological process This pathophysiological event involves abnormal cornea development in camera-type eye (GO:0061303). GO:0061303 is a biological process from the Gene Ontology. ⚠ ABNORMAL neural crest cell development GO:0014032 Gene Ontology (GO) Relation: this pathophysiological event involves this biological process This pathophysiological event involves abnormal neural crest cell development (GO:0014032). GO:0014032 is a biological process from the Gene Ontology. ⚠ ABNORMAL
anterior segment of eyeball UBERON:0001801 Uberon multi-species anatomy ontology (UBERON) Relation: this pathophysiological event occurs in this anatomical location This pathophysiological event occurs in anterior segment of eyeball (UBERON:0001801). UBERON:0001801 is an anatomical location from the Uberon multi-species anatomy ontology.
Show evidence (3 references)
PMID:34629439 SUPPORT Human Clinical
"The paracentral opacity is due to iridocorneal adhesion and the relative central clearing associated with posterior stromal thinning."
Deep phenotyping identifies the anatomical lesion underlying the corneal opacity in PTRPLS.
PMID:35170016 SUPPORT Human Clinical
"Peters' anomaly (PA) is a rare anterior segment dysgenesis characterized by central corneal opacity and irido-lenticulo-corneal adhesions."
Defines the anatomical lesion of Peters anomaly that this node models.
PMID:12119218 SUPPORT Human Clinical
"The etiology is unknown, but may involve abnormal neural crest development."
Records the pre-molecular neural-crest hypothesis for the anterior-segment lesion; it remains a plausible cellular substrate but has not been directly demonstrated for B3GLCT loss.
Impaired Craniofacial and Endochondral Skeletal Growth
Disrupted extracellular-matrix remodelling in the growth plate and craniofacial skeleton produces disproportionate, rhizomelic short stature with brachydactyly and broad hands and feet, and the characteristic facial gestalt. B3glct knockout mice reproduce craniofacial and skeletal abnormalities comparable to the human syndrome.
growth plate chondrocyte CL:0000138 Cell Ontology (CL) Relation: this pathophysiological event involves this cell type This pathophysiological event involves growth plate chondrocyte, annotated with chondrocyte (CL:0000138). CL:0000138 is a cell type from the Cell Ontology.
endochondral bone growth GO:0003416 Gene Ontology (GO) Relation: this pathophysiological event involves this biological process This pathophysiological event involves decreased endochondral bone growth (GO:0003416). GO:0003416 is a biological process from the Gene Ontology. ↓ DECREASED skeletal system development GO:0001501 Gene Ontology (GO) Relation: this pathophysiological event involves this biological process This pathophysiological event involves abnormal skeletal system development (GO:0001501). GO:0001501 is a biological process from the Gene Ontology. ⚠ ABNORMAL limb development GO:0060173 Gene Ontology (GO) Relation: this pathophysiological event involves this biological process This pathophysiological event involves abnormal limb development (GO:0060173). GO:0060173 is a biological process from the Gene Ontology. ⚠ ABNORMAL
growth plate UBERON:0002516 Uberon multi-species anatomy ontology (UBERON) Relation: this pathophysiological event occurs in this anatomical location This pathophysiological event occurs in growth plate, annotated with epiphyseal plate (UBERON:0002516). UBERON:0002516 is an anatomical location from the Uberon multi-species anatomy ontology. skeletal system UBERON:0001434 Uberon multi-species anatomy ontology (UBERON) Relation: this pathophysiological event occurs in this anatomical location This pathophysiological event occurs in skeletal system (UBERON:0001434). UBERON:0001434 is an anatomical location from the Uberon multi-species anatomy ontology.
Show evidence (2 references)
PMID:31600785 SUPPORT Model Organism
"The mouse B3glct mutants developed craniofacial and skeletal abnormalities comparable to PTRPLS."
Animal-model support for the skeletal and craniofacial arm of the pathophysiology.
PMID:34058199 SUPPORT Other
"patients have multiple structural anomalies, including Peters anomaly of the eye (anterior segment dysgenesis), disproportionate short stature, brachydactyly, dysmorphic facial features, developmental delay"
Confirms the skeletal-growth and craniofacial manifestations in patients. Classified OTHER because the quoted sentence is this in vitro study's restatement of the established human clinical description, not new patient data that the paper itself reports.
Failure of Palatal Shelf Fusion
A subset of individuals develop cleft lip and/or palate. In the B3glct mouse, cleft palate arises only when ADAMTS20 is lost and ADAMTS9 is partially reduced, indicating that palatal shelf fusion is a combined-dosage-sensitive readout of the pathway.
roof of mouth development GO:0060021 Gene Ontology (GO) Relation: this pathophysiological event involves this biological process This pathophysiological event involves abnormal roof of mouth development (GO:0060021). GO:0060021 is a biological process from the Gene Ontology. ⚠ ABNORMAL
secondary palate UBERON:0001716 Uberon multi-species anatomy ontology (UBERON) Relation: this pathophysiological event occurs in this anatomical location This pathophysiological event occurs in secondary palate (UBERON:0001716). UBERON:0001716 is an anatomical location from the Uberon multi-species anatomy ontology.
Show evidence (2 references)
PMID:31600785 SUPPORT Model Organism
"cleft palate from loss of ADAMTS20 and partially reduced ADAMTS9 function"
Mechanistic attribution of clefting to combined ADAMTS20/ADAMTS9 deficit.
PMID:18199743 SUPPORT Human Clinical
"Peters Plus syndrome is an autosomal recessive disorder characterized by anterior eye chamber defects, disproportionate short stature, developmental delay, and cleft lip and/or palate."
Confirms orofacial clefting as part of the human clinical definition.
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Pathograph

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

24
Cardiovascular 1
Congenital Heart Defect OCCASIONAL Abnormal heart morphology HP:0001627 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Abnormal heart morphology (HP:0001627). HP:0001627 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:20301637 SUPPORT Human Clinical
"and, occasionally, cleft lip/palate and congenital heart defects"
GeneReviews describes congenital heart defects as an occasional finding, which maps to the OCCASIONAL frequency band (5-29%) in the project's prose-to-enum mapping table.
Eye 7
Peters Anomaly HP:0000659 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Peters anomaly (HP:0000659). HP:0000659 is a phenotype from the Human Phenotype Ontology.
Show evidence (2 references)
PMID:20301637 SUPPORT Human Clinical
"Peters plus syndrome (PTRPLS) is characterized by congenital eye anomalies, particularly Peters anomaly, which results in varying degrees of corneal opacity and lens anomalies"
GeneReviews identifies Peters anomaly as the characteristic congenital eye anomaly of the syndrome.
PMID:34629439 SUPPORT Human Clinical
"The most common ocular phenotype seen in Peters-plus syndrome is an avascular paracentral ring opacity with relative central clearing. A different phenotype with a large vascularized corneal opacity may also be observed."
Case series characterizing the two ocular sub-phenotypes of PTRPLS.
Corneal Opacity HP:0007957 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Corneal opacity (HP:0007957). HP:0007957 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:20301637 SUPPORT Human Clinical
"which results in varying degrees of corneal opacity and lens anomalies, as well as an increased risk of glaucoma"
GeneReviews documents corneal opacity as a direct consequence of the Peters anomaly.
Glaucoma HP:0000501 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Glaucoma (HP:0000501). HP:0000501 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:20301637 SUPPORT Human Clinical
"as well as an increased risk of glaucoma"
GeneReviews records increased glaucoma risk as part of the ocular phenotype.
Microphthalmia HP:0000568 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Microphthalmia (HP:0000568). HP:0000568 is a phenotype from the Human Phenotype Ontology.
Show evidence (2 references)
PMID:20301637 SUPPORT Human Clinical
"Other eye findings can include posterior segment abnormalities (including retinal and/or optic nerve coloboma) and microphthalmia."
GeneReviews lists microphthalmia among the additional ocular findings.
PMID:15912477 SUPPORT Human Clinical
"Ultrasound examination revealed microphthalmia and hyperechogenicity of the anterior part of the eye with a central defect"
Documents microphthalmia detected on prenatal ultrasound in a subsequently autopsy-confirmed case.
Coloboma HP:0000589 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Coloboma (HP:0000589). HP:0000589 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:20301637 SUPPORT Human Clinical
"Other eye findings can include posterior segment abnormalities (including retinal and/or optic nerve coloboma)"
GeneReviews documents retinal and optic nerve coloboma in PTRPLS.
Visual Impairment HP:0000505 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Visual impairment (HP:0000505). HP:0000505 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:31600785 SUPPORT Other
"it results in corneal opacity, with severe visual impairment and other eye complications"
Identifies visual impairment as the functional outcome of the Peters anomaly. Classified OTHER because the sentence is this mouse study's restatement of the established human clinical description rather than its own data.
Hypertelorism HP:0000316 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Hypertelorism (HP:0000316). HP:0000316 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:31600785 SUPPORT Other
"characterized by defects in eye development, prominent forehead, hypertelorism, short stature and brachydactyly"
Hypertelorism listed among the defining clinical features. Classified OTHER because the quoted sentence is this mouse study's restatement of the established human clinical description rather than its own patient or model data.
Head and Neck 2
Prominent Forehead HP:0011220 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Prominent forehead (HP:0011220). HP:0011220 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:31600785 SUPPORT Other
"characterized by defects in eye development, prominent forehead, hypertelorism, short stature and brachydactyly"
Prominent forehead listed among the defining clinical features. Classified OTHER because the quoted sentence is this mouse study's restatement of the established human clinical description rather than its own patient or model data.
Cleft Palate OCCASIONAL HP:0000175 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Cleft palate (HP:0000175). HP:0000175 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:20301637 SUPPORT Human Clinical
"and, occasionally, cleft lip/palate and congenital heart defects"
GeneReviews describes cleft lip/palate as an occasional finding, which maps to the OCCASIONAL frequency band (5-29%) in the project's prose-to-enum mapping table.
Limbs 2
Brachydactyly HP:0001156 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Brachydactyly (HP:0001156). HP:0001156 is a phenotype from the Human Phenotype Ontology.
Show evidence (2 references)
PMID:34058199 SUPPORT Other
"Peters anomaly of the eye (anterior segment dysgenesis), disproportionate short stature, brachydactyly, dysmorphic facial features, developmental delay"
Lists brachydactyly among the core clinical features of PTRPLS. Classified OTHER because the quoted sentence is this in vitro study's restatement of the established human clinical description rather than new patient data.
PMID:31600785 SUPPORT Other
"characterized by defects in eye development, prominent forehead, hypertelorism, short stature and brachydactyly"
Independent listing of brachydactyly in the clinical definition. Classified OTHER because the quoted sentence is this mouse study's restatement of the established human clinical description, not data from the mouse model or from patients it studied.
Broad Hands Broad palm HP:0001169 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Broad palm (HP:0001169). HP:0001169 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:20301637 SUPPORT Human Clinical
"rhizomelic shortening of the limbs with broad hands and feet"
GeneReviews documents broad hands as part of the skeletal phenotype.
Nervous System 4
Hydrocephalus HP:0000238 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Hydrocephalus (HP:0000238). HP:0000238 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:31600785 SUPPORT Other
"postmortem analysis of PTRPLS fetuses identified additional abnormalities including growth retardation, hydrocephalus, agenesis of the corpus callosum, Dandy-Walker cyst and gut anomalies"
Documents hydrocephalus in human PTRPLS fetuses at postmortem. Classified OTHER because this mouse paper is citing a separate human postmortem series rather than reporting the finding itself.
Agenesis of the Corpus Callosum Agenesis of corpus callosum HP:0001274 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Agenesis of corpus callosum (HP:0001274). HP:0001274 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:31600785 SUPPORT Other
"postmortem analysis of PTRPLS fetuses identified additional abnormalities including growth retardation, hydrocephalus, agenesis of the corpus callosum, Dandy-Walker cyst and gut anomalies"
Documents agenesis of the corpus callosum in human PTRPLS fetuses. Classified OTHER because this mouse paper is citing a separate human postmortem series rather than reporting the finding itself.
Developmental Delay Global developmental delay HP:0001263 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Global developmental delay (HP:0001263). HP:0001263 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:20301637 SUPPORT Human Clinical
"variable developmental delay / intellectual disability, typical facial features"
GeneReviews documents variable developmental delay as a core non-ophthalmologic finding.
Intellectual Disability HP:0001249 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Intellectual disability (HP:0001249). HP:0001249 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:20301637 SUPPORT Human Clinical
"variable developmental delay / intellectual disability"
GeneReviews records intellectual disability as a variable manifestation.
Growth 2
Disproportionate Short Stature HP:0003498 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Disproportionate short stature (HP:0003498). HP:0003498 is a phenotype from the Human Phenotype Ontology.
Show evidence (2 references)
PMID:20301637 SUPPORT Human Clinical
"Additional non-ophthalmologic findings include short stature with rhizomelic shortening of the limbs with broad hands and feet"
GeneReviews establishes disproportionate short stature with rhizomelic limb shortening.
PMID:16909395 SUPPORT Human Clinical
"Peters Plus syndrome is an autosomal recessive disorder characterized by anterior eye-chamber abnormalities, disproportionate short stature, and developmental delay."
Independent confirmation of disproportionate short stature as a defining feature.
Rhizomelic Limb Shortening Rhizomelia HP:0008905 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Rhizomelia (HP:0008905). HP:0008905 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:20301637 SUPPORT Human Clinical
"short stature with rhizomelic shortening of the limbs"
GeneReviews specifies the rhizomelic pattern of limb shortening.
Other 6
Lens Anomalies Abnormal lens morphology HP:0000517 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Abnormal lens morphology (HP:0000517). HP:0000517 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:20301637 SUPPORT Human Clinical
"which results in varying degrees of corneal opacity and lens anomalies"
GeneReviews lists lens anomalies among the core ocular findings.
Dandy-Walker Malformation HP:0001305 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Dandy-Walker malformation (HP:0001305). HP:0001305 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:31600785 SUPPORT Other
"postmortem analysis of PTRPLS fetuses identified additional abnormalities including growth retardation, hydrocephalus, agenesis of the corpus callosum, Dandy-Walker cyst and gut anomalies"
Documents a Dandy-Walker cyst in human PTRPLS fetuses. Classified OTHER because this mouse paper is citing a separate human postmortem series rather than reporting the finding itself.
Broad Feet Broad foot HP:0001769 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Broad foot (HP:0001769). HP:0001769 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:20301637 SUPPORT Human Clinical
"rhizomelic shortening of the limbs with broad hands and feet"
GeneReviews documents broad feet as part of the skeletal phenotype.
Exaggerated Cupid's Bow Upper Lip HP:0002263 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Exaggerated cupid's bow (HP:0002263). HP:0002263 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:12119218 SUPPORT Human Clinical
"Major symptoms are extremely variable anterior chamber anomalies, cupid bow of the upper lip, cleft lip and palate, short stature, broad hands and feet, and variable mental delay."
Clinical review lists the cupid's-bow upper lip among the major manifestations.
Cleft Lip OCCASIONAL Cleft upper lip HP:0000204 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Cleft upper lip (HP:0000204). HP:0000204 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:20301637 SUPPORT Human Clinical
"and, occasionally, cleft lip/palate and congenital heart defects"
GeneReviews describes cleft lip/palate as an occasional finding, which maps to the OCCASIONAL frequency band (5-29%) in the project's prose-to-enum mapping table.
Renal Anomalies Multicystic kidney dysplasia HP:0000003 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Multicystic kidney dysplasia (HP:0000003). HP:0000003 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:15912477 SUPPORT Human Clinical
"short limbs with broad extremities and unilateral multicystic kidney"
Documents unilateral multicystic dysplastic kidney in an autopsy-confirmed case of Peters plus syndrome.
🧬

Genetic Associations

1
B3GLCT
Gene: B3GLCT hgnc:20207 HUGO Gene Nomenclature Committee (hgnc) Relation: this disease-associated gene is this gene This disease-associated gene is B3GLCT (hgnc:20207). hgnc:20207 is a gene from the HUGO Gene Nomenclature Committee. relationship_type: CAUSATIVE variant_origin: GERMLINE
Show evidence (5 references)
PMID:16909395 SUPPORT Human Clinical
"we identified biallelic truncating mutations in the beta 1,3-galactosyltransferase-like gene (B3GALTL) in all 20 tested patients"
Establishes B3GLCT (B3GALTL) as the single causal gene.
PMID:23889335 SUPPORT Human Clinical
"Consistent with previous reports, the c.660+1G>A mutation was the most common mutation identified, seen in eight of the nine patients and accounting for 55% of pathogenic alleles in this study and 69% of all reported pathogenic alleles"
Quantifies the dominance of the recurrent c.660+1G>A splice allele in the mutation spectrum.
PMID:18798333 SUPPORT Human Clinical
"Mutations in B3GALTL were identified in all four patients with typical Peters Plus syndrome, while no mutations were found in the remaining four patients that demonstrated some but not all characteristic features of the syndrome."
Shows that B3GLCT variants segregate with the complete syndrome and not with partial phenotypes.
+ 2 more references
🔬

Variants

2
B3GLCT c.660+1G>A Pathogenic
Gene: B3GLCT hgnc:20207 HUGO Gene Nomenclature Committee (hgnc) Relation: this variant is in this gene This variant is in B3GLCT (hgnc:20207). hgnc:20207 is a gene from the HUGO Gene Nomenclature Committee.
Recurrent intronic splice-donor variant (rs80338851), the single most common pathogenic B3GLCT allele; it accounts for roughly two-thirds to three-quarters of reported pathogenic alleles across cohorts and is found homozygously or in trans with a rarer second allele.
Show evidence (2 references)
PMID:23889335 SUPPORT Human Clinical
"while two patients were homozygous for this mutation, the majority had a second rare pathogenic allele"
Describes the typical allelic configuration involving the recurrent splice-donor variant.
PMID:18798333 SUPPORT Human Clinical
"The previously reported common mutation, c.660 + 1G > A, accounted for 75% of the mutant alleles in our Peters Plus syndrome population."
Independent cohort quantifying the allele frequency of the recurrent splice variant.
B3GLCT c.755delC (p.Thr252fs) Pathogenic
Gene: B3GLCT hgnc:20207 HUGO Gene Nomenclature Committee (hgnc) Relation: this variant is in this gene This variant is in B3GLCT (hgnc:20207). hgnc:20207 is a gene from the HUGO Gene Nomenclature Committee.
Frameshift variant in exon 9, first reported in 2019 in a newborn who was compound heterozygous for it and the recurrent c.660+1G>A allele. Illustrates the typical "one recurrent splice allele plus one private truncating allele" genotype.
Show evidence (1 reference)
PMID:31795264 SUPPORT Human Clinical
"helped us find two compound heterozygous variants of the B3GLCT gene, of which c.660+1G>A (rs80338851) was previously associated with the phenotype of Peters plus syndrome (PPS), while the second, NM_194318.3:c.755delC (p.T252fs), in exon 9 of the same gene was noted for the first time"
Reports the novel frameshift allele and the compound-heterozygous configuration with the recurrent splice variant.
💊

Medical Actions

7
Multidisciplinary Supportive Care
Category: Therapeutic Action: multidisciplinary supportive careNCI Thesaurus (NCIT) Relation: this treatment is this clinical intervention This treatment is multidisciplinary supportive care, annotated with Supportive Care (NCIT:C15747). NCIT:C15747 is a clinical intervention from the NCI Thesaurus. Ontology label: Supportive Care NCIT:C15747
There is no disease-modifying therapy - no B3GLCT replacement, substrate, chaperone, gene, or RNA therapy exists. Management is supportive and multidisciplinary, coordinating ophthalmology, orthopedics, rehabilitation therapies, educational support, a cleft lip/palate team, and social services including planning the transition from pediatric to adult care.
Show evidence (1 reference)
PMID:20301637 SUPPORT Human Clinical
"Multidisciplinary care by specialists in relevant fields including ophthalmology to manage eye anomalies; low vision services as needed; orthopedics, physical therapy, and occupational therapy to determine need for adaptive devices to address mobility and fine motor needs; educational support..."
GeneReviews management recommendation defining the supportive-care model.
Ophthalmologic Surgical Management
Category: Therapeutic Action: ophthalmologic surgical procedureNCI Thesaurus (NCIT) Relation: this treatment is this clinical intervention This treatment is ophthalmologic surgical procedure (NCIT:C15331). NCIT:C15331 is a clinical intervention from the NCI Thesaurus. Ontology label: Ophthalmologic Surgical Procedure NCIT:C15331
Surgical management of the anterior-segment anomaly, which may include penetrating keratoplasty or keratoprosthesis for visually significant opacity, lensectomy, and glaucoma procedures. Decisions are individualized: severe bilateral dysgenesis, glaucoma, graft failure, and retinal complications can limit the benefit, and surgery is sometimes deliberately deferred.
Target Phenotypes: Corneal opacity HP:0007957 Human Phenotype Ontology (HP) Relation: this treatment targets this phenotype This treatment targets Corneal opacity (HP:0007957). HP:0007957 is a phenotype from the Human Phenotype Ontology. Glaucoma HP:0000501 Human Phenotype Ontology (HP) Relation: this treatment targets this phenotype This treatment targets Glaucoma (HP:0000501). HP:0000501 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:20301637 SUPPORT Human Clinical
"Multidisciplinary care by specialists in relevant fields including ophthalmology to manage eye anomalies; low vision services as needed"
GeneReviews assigns management of the eye anomalies to ophthalmology, with low-vision services as adjunct.
Ophthalmologic Surveillance for Glaucoma
Category: Monitoring Action: ophthalmologic surveillanceNCI Thesaurus (NCIT) Relation: this treatment is this clinical intervention This treatment is ophthalmologic surveillance, annotated with Eye Examination (NCIT:C38060). NCIT:C38060 is a clinical intervention from the NCI Thesaurus. Ontology label: Eye Examination NCIT:C38060
Because glaucoma can develop at any age and threatens residual vision, GeneReviews recommends intraocular-pressure and ophthalmologic surveillance in early infancy, again at three and six months of age, and at least every six months thereafter. Early infancy is also the critical window for detecting and treating deprivation amblyopia.
Show evidence (1 reference)
PMID:20301637 SUPPORT Human Clinical
"monitor emergence of new ophthalmologic manifestations including glaucoma in early infancy, then at age three months and age six months, and a minimum of every six months thereafter"
GeneReviews surveillance schedule for glaucoma.
Physical and Occupational Therapy
Category: Therapeutic Action: physical therapyNCI Thesaurus (NCIT) Relation: this treatment is this clinical intervention This treatment is physical therapy (NCIT:C15302). NCIT:C15302 is a clinical intervention from the NCI Thesaurus. Ontology label: Physical Therapy NCIT:C15302
Physical and occupational therapy, coordinated with orthopedics, to address mobility and fine-motor needs arising from short stature, rhizomelia, and hand anomalies, and to determine the need for adaptive devices.
Show evidence (1 reference)
PMID:20301637 SUPPORT Human Clinical
"orthopedics, physical therapy, and occupational therapy to determine need for adaptive devices to address mobility and fine motor needs"
GeneReviews recommendation for rehabilitation therapy.
Cleft Lip and Palate Repair
Category: Therapeutic Action: surgical procedureNCI Thesaurus (NCIT) Relation: this treatment is this clinical intervention This treatment is surgical procedure (NCIT:C15329). NCIT:C15329 is a clinical intervention from the NCI Thesaurus. Ontology label: Surgical Procedure NCIT:C15329
Surgical repair and longitudinal management of cleft lip and/or palate by a dedicated cleft team, when clefting is present, together with feeding, speech, dental, and audiology support.
Target Phenotypes: Cleft palate HP:0000175 Human Phenotype Ontology (HP) Relation: this treatment targets this phenotype This treatment targets Cleft palate (HP:0000175). HP:0000175 is a phenotype from the Human Phenotype Ontology. Cleft upper lip HP:0000204 Human Phenotype Ontology (HP) Relation: this treatment targets this phenotype This treatment targets Cleft upper lip (HP:0000204). HP:0000204 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:20301637 SUPPORT Human Clinical
"cleft lip/palate team"
GeneReviews assigns cleft management to a dedicated multidisciplinary team.
Educational and Developmental Support
Category: Therapeutic Action: educational and developmental supportNCI Thesaurus (NCIT) Relation: this treatment is this clinical intervention This treatment is educational and developmental support, annotated with Supportive Care (NCIT:C15747). NCIT:C15747 is a clinical intervention from the NCI Thesaurus. Ontology label: Supportive Care NCIT:C15747
Individualized educational support and early-intervention services for developmental delay and/or intellectual disability, with monitoring of educational, neurobehavioral, and musculoskeletal needs over time.
Target Phenotypes: Global developmental delay HP:0001263 Human Phenotype Ontology (HP) Relation: this treatment targets this phenotype This treatment targets Global developmental delay (HP:0001263). HP:0001263 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:20301637 SUPPORT Human Clinical
"Monitor the individual's response to supportive care (including educational, neurobehavioral, and musculoskeletal needs)"
GeneReviews surveillance recommendation covering the developmental and educational domain.
Genetic Counseling
Category: Counseling / Informational Action: genetic counselingNCI Thesaurus (NCIT) Relation: this treatment is this clinical intervention This treatment is genetic counseling (NCIT:C15240). NCIT:C15240 is a clinical intervention from the NCI Thesaurus. Ontology label: Genetic Counseling NCIT:C15240
Counseling on autosomal recessive recurrence risk. Once the familial B3GLCT variants are known, carrier testing for at-risk relatives and prenatal or preimplantation genetic testing are available. Counseling should note that the observed sibling risk at birth is below the theoretical 25% because of increased fetal loss.
Show evidence (1 reference)
PMID:20301637 SUPPORT Human Clinical
"Once the pathogenic variants involving B3GLCT have been identified in an affected family member, carrier testing for at-risk relatives and prenatal/preimplantation genetic testing for PTRPLS are possible."
GeneReviews genetic-counseling recommendation.
🔬

Diagnosis

2
B3GLCT Molecular Genetic Testing
The diagnosis is established molecularly in a proband with suggestive clinical findings by identifying biallelic pathogenic B3GLCT variants, or one pathogenic variant in trans with a 13q12.3 contiguous gene deletion encompassing B3GLCT. Sequencing alone can miss the deletion allele, so copy-number analysis of 13q12.3 should accompany sequencing.
Show evidence (2 references)
PMID:20301637 SUPPORT Human Clinical
"The diagnosis of PTRPLS is established in a proband with suggestive findings and either biallelic pathogenic variants in B3GLCT or compound heterozygosity for one pathogenic variant in B3GLCT and a contiguous gene deletion of 13q12.3 that includes B3GLCT identified by molecular genetic testing."
GeneReviews diagnostic criterion.
PMID:35170016 SUPPORT Human Clinical
"Causative genetic defects involving 12 genes and CNVs were identified for 1/3 of patients."
Reports diagnostic yield across the Peters anomaly spectrum using combined array, exome, genome, and panel testing. This is spectrum-wide yield, not PTRPLS test sensitivity, so it is recorded as partial support.
Prenatal Ultrasound Recognition
The syndrome can be suspected prenatally on the combination of microphthalmia with an echogenic anterior eye defect, short limbs with broad extremities, micrognathia and long philtrum, and renal anomalies. Corneal and anterior-segment findings are nonetheless hard to detect prenatally, so a normal scan does not exclude the diagnosis.
Show evidence (1 reference)
PMID:15912477 SUPPORT Human Clinical
"Ultrasound examination revealed microphthalmia and hyperechogenicity of the anterior part of the eye with a central defect, micrognathia and long philtrum, short limbs with broad extremities and unilateral multicystic kidney."
Documents the prenatal sonographic constellation in an autopsy-confirmed case.
📈

Progression

2
Prenatal
The molecular defect acts during embryogenesis, so the malformations are congenital rather than acquired. Affected pregnancies carry an increased risk of miscarriage and of second- and third-trimester fetal loss, so the observed proportion of affected liveborn siblings is below the theoretical 25% recurrence risk.
Show evidence (1 reference)
PMID:20301637 SUPPORT Human Clinical
"However, at birth the risk to sibs of a proband of being affected is less than 25% because there is an increased chance for miscarriages and second- and third-trimester loss of affected fetuses."
GeneReviews documents excess prenatal lethality as a feature of the natural history.
Infancy and childhood
Structural lesions are congenital and largely non-progressive, but their consequences evolve. Early infancy is the critical window for visual-axis clearing and amblyopia prevention; glaucoma may emerge at any point and requires the GeneReviews surveillance schedule; feeding, speech, dental, and hearing consequences of clefting change with age; and short stature and developmental limitations become more apparent as developmental demands increase.
Show evidence (1 reference)
PMID:20301637 SUPPORT Human Clinical
"monitor emergence of new ophthalmologic manifestations including glaucoma in early infancy, then at age three months and age six months, and a minimum of every six months thereafter"
The surveillance schedule reflects the expectation that new ophthalmologic manifestations emerge over the course of infancy and childhood.
📊

Prevalence

1
Worldwide
Unknown Ultra Rare
No robust PTRPLS-specific prevalence or incidence estimate exists; the literature consistently describes it only qualitatively as a very rare subtype of anterior segment dysgenesis. The population figure of 2.2-3.1 per 100,000 births that appears in recent literature applies to the broader Peters anomaly spectrum and must NOT be relabelled as a Peters plus syndrome rate. Orphanet (ORPHA:709) would be the natural structured source but no ORPHA cache record could be generated in this repository.
Show evidence (1 reference)
PMID:31795264 SUPPORT Human Clinical
"PPS, a very rare subtype of ASD, is a glycosylation disorder"
Supports only the qualitative rarity band; no quantitative rate is asserted anywhere in the reviewed literature.
🔀

Differential Diagnoses

2

Conditions with similar clinical presentations that must be differentiated from Peters plus syndrome:

Isolated Peters anomaly
Overlapping Features Peters anomaly occurring without the systemic features of PTRPLS. This is the single most important distinction for this entry: isolated Peters anomaly is a genetically distinct anterior-segment dysgenesis, and B3GLCT variants are consistently absent in it. Screening of 55 individuals with PTRPLS-like phenotypes or isolated Peters anomaly identified no B3GLCT variants, and in the largest Peters anomaly cohort reported the leading gene for isolated disease is PAX6 rather than B3GLCT.
Distinguishing Features
  • Absence of disproportionate rhizomelic short stature, brachydactyly, and broad hands and feet
  • Absence of the characteristic facies (exaggerated cupid's-bow upper lip, prominent forehead, hypertelorism)
  • Absence of cleft lip and/or palate and of developmental delay
  • Absence of biallelic loss-of-function B3GLCT variants
  • Often unilateral and milder ocular disease, whereas PTRPLS ocular involvement is typically bilateral
  • Associated instead with PAX6, PITX2, PITX3, FOXE3, FOXC1, CYP1B1, and SOX2 variants
Show evidence (3 references)
PMID:23889335 SUPPORT Human Clinical
"We also report the absence of B3GALTL mutations in 55 cases of PPS-like phenotypes or isolated Peters anomaly, further establishing the strong association of B3GALTL mutations with classic PPS only."
Direct cohort evidence that B3GLCT is not implicated in isolated Peters anomaly, separating it from PTRPLS.
PMID:35170016 SUPPORT Human Clinical
"Several genes are involved in syndromic or isolated PA (B3GLCT, PAX6, PITX3, FOXE3, CYP1B1)."
Enumerates the genetically distinct causes of Peters anomaly outside the B3GLCT syndromic entity.
PMID:35170016 SUPPORT Human Clinical
"Unsurprisingly, B3GLCT and PAX6 were the most frequently implicated genes, respectively in syndromic and isolated PA."
Assigns B3GLCT to syndromic and PAX6 to isolated Peters anomaly, the cleanest statement of the split.
Peters-plus-like syndrome
Overlapping Features Individuals who display a PTRPLS-like clinical pattern but lack diagnostic biallelic B3GLCT variants. Some carry B3GLCT missense changes, but functional testing shows these retain enzymatic activity, so the underlying cause is not loss of the Glc-beta1,3-Fuc disaccharide. Copy-number variants involving other loci can produce the pattern: a de novo 1.6 Mb deletion spanning PEX2 and ZFHX4 was reported in a patient with a Peters-plus-like phenotype.
Distinguishing Features
  • Incomplete or atypical clinical constellation relative to classic PTRPLS
  • No biallelic loss-of-function B3GLCT genotype
  • B3GLCT alleles, when present, retain catalytic activity in vitro
  • May be explained by copy-number variants at other loci, such as a PEX2-ZFHX4 deletion
Show evidence (3 references)
PMID:34058199 SUPPORT In Vitro
"In contrast, B3GLCT with PTRPLS-like mutations retained enzymatic activity, although some showed a minor destabilizing effect."
Functional data distinguishing true PTRPLS alleles from those seen in partial phenotypes.
PMID:40650233 SUPPORT Human Clinical
"In the first patient, a heterozygous ~1.6 Mb deletion was detected, spanning the genes PEX2 and ZFHX4"
Documents a non-B3GLCT copy-number cause of a Peters-plus-like presentation.
PMID:40650233 SUPPORT Human Clinical
"with the first patient displaying both ocular and systemic anomalies as in a Peters plus-like syndrome phenotype, while the second patient had isolated ocular manifestations as in a PA type 1 phenotype"
Illustrates the clinical separation of Peters-plus-like from isolated Peters anomaly within the same cohort.
🐁

Animal Models

2
B3glct knockout mouse
Two independent B3glct knockout alleles reproduce craniofacial and skeletal abnormalities comparable to human PTRPLS, together with highly penetrant hydrocephalus, white coat spotting, and soft-tissue syndactyly. Genetic and biochemical dissection attributes the hydrocephalus and white spotting to loss of ADAMTS20, the eye abnormalities to partial reduction of ADAMTS9, and the cleft palate to both. This is the most informative whole-animal model of the syndrome.
Species
Mouse
Genotype
B3glct knockout
Genes
B3GLCT hgnc:20207 HUGO Gene Nomenclature Committee (hgnc) Relation: this experimental model concerns this gene This experimental model concerns B3GLCT (hgnc:20207). hgnc:20207 is a gene from the HUGO Gene Nomenclature Committee.
Show evidence (2 references)
PMID:31600785 SUPPORT Model Organism
"we developed and characterized two mouse B3glct knockout alleles"
Establishes the mouse knockout as the principal in vivo model.
PMID:31600785 SUPPORT Model Organism
"In addition, we observed highly penetrant hydrocephalus, white spotting and soft tissue syndactyly."
Notes mouse-specific findings that extend beyond the recognized human phenotype and limit one-to-one phenotype transfer.
b3glcta/b3glctb double-knockout zebrafish
TALEN-generated single and double knockouts of the two zebrafish B3GLCT orthologs abolish in vitro b3glct activity, yet double-homozygous fish develop normally. Transcriptome analysis identified 483 differentially regulated transcripts that may reflect compensation. The model therefore does not recapitulate the human disease and is of limited value for phenotype studies despite conserved enzyme function.
Species
Zebrafish
Genotype
b3glcta/b3glctb double knockout
Genes
B3GLCT hgnc:20207 HUGO Gene Nomenclature Committee (hgnc) Relation: this experimental model concerns this gene This experimental model concerns B3GLCT (hgnc:20207). hgnc:20207 is a gene from the HUGO Gene Nomenclature Committee.
Show evidence (2 references)
PMID:28926587 REFUTE Model Organism
"Surprisingly, b3glct-/- homozygous fish developed normally."
The zebrafish null does not reproduce the human phenotype, refuting its utility as a disease model.
PMID:28926587 SUPPORT In Vitro
"Extracts from double homozygous b3glct-/- embryos demonstrated complete loss of in vitro b3glct activity."
Confirms the knockout is a true enzymatic null, so the absent phenotype is not a technical failure of gene targeting.
{ }

Source YAML

click to show 
name: Peters plus syndrome
creation_date: "2026-08-01T00:00:00Z"
description: >-
  Peters plus syndrome (PTRPLS, Krause-Kivlin syndrome) is a rare autosomal
  recessive congenital disorder of glycosylation caused by biallelic
  loss-of-function variants in B3GLCT (formerly B3GALTL), which encodes
  beta-1,3-glucosyltransferase. B3GLCT performs the second step of a
  noncanonical endoplasmic-reticulum quality-control pathway: protein
  O-fucosyltransferase 2 (POFUT2) recognizes correctly folded thrombospondin
  type-1 repeats (TSRs) and attaches O-fucose, and B3GLCT then elongates it to
  the glucose-beta-1,3-fucose disaccharide. Unlike classical ER quality control,
  which tags unfolded protein, this pathway marks and stabilizes the folded
  state. Losing the terminal glucose destabilizes TSRs and impairs ER exit and
  secretion of a subset of the 49 predicted TSR-containing targets, most of
  which belong to the ADAMTS/ADAMTSL and thrombospondin families. Clinically the
  syndrome combines Peters anomaly and other anterior-segment eye anomalies with
  disproportionate rhizomelic short stature, brachydactyly with broad hands and
  feet, distinctive facies (exaggerated cupid's-bow upper lip, prominent
  forehead, hypertelorism), variable developmental delay or intellectual
  disability, and occasional cleft lip/palate and congenital heart defects. It
  is distinct from isolated Peters anomaly and from "Peters-plus-like"
  phenotypes, in neither of which biallelic loss-of-function B3GLCT variants are
  found.
category: Mendelian
parents:
- syndromic disease
- autosomal recessive disease
- congenital disorder of glycosylation
synonyms:
- PTRPLS
- Krause-Kivlin syndrome
- Krause-van Schooneveld-Kivlin syndrome
- Peters anomaly with short limb dwarfism
- B3GALTL deficiency
- B3GLCT-related Peters plus syndrome
disease_term:
  preferred_term: Peters plus syndrome
  term:
    id: MONDO:0009856
    label: Peters plus syndrome
references:
- reference: PMID:20301637
  title: "Peters Plus Syndrome."
  tags:
  - GeneReviews
classifications:
  icimd_category:
  - classification_value: o_linked_protein_glycosylation
    notes: >-
      Peters plus syndrome is an ICIMD congenital disorder of glycosylation
      affecting O-linked (specifically O-fucose) protein glycosylation: B3GLCT
      elongates O-fucose on thrombospondin type-1 repeats to the
      glucose-beta-1,3-fucose disaccharide.
  harrisons_chapter:
  - classification_value: GENETICS_ENVIRONMENT_DISEASE
    notes: >-
      A monogenic autosomal recessive multiple-congenital-anomaly syndrome; the
      dominant clinical framing is medical genetics rather than a single organ
      system.
prevalence:
- population: Worldwide
  measure_type: UNKNOWN
  prevalence_class: ULTRA_RARE
  notes: >-
    No robust PTRPLS-specific prevalence or incidence estimate exists; the
    literature consistently describes it only qualitatively as a very rare
    subtype of anterior segment dysgenesis. The population figure of 2.2-3.1 per
    100,000 births that appears in recent literature applies to the broader
    Peters anomaly spectrum and must NOT be relabelled as a Peters plus syndrome
    rate. Orphanet (ORPHA:709) would be the natural structured source but no
    ORPHA cache record could be generated in this repository.
  evidence:
  - reference: PMID:31795264
    reference_title: "Contribution of a Novel B3GLCT Variant to Peters Plus Syndrome Discovered by a Combination of Next-Generation Sequencing and Automated Text Mining."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      PPS, a very rare subtype of ASD, is a glycosylation disorder
    explanation: >-
      Supports only the qualitative rarity band; no quantitative rate is
      asserted anywhere in the reviewed literature.
inheritance:
- name: Autosomal recessive inheritance
  description: >-
    PTRPLS is autosomal recessive. Affected individuals carry biallelic
    pathogenic B3GLCT variants, or one pathogenic B3GLCT variant in trans with a
    contiguous 13q12.3 deletion that includes B3GLCT. The observed sibling
    recurrence risk at birth is lower than the theoretical 25% because of
    increased miscarriage and second- and third-trimester loss of affected
    fetuses.
  inheritance_term:
    preferred_term: Autosomal recessive inheritance
    term:
      id: HP:0000007
      label: Autosomal recessive inheritance
  evidence:
  - reference: PMID:20301637
    reference_title: "Peters Plus Syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      PTRPLS is inherited in an autosomal recessive manner. If both parents are
      known to be heterozygous for a pathogenic variant involving B3GLCT, each
      sib of an affected individual has at conception a 25% chance of being
      affected
    explanation: >-
      GeneReviews establishes the autosomal recessive mode of inheritance and
      the recurrence risk.
  - reference: PMID:16909395
    reference_title: "Peters Plus syndrome is caused by mutations in B3GALTL, a putative glycosyltransferase."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      we identified biallelic truncating mutations in the beta
      1,3-galactosyltransferase-like gene (B3GALTL) in all 20 tested patients,
      showing that Peters Plus is a monogenic, primarily single-mutation
      syndrome
    explanation: >-
      The gene-discovery study documents biallelic (recessive) truncating
      variants in every tested proband.
pathophysiology:
- name: B3GLCT Loss of Function
  biological_scale: MOLECULAR
  description: >-
    Biallelic loss-of-function variants in B3GLCT abolish or severely reduce
    beta-1,3-glucosyltransferase activity. The recurrent intronic splice-donor
    allele c.660+1G>A accounts for the majority of reported pathogenic alleles;
    frameshift, nonsense, other splice, and rare missense alleles complete the
    spectrum. In vitro assays show that PTRPLS-associated substitutions cause
    loss of catalytic activity and/or destabilize the protein, whereas
    substitutions found only in milder "Peters-plus-like" patients retain
    activity - evidence that it is specifically the loss of glucose transfer,
    not any B3GLCT sequence change, that produces the syndrome.
  genes:
  - preferred_term: B3GLCT
    term:
      id: hgnc:20207
      label: B3GLCT
  molecular_functions:
  - preferred_term: beta-1,3-glucosyltransferase activity
    term:
      id: GO:0046527
      label: glucosyltransferase activity
    modifier: DECREASED
  evidence:
  - reference: PMID:16909395
    reference_title: "Peters Plus syndrome is caused by mutations in B3GALTL, a putative glycosyltransferase."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      After detection of a microdeletion by array-based comparative genomic
      hybridization, we identified biallelic truncating mutations in the beta
      1,3-galactosyltransferase-like gene (B3GALTL) in all 20 tested patients
    explanation: >-
      Establishes biallelic truncating B3GLCT (B3GALTL) variants as the cause of
      Peters plus syndrome.
  - reference: PMID:34058199
    reference_title: "Peters plus syndrome mutations affect the function and stability of human beta1,3-glucosyltransferase."
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: >-
      Our results demonstrated that PTRPLS mutations caused loss of B3GLCT
      enzymatic activity and/or significantly reduced protein stability.
    explanation: >-
      Functional assays confirm that PTRPLS alleles are loss-of-function at the
      level of enzyme activity or protein stability.
  - reference: PMID:34058199
    reference_title: "Peters plus syndrome mutations affect the function and stability of human beta1,3-glucosyltransferase."
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: >-
      Overall, our data supports the hypothesis that loss of glucose from B3GLCT
      substrate proteins is responsible for the defects observed in PTRPLS
      patients, but not for those observed in PTRPLS-like patients.
    explanation: >-
      Ties the disease specifically to loss of the glucose transfer reaction and
      separates it from PTRPLS-like phenotypes.
  downstream:
  - target: Absent Glucose-beta-1,3-Fucose Disaccharide on Thrombospondin Type-1 Repeats
    causal_link_type: DIRECT
    description: >-
      Without B3GLCT activity the O-fucose added to TSRs by POFUT2 cannot be
      elongated to the Glc-beta1,3-Fuc disaccharide.
    evidence:
    - reference: PMID:18199743
      reference_title: "Peters Plus syndrome is a new congenital disorder of glycosylation and involves defective Omicron-glycosylation of thrombospondin type 1 repeats."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        In properdin from patients, we could not detect the
        Glc-beta1,3-Fuc-Omicron-disaccharide, and we only found
        Fuc-Omicron-at all four Omicron-fucosylation sites.
      explanation: >-
        Direct demonstration in patient material that the disaccharide is absent
        and only the O-fucose monosaccharide remains.
- name: Absent Glucose-beta-1,3-Fucose Disaccharide on Thrombospondin Type-1 Repeats
  conforms_to: "tsr_o_glycosylation_quality_control#Absent Glucose-beta-1,3-Fucose Disaccharide on Thrombospondin Type-1 Repeats"
  biological_scale: MOLECULAR
  description: >-
    POFUT2 and B3GLCT act sequentially to add an O-linked
    glucose-beta-1,3-fucose disaccharide to properly folded thrombospondin
    type-1 repeats. In PTRPLS the pathway stalls after the first step, so TSRs
    on target glycoproteins carry only O-fucose. This was shown directly in
    patient-derived properdin, the reporter protein used to establish PTRPLS as
    a congenital disorder of glycosylation; loss of the disaccharide on
    properdin remains the only human biochemical readout of functional null
    status.
  biological_processes:
  - preferred_term: protein O-linked glycosylation via glucose
    term:
      id: GO:0180059
      label: protein O-linked glycosylation via glucose
    modifier: DECREASED
  - preferred_term: protein O-linked glycosylation
    term:
      id: GO:0006493
      label: protein O-linked glycosylation
    modifier: DECREASED
  evidence:
  - reference: PMID:18199743
    reference_title: "Peters Plus syndrome is a new congenital disorder of glycosylation and involves defective Omicron-glycosylation of thrombospondin type 1 repeats."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      In contrast, properdin from heterozygous relatives and a healthy volunteer
      carried the Glc-beta1,3-Fuc-Omicron-disaccharide. These data firmly
      establish Peters Plus syndrome as a new congenital disorder of
      glycosylation.
    explanation: >-
      Patient-versus-control comparison establishes the specific glycosylation
      lesion and classifies PTRPLS as a CDG.
  - reference: PMID:25544610
    reference_title: "Peters plus syndrome mutations disrupt a noncanonical ER quality-control mechanism."
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: >-
      O-fucose is added to cysteine-rich domains called thrombospondin type 1
      repeats (TSRs) by protein O-fucosyltransferase 2 (POFUT2) and is elongated
      with glucose by β3-glucosyltransferase (B3GLCT).
    explanation: >-
      States the two-enzyme sequential reaction that B3GLCT loss interrupts.
  downstream:
  - target: Impaired ER Quality Control and Secretion of TSR-Containing Proteins
    causal_link_type: DIRECT
    description: >-
      Fucose and glucose stabilize the folded TSR additively; without the
      glucose, folded TSRs are less stable and ER exit is less efficient.
    evidence:
    - reference: PMID:25544610
      reference_title: "Peters plus syndrome mutations disrupt a noncanonical ER quality-control mechanism."
      supports: SUPPORT
      evidence_source: IN_VITRO
      snippet: >-
        In vitro unfolding assays demonstrate that fucose and glucose stabilize
        folded TSRs in an additive manner.
      explanation: >-
        Direct biophysical evidence that the terminal glucose contributes to TSR
        stability, which is the immediate consequence of B3GLCT loss.
- name: Impaired ER Quality Control and Secretion of TSR-Containing Proteins
  conforms_to: "tsr_o_glycosylation_quality_control#Impaired ER Quality Control and Secretion of TSR-Containing Proteins"
  biological_scale: CELLULAR
  description: >-
    POFUT2 and B3GLCT together constitute a noncanonical endoplasmic-reticulum
    quality-control mechanism. Where classical ER quality control identifies and
    tags unfolded protein, this pathway recognizes the FOLDED TSR
    cotranslationally and stabilizes it by glycosylation, marking it for ER
    exit. Loss of the terminal glucose therefore reduces the secretion
    efficiency of a subset of the 49 predicted TSR-modified proteins - a subset,
    not all of them, which is why PTRPLS is survivable while Pofut2-null mice
    are embryonic lethal. Nearly half of the targets are members of the ADAMTS
    superfamily, which act in the extracellular matrix.
  biological_processes:
  - preferred_term: protein folding in endoplasmic reticulum
    term:
      id: GO:0034975
      label: protein folding in endoplasmic reticulum
    modifier: ABNORMAL
  - preferred_term: protein secretion
    term:
      id: GO:0009306
      label: protein secretion
    modifier: DECREASED
  cellular_components:
  - preferred_term: endoplasmic reticulum
    term:
      id: GO:0005783
      label: endoplasmic reticulum
  evidence:
  - reference: PMID:25544610
    reference_title: "Peters plus syndrome mutations disrupt a noncanonical ER quality-control mechanism."
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: >-
      While known ER quality-control machinery rely on identifying and tagging
      unfolded proteins, we find that POFUT2 and B3GLCT mediate a noncanonical
      ER quality-control mechanism that recognizes folded TSRs and stabilizes
      them by glycosylation.
    explanation: >-
      Defines the noncanonical, folded-state-recognizing quality-control
      mechanism that B3GLCT loss disrupts.
  - reference: PMID:25544610
    reference_title: "Peters plus syndrome mutations disrupt a noncanonical ER quality-control mechanism."
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: >-
      Here we show that while POFUT2 is required for secretion of all targets
      tested, B3GLCT only affects the secretion of a subset, consistent with the
      observation that B3GLCT mutant phenotypes in PPS patients are less severe
      than embryonic lethal phenotypes of Pofut2-null mice.
    explanation: >-
      Explains the selective, sub-lethal character of the human phenotype: only
      some TSR targets depend on the B3GLCT step.
  - reference: PMID:31600785
    reference_title: "ADAMTS9 and ADAMTS20 are differentially affected by loss of B3GLCT in mouse model of Peters plus syndrome."
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: >-
      Forty-nine proteins are predicted to be modified by POFUT2, and nearly
      half are members of the ADAMTS superfamily.
    explanation: >-
      Quantifies the target repertoire and identifies ADAMTS proteins as the
      dominant substrate class.
  downstream:
  - target: Reduced ADAMTS9 and ADAMTS20 Function in the Extracellular Matrix
    causal_link_type: DIRECT
    description: >-
      ADAMTS9 and ADAMTS20 are among the TSR targets most sensitive to loss of
      the disaccharide, and mouse genetics attributes distinct PTRPLS-like
      defects to each.
    evidence:
    - reference: PMID:31600785
      reference_title: "ADAMTS9 and ADAMTS20 are differentially affected by loss of B3GLCT in mouse model of Peters plus syndrome."
      supports: SUPPORT
      evidence_source: MODEL_ORGANISM
      snippet: >-
        Combined, these results provide compelling evidence that ADAMTS9 and
        ADAMTS20 were differentially sensitive to B3GLCT inactivation and
        suggest that the developmental defects in PTRPLS result from disruption
        of a subset of highly sensitive POFUT2/B3GLCT targets such as ADAMTS20.
      explanation: >-
        Establishes ADAMTS9/ADAMTS20 as the key effectors downstream of B3GLCT
        loss in the mouse model.
- name: Reduced ADAMTS9 and ADAMTS20 Function in the Extracellular Matrix
  biological_scale: TISSUE
  description: >-
    Under-secretion of TSR-bearing ADAMTS metalloproteinases degrades
    extracellular-matrix remodelling during organogenesis. In B3glct knockout
    mice the pattern is target-specific: hydrocephalus and white spotting track
    with loss of ADAMTS20, eye abnormalities with partial reduction of ADAMTS9,
    and cleft palate with the combination of both.
  biological_processes:
  - preferred_term: extracellular matrix organization
    term:
      id: GO:0030198
      label: extracellular matrix organization
    modifier: ABNORMAL
  evidence:
  - reference: PMID:31600785
    reference_title: "ADAMTS9 and ADAMTS20 are differentially affected by loss of B3GLCT in mouse model of Peters plus syndrome."
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: >-
      We provide strong genetic and biochemical evidence that hydrocephalus and
      white spotting in B3glct mutants resulted from loss of ADAMTS20, eye
      abnormalities from partial reduction of ADAMTS9 and cleft palate from loss
      of ADAMTS20 and partially reduced ADAMTS9 function.
    explanation: >-
      Assigns individual PTRPLS-like malformations to specific ADAMTS effectors.
  downstream:
  - target: Anterior Segment Dysgenesis
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    description: >-
      Reduced ADAMTS9 activity is the mouse-genetic correlate of the ocular
      defects; the intervening steps between reduced ADAMTS9 secretion and
      failure of anterior-segment separation are not established.
    evidence:
    - reference: PMID:31600785
      reference_title: "ADAMTS9 and ADAMTS20 are differentially affected by loss of B3GLCT in mouse model of Peters plus syndrome."
      supports: SUPPORT
      evidence_source: MODEL_ORGANISM
      snippet: >-
        eye abnormalities from partial reduction of ADAMTS9
      explanation: >-
        Attributes the ocular arm of the phenotype to partial ADAMTS9 loss.
  - target: Impaired Craniofacial and Endochondral Skeletal Growth
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    description: >-
      B3glct knockout mice reproduce the craniofacial and skeletal arm of the
      human phenotype, but the specific TSR targets mediating growth-plate and
      craniofacial effects have not been resolved.
    evidence:
    - reference: PMID:31600785
      reference_title: "ADAMTS9 and ADAMTS20 are differentially affected by loss of B3GLCT in mouse model of Peters plus syndrome."
      supports: SUPPORT
      evidence_source: MODEL_ORGANISM
      snippet: >-
        The mouse B3glct mutants developed craniofacial and skeletal
        abnormalities comparable to PTRPLS.
      explanation: >-
        Establishes that loss of B3GLCT is sufficient to produce the
        craniofacial and skeletal phenotype in vivo.
  - target: Failure of Palatal Shelf Fusion
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    description: >-
      Cleft palate in the mouse model requires combined ADAMTS20 loss and
      partial ADAMTS9 reduction.
    evidence:
    - reference: PMID:31600785
      reference_title: "ADAMTS9 and ADAMTS20 are differentially affected by loss of B3GLCT in mouse model of Peters plus syndrome."
      supports: SUPPORT
      evidence_source: MODEL_ORGANISM
      snippet: >-
        cleft palate from loss of ADAMTS20 and partially reduced ADAMTS9
        function
      explanation: >-
        Assigns the orofacial-clefting arm to a two-target ADAMTS deficit.
- name: Anterior Segment Dysgenesis
  conforms_to: "anterior_segment_dysgenesis#Failed Differentiation and Separation of Anterior Segment Tissues"
  biological_scale: TISSUE
  description: >-
    Defective remodelling of the developing anterior eye segment produces Peters
    anomaly: failure to separate the lens vesicle and/or iris from the surface
    ectoderm-derived cornea, leaving posterior corneal (Descemet membrane and
    endothelium) defects with iridocorneal and sometimes keratolenticular
    adhesions. Deep ocular phenotyping in PTRPLS most often shows an avascular
    paracentral ring opacity caused by iridocorneal adhesion, with relative
    central clearing over an area of posterior stromal thinning; a large
    vascularized central opacity is the less common alternative pattern.
    Periocular neural-crest-derived mesenchyme populates these structures, and
    abnormal neural crest development was the leading pre-molecular hypothesis
    for the syndrome.
  cell_types:
  - preferred_term: periocular neural crest cell
    term:
      id: CL:0011012
      label: neural crest cell
  - preferred_term: corneal endothelial cell
    term:
      id: CL:0000132
      label: corneal endothelial cell
  - preferred_term: corneal stromal keratocyte
    term:
      id: CL:0002363
      label: keratocyte
  biological_processes:
  - preferred_term: cornea development in camera-type eye
    term:
      id: GO:0061303
      label: cornea development in camera-type eye
    modifier: ABNORMAL
  - preferred_term: neural crest cell development
    term:
      id: GO:0014032
      label: neural crest cell development
    modifier: ABNORMAL
  locations:
  - preferred_term: anterior segment of eyeball
    term:
      id: UBERON:0001801
      label: anterior segment of eyeball
  evidence:
  - reference: PMID:34629439
    reference_title: "Ocular Phenotype of Peters-Plus Syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      The paracentral opacity is due to iridocorneal adhesion and the relative
      central clearing associated with posterior stromal thinning.
    explanation: >-
      Deep phenotyping identifies the anatomical lesion underlying the corneal
      opacity in PTRPLS.
  - reference: PMID:35170016
    reference_title: "First evidence of SOX2 mutations in Peters' anomaly: Lessons from molecular screening of 95 patients."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Peters' anomaly (PA) is a rare anterior segment dysgenesis characterized
      by central corneal opacity and irido-lenticulo-corneal adhesions.
    explanation: >-
      Defines the anatomical lesion of Peters anomaly that this node models.
  - reference: PMID:12119218
    reference_title: "The Peters' plus syndrome: a review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      The etiology is unknown, but may involve abnormal neural crest
      development.
    explanation: >-
      Records the pre-molecular neural-crest hypothesis for the anterior-segment
      lesion; it remains a plausible cellular substrate but has not been
      directly demonstrated for B3GLCT loss.
- name: Impaired Craniofacial and Endochondral Skeletal Growth
  biological_scale: TISSUE
  description: >-
    Disrupted extracellular-matrix remodelling in the growth plate and
    craniofacial skeleton produces disproportionate, rhizomelic short stature
    with brachydactyly and broad hands and feet, and the characteristic facial
    gestalt. B3glct knockout mice reproduce craniofacial and skeletal
    abnormalities comparable to the human syndrome.
  cell_types:
  - preferred_term: growth plate chondrocyte
    term:
      id: CL:0000138
      label: chondrocyte
  biological_processes:
  - preferred_term: endochondral bone growth
    term:
      id: GO:0003416
      label: endochondral bone growth
    modifier: DECREASED
  - preferred_term: skeletal system development
    term:
      id: GO:0001501
      label: skeletal system development
    modifier: ABNORMAL
  - preferred_term: limb development
    term:
      id: GO:0060173
      label: limb development
    modifier: ABNORMAL
  locations:
  - preferred_term: growth plate
    term:
      id: UBERON:0002516
      label: epiphyseal plate
  - preferred_term: skeletal system
    term:
      id: UBERON:0001434
      label: skeletal system
  evidence:
  - reference: PMID:31600785
    reference_title: "ADAMTS9 and ADAMTS20 are differentially affected by loss of B3GLCT in mouse model of Peters plus syndrome."
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: >-
      The mouse B3glct mutants developed craniofacial and skeletal
      abnormalities comparable to PTRPLS.
    explanation: >-
      Animal-model support for the skeletal and craniofacial arm of the
      pathophysiology.
  - reference: PMID:34058199
    reference_title: "Peters plus syndrome mutations affect the function and stability of human beta1,3-glucosyltransferase."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      patients have multiple structural anomalies, including Peters anomaly of
      the eye (anterior segment dysgenesis), disproportionate short stature,
      brachydactyly, dysmorphic facial features, developmental delay
    explanation: >-
      Confirms the skeletal-growth and craniofacial manifestations in patients.
      Classified OTHER because the quoted sentence is this in vitro study's
      restatement of the established human clinical description, not new
      patient data that the paper itself reports.
- name: Failure of Palatal Shelf Fusion
  biological_scale: TISSUE
  description: >-
    A subset of individuals develop cleft lip and/or palate. In the B3glct
    mouse, cleft palate arises only when ADAMTS20 is lost and ADAMTS9 is
    partially reduced, indicating that palatal shelf fusion is a
    combined-dosage-sensitive readout of the pathway.
  biological_processes:
  - preferred_term: roof of mouth development
    term:
      id: GO:0060021
      label: roof of mouth development
    modifier: ABNORMAL
  locations:
  - preferred_term: secondary palate
    term:
      id: UBERON:0001716
      label: secondary palate
  evidence:
  - reference: PMID:31600785
    reference_title: "ADAMTS9 and ADAMTS20 are differentially affected by loss of B3GLCT in mouse model of Peters plus syndrome."
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: >-
      cleft palate from loss of ADAMTS20 and partially reduced ADAMTS9 function
    explanation: >-
      Mechanistic attribution of clefting to combined ADAMTS20/ADAMTS9 deficit.
  - reference: PMID:18199743
    reference_title: "Peters Plus syndrome is a new congenital disorder of glycosylation and involves defective Omicron-glycosylation of thrombospondin type 1 repeats."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Peters Plus syndrome is an autosomal recessive disorder characterized by
      anterior eye chamber defects, disproportionate short stature,
      developmental delay, and cleft lip and/or palate.
    explanation: >-
      Confirms orofacial clefting as part of the human clinical definition.
phenotypes:
- category: Ophthalmologic
  name: Peters Anomaly
  description: >-
    The cardinal ocular malformation: central or paracentral posterior corneal
    defect with iridocorneal and/or keratolenticular adhesion, producing corneal
    opacity of varying degree. In PTRPLS the most common pattern is an avascular
    paracentral ring opacity with relative central clearing.
  phenotype_term:
    preferred_term: Peters anomaly
    term:
      id: HP:0000659
      label: Peters anomaly
  diagnostic: true
  evidence:
  - reference: PMID:20301637
    reference_title: "Peters Plus Syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Peters plus syndrome (PTRPLS) is characterized by congenital eye
      anomalies, particularly Peters anomaly, which results in varying degrees
      of corneal opacity and lens anomalies
    explanation: >-
      GeneReviews identifies Peters anomaly as the characteristic congenital eye
      anomaly of the syndrome.
  - reference: PMID:34629439
    reference_title: "Ocular Phenotype of Peters-Plus Syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      The most common ocular phenotype seen in Peters-plus syndrome is an
      avascular paracentral ring opacity with relative central clearing. A
      different phenotype with a large vascularized corneal opacity may also be
      observed.
    explanation: >-
      Case series characterizing the two ocular sub-phenotypes of PTRPLS.
- category: Ophthalmologic
  name: Corneal Opacity
  description: >-
    Corneal clouding of varying degree, the visible consequence of the posterior
    corneal defect and iridocorneal adhesion.
  phenotype_term:
    preferred_term: Corneal opacity
    term:
      id: HP:0007957
      label: Corneal opacity
  evidence:
  - reference: PMID:20301637
    reference_title: "Peters Plus Syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      which results in varying degrees of corneal opacity and lens anomalies, as
      well as an increased risk of glaucoma
    explanation: >-
      GeneReviews documents corneal opacity as a direct consequence of the
      Peters anomaly.
- category: Ophthalmologic
  name: Lens Anomalies
  description: >-
    Lens abnormalities including keratolenticular adhesion and cataract, arising
    from failure of lens vesicle separation from the developing cornea.
  phenotype_term:
    preferred_term: Abnormal lens morphology
    term:
      id: HP:0000517
      label: Abnormal lens morphology
  evidence:
  - reference: PMID:20301637
    reference_title: "Peters Plus Syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      which results in varying degrees of corneal opacity and lens anomalies
    explanation: >-
      GeneReviews lists lens anomalies among the core ocular findings.
- category: Ophthalmologic
  name: Glaucoma
  description: >-
    Anterior-segment dysgenesis compromises aqueous outflow, and glaucoma is a
    recognized and vision-threatening complication requiring lifelong
    surveillance beginning in early infancy. Frequency estimates of 30-70%
    circulating in the literature apply to the broader Peters anomaly spectrum,
    not to molecularly confirmed PTRPLS, so no frequency band is asserted here.
  phenotype_term:
    preferred_term: Glaucoma
    term:
      id: HP:0000501
      label: Glaucoma
  evidence:
  - reference: PMID:20301637
    reference_title: "Peters Plus Syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      as well as an increased risk of glaucoma
    explanation: >-
      GeneReviews records increased glaucoma risk as part of the ocular
      phenotype.
- category: Ophthalmologic
  name: Microphthalmia
  description: >-
    Reduced globe size, reported in a subset of affected individuals and
    detectable prenatally.
  phenotype_term:
    preferred_term: Microphthalmia
    term:
      id: HP:0000568
      label: Microphthalmia
  evidence:
  - reference: PMID:20301637
    reference_title: "Peters Plus Syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Other eye findings can include posterior segment abnormalities (including
      retinal and/or optic nerve coloboma) and microphthalmia.
    explanation: >-
      GeneReviews lists microphthalmia among the additional ocular findings.
  - reference: PMID:15912477
    reference_title: "Prenatal sonographic findings in Peters-plus syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Ultrasound examination revealed microphthalmia and hyperechogenicity of
      the anterior part of the eye with a central defect
    explanation: >-
      Documents microphthalmia detected on prenatal ultrasound in a
      subsequently autopsy-confirmed case.
- category: Ophthalmologic
  name: Coloboma
  description: >-
    Retinal and/or optic nerve coloboma, part of the posterior-segment
    involvement that can accompany the anterior-segment dysgenesis.
  phenotype_term:
    preferred_term: Coloboma
    term:
      id: HP:0000589
      label: Coloboma
  evidence:
  - reference: PMID:20301637
    reference_title: "Peters Plus Syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Other eye findings can include posterior segment abnormalities (including
      retinal and/or optic nerve coloboma)
    explanation: >-
      GeneReviews documents retinal and optic nerve coloboma in PTRPLS.
- category: Ophthalmologic
  name: Visual Impairment
  description: >-
    Reduced vision, the functional consequence of the corneal opacity and its
    complications; severity ranges from useful residual sight to blindness, and
    deprivation amblyopia compounds the structural deficit if the visual axis is
    not cleared early.
  phenotype_term:
    preferred_term: Visual impairment
    term:
      id: HP:0000505
      label: Visual impairment
  evidence:
  - reference: PMID:31600785
    reference_title: "ADAMTS9 and ADAMTS20 are differentially affected by loss of B3GLCT in mouse model of Peters plus syndrome."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      it results in corneal opacity, with severe visual impairment and other eye
      complications
    explanation: >-
      Identifies visual impairment as the functional outcome of the Peters
      anomaly. Classified OTHER because the sentence is this mouse study's
      restatement of the established human clinical description rather than its
      own data.
- category: Neurologic
  name: Hydrocephalus
  description: >-
    Reported in postmortem analysis of PTRPLS fetuses. Notably, hydrocephalus is
    also highly penetrant in the B3glct knockout mouse, where it is attributed to
    loss of ADAMTS20 - so this is a point of human-mouse concordance at the
    severe/prenatal end of the spectrum rather than a mouse-only finding.
  phenotype_term:
    preferred_term: Hydrocephalus
    term:
      id: HP:0000238
      label: Hydrocephalus
  evidence:
  - reference: PMID:31600785
    reference_title: "ADAMTS9 and ADAMTS20 are differentially affected by loss of B3GLCT in mouse model of Peters plus syndrome."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      postmortem analysis of PTRPLS fetuses identified additional abnormalities
      including growth retardation, hydrocephalus, agenesis of the corpus
      callosum, Dandy-Walker cyst and gut anomalies
    explanation: >-
      Documents hydrocephalus in human PTRPLS fetuses at postmortem. Classified
      OTHER because this mouse paper is citing a separate human postmortem
      series rather than reporting the finding itself.
- category: Neurologic
  name: Agenesis of the Corpus Callosum
  description: >-
    Midline forebrain commissural defect identified in postmortem analysis of
    PTRPLS fetuses; part of the severe end of the CNS spectrum that is
    under-represented in liveborn clinical series.
  phenotype_term:
    preferred_term: Agenesis of corpus callosum
    term:
      id: HP:0001274
      label: Agenesis of corpus callosum
  evidence:
  - reference: PMID:31600785
    reference_title: "ADAMTS9 and ADAMTS20 are differentially affected by loss of B3GLCT in mouse model of Peters plus syndrome."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      postmortem analysis of PTRPLS fetuses identified additional abnormalities
      including growth retardation, hydrocephalus, agenesis of the corpus
      callosum, Dandy-Walker cyst and gut anomalies
    explanation: >-
      Documents agenesis of the corpus callosum in human PTRPLS fetuses.
      Classified OTHER because this mouse paper is citing a separate human
      postmortem series rather than reporting the finding itself.
- category: Neurologic
  name: Dandy-Walker Malformation
  description: >-
    Posterior fossa cystic malformation reported in postmortem analysis of
    PTRPLS fetuses.
  phenotype_term:
    preferred_term: Dandy-Walker malformation
    term:
      id: HP:0001305
      label: Dandy-Walker malformation
  evidence:
  - reference: PMID:31600785
    reference_title: "ADAMTS9 and ADAMTS20 are differentially affected by loss of B3GLCT in mouse model of Peters plus syndrome."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      postmortem analysis of PTRPLS fetuses identified additional abnormalities
      including growth retardation, hydrocephalus, agenesis of the corpus
      callosum, Dandy-Walker cyst and gut anomalies
    explanation: >-
      Documents a Dandy-Walker cyst in human PTRPLS fetuses. Classified OTHER
      because this mouse paper is citing a separate human postmortem series
      rather than reporting the finding itself.
- category: Skeletal
  name: Disproportionate Short Stature
  description: >-
    Growth restriction with disproportionate, rhizomelic limb shortening. Short
    stature is one of the three defining clinical axes of the syndrome.
  phenotype_term:
    preferred_term: Disproportionate short stature
    term:
      id: HP:0003498
      label: Disproportionate short stature
  diagnostic: true
  evidence:
  - reference: PMID:20301637
    reference_title: "Peters Plus Syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Additional non-ophthalmologic findings include short stature with
      rhizomelic shortening of the limbs with broad hands and feet
    explanation: >-
      GeneReviews establishes disproportionate short stature with rhizomelic
      limb shortening.
  - reference: PMID:16909395
    reference_title: "Peters Plus syndrome is caused by mutations in B3GALTL, a putative glycosyltransferase."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Peters Plus syndrome is an autosomal recessive disorder characterized by
      anterior eye-chamber abnormalities, disproportionate short stature, and
      developmental delay.
    explanation: >-
      Independent confirmation of disproportionate short stature as a defining
      feature.
- category: Skeletal
  name: Rhizomelic Limb Shortening
  description: >-
    Proximal (humerus/femur) predominant limb shortening, giving the
    disproportion its rhizomelic character.
  phenotype_term:
    preferred_term: Rhizomelia
    term:
      id: HP:0008905
      label: Rhizomelia
  evidence:
  - reference: PMID:20301637
    reference_title: "Peters Plus Syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      short stature with rhizomelic shortening of the limbs
    explanation: >-
      GeneReviews specifies the rhizomelic pattern of limb shortening.
- category: Skeletal
  name: Brachydactyly
  description: >-
    Short digits, part of the characteristic hand and foot morphology.
  phenotype_term:
    preferred_term: Brachydactyly
    term:
      id: HP:0001156
      label: Brachydactyly
  evidence:
  - reference: PMID:34058199
    reference_title: "Peters plus syndrome mutations affect the function and stability of human beta1,3-glucosyltransferase."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      Peters anomaly of the eye (anterior segment dysgenesis), disproportionate
      short stature, brachydactyly, dysmorphic facial features, developmental
      delay
    explanation: >-
      Lists brachydactyly among the core clinical features of PTRPLS.
      Classified OTHER because the quoted sentence is this in vitro study's
      restatement of the established human clinical description rather than new
      patient data.
  - reference: PMID:31600785
    reference_title: "ADAMTS9 and ADAMTS20 are differentially affected by loss of B3GLCT in mouse model of Peters plus syndrome."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      characterized by defects in eye development, prominent forehead,
      hypertelorism, short stature and brachydactyly
    explanation: >-
      Independent listing of brachydactyly in the clinical definition.
      Classified OTHER because the quoted sentence is this mouse study's
      restatement of the established human clinical description, not data from
      the mouse model or from patients it studied.
- category: Skeletal
  name: Broad Hands
  description: >-
    Broad palms accompanying the brachydactyly; together with broad feet this is
    a recognizable part of the syndrome gestalt.
  phenotype_term:
    preferred_term: Broad palm
    term:
      id: HP:0001169
      label: Broad palm
  evidence:
  - reference: PMID:20301637
    reference_title: "Peters Plus Syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      rhizomelic shortening of the limbs with broad hands and feet
    explanation: >-
      GeneReviews documents broad hands as part of the skeletal phenotype.
- category: Skeletal
  name: Broad Feet
  description: >-
    Broad feet, the pedal counterpart of the broad hands.
  phenotype_term:
    preferred_term: Broad foot
    term:
      id: HP:0001769
      label: Broad foot
  evidence:
  - reference: PMID:20301637
    reference_title: "Peters Plus Syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      rhizomelic shortening of the limbs with broad hands and feet
    explanation: >-
      GeneReviews documents broad feet as part of the skeletal phenotype.
- category: Neurologic
  name: Developmental Delay
  description: >-
    Variable global developmental delay, one of the three original defining
    axes. Severity ranges widely, and some affected individuals have normal
    cognition.
  phenotype_term:
    preferred_term: Global developmental delay
    term:
      id: HP:0001263
      label: Global developmental delay
  evidence:
  - reference: PMID:20301637
    reference_title: "Peters Plus Syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      variable developmental delay / intellectual disability, typical facial
      features
    explanation: >-
      GeneReviews documents variable developmental delay as a core
      non-ophthalmologic finding.
- category: Neurologic
  name: Intellectual Disability
  description: >-
    Intellectual disability of variable degree in a subset of affected
    individuals.
  phenotype_term:
    preferred_term: Intellectual disability
    term:
      id: HP:0001249
      label: Intellectual disability
  evidence:
  - reference: PMID:20301637
    reference_title: "Peters Plus Syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      variable developmental delay / intellectual disability
    explanation: >-
      GeneReviews records intellectual disability as a variable manifestation.
- category: Craniofacial
  name: Exaggerated Cupid's Bow Upper Lip
  description: >-
    A distinctive upper-lip vermilion contour ("cupid's bow"), one of the most
    recognizable facial features of the syndrome.
  phenotype_term:
    preferred_term: Exaggerated cupid's bow
    term:
      id: HP:0002263
      label: Exaggerated cupid's bow
  evidence:
  - reference: PMID:12119218
    reference_title: "The Peters' plus syndrome: a review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Major symptoms are extremely variable anterior chamber anomalies, cupid
      bow of the upper lip, cleft lip and palate, short stature, broad hands and
      feet, and variable mental delay.
    explanation: >-
      Clinical review lists the cupid's-bow upper lip among the major
      manifestations.
- category: Craniofacial
  name: Prominent Forehead
  description: >-
    Broad, prominent forehead contributing to the characteristic facies.
  phenotype_term:
    preferred_term: Prominent forehead
    term:
      id: HP:0011220
      label: Prominent forehead
  evidence:
  - reference: PMID:31600785
    reference_title: "ADAMTS9 and ADAMTS20 are differentially affected by loss of B3GLCT in mouse model of Peters plus syndrome."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      characterized by defects in eye development, prominent forehead,
      hypertelorism, short stature and brachydactyly
    explanation: >-
      Prominent forehead listed among the defining clinical features.
      Classified OTHER because the quoted sentence is this mouse study's
      restatement of the established human clinical description rather than its
      own patient or model data.
- category: Craniofacial
  name: Hypertelorism
  description: >-
    Increased interorbital distance, part of the facial gestalt.
  phenotype_term:
    preferred_term: Hypertelorism
    term:
      id: HP:0000316
      label: Hypertelorism
  evidence:
  - reference: PMID:31600785
    reference_title: "ADAMTS9 and ADAMTS20 are differentially affected by loss of B3GLCT in mouse model of Peters plus syndrome."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      characterized by defects in eye development, prominent forehead,
      hypertelorism, short stature and brachydactyly
    explanation: >-
      Hypertelorism listed among the defining clinical features. Classified
      OTHER because the quoted sentence is this mouse study's restatement of the
      established human clinical description rather than its own patient or
      model data.
- category: Craniofacial
  name: Cleft Lip
  description: >-
    Cleft of the upper lip, occurring in a subset of affected individuals and
    often together with cleft palate.
  phenotype_term:
    preferred_term: Cleft upper lip
    term:
      id: HP:0000204
      label: Cleft upper lip
  frequency: OCCASIONAL
  evidence:
  - reference: PMID:20301637
    reference_title: "Peters Plus Syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      and, occasionally, cleft lip/palate and congenital heart defects
    explanation: >-
      GeneReviews describes cleft lip/palate as an occasional finding, which
      maps to the OCCASIONAL frequency band (5-29%) in the project's
      prose-to-enum mapping table.
- category: Craniofacial
  name: Cleft Palate
  description: >-
    Cleft of the secondary palate, occurring in a subset of affected
    individuals; mechanistically attributed in the mouse model to combined
    ADAMTS20 loss and ADAMTS9 reduction.
  phenotype_term:
    preferred_term: Cleft palate
    term:
      id: HP:0000175
      label: Cleft palate
  frequency: OCCASIONAL
  evidence:
  - reference: PMID:20301637
    reference_title: "Peters Plus Syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      and, occasionally, cleft lip/palate and congenital heart defects
    explanation: >-
      GeneReviews describes cleft lip/palate as an occasional finding, which
      maps to the OCCASIONAL frequency band (5-29%) in the project's
      prose-to-enum mapping table.
- category: Cardiovascular
  name: Congenital Heart Defect
  description: >-
    Structural cardiac malformations occur in a minority of affected
    individuals; reported lesions include hypoplastic left heart, anomalous
    pulmonary venous return, and bicuspid pulmonary valve.
  phenotype_term:
    preferred_term: Abnormal heart morphology
    term:
      id: HP:0001627
      label: Abnormal heart morphology
  frequency: OCCASIONAL
  evidence:
  - reference: PMID:20301637
    reference_title: "Peters Plus Syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      and, occasionally, cleft lip/palate and congenital heart defects
    explanation: >-
      GeneReviews describes congenital heart defects as an occasional finding,
      which maps to the OCCASIONAL frequency band (5-29%) in the project's
      prose-to-enum mapping table.
- category: Renal
  name: Renal Anomalies
  description: >-
    Genitourinary malformations reported in a minority of cases, including
    multicystic dysplastic kidney, hydronephrosis, renal hypoplasia, and renal
    or ureteral duplication.
  phenotype_term:
    preferred_term: Multicystic kidney dysplasia
    term:
      id: HP:0000003
      label: Multicystic kidney dysplasia
  evidence:
  - reference: PMID:15912477
    reference_title: "Prenatal sonographic findings in Peters-plus syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      short limbs with broad extremities and unilateral multicystic kidney
    explanation: >-
      Documents unilateral multicystic dysplastic kidney in an autopsy-confirmed
      case of Peters plus syndrome.
genetic:
- name: B3GLCT
  notes: >-
    B3GLCT (13q12.3, formerly B3GALTL) encodes beta-1,3-glucosyltransferase.
    Biallelic loss-of-function variants, or one loss-of-function variant in
    trans with a contiguous 13q12.3 deletion including B3GLCT, cause PTRPLS. The
    recurrent splice-donor variant c.660+1G>A is by far the most common
    pathogenic allele; frameshift, nonsense, other splice, and rare
    activity-abolishing missense alleles account for the remainder. Because a
    contiguous-deletion allele is part of the mutational spectrum, copy-number
    analysis should accompany sequencing. B3GLCT variants are characteristically
    absent in isolated Peters anomaly and in partial "Peters-plus-like"
    phenotypes.
  gene_term:
    preferred_term: B3GLCT
    term:
      id: hgnc:20207
      label: B3GLCT
  presence: PRESENT
  relationship_type: CAUSATIVE
  variant_origin: GERMLINE
  evidence:
  - reference: PMID:16909395
    reference_title: "Peters Plus syndrome is caused by mutations in B3GALTL, a putative glycosyltransferase."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      we identified biallelic truncating mutations in the beta
      1,3-galactosyltransferase-like gene (B3GALTL) in all 20 tested patients
    explanation: >-
      Establishes B3GLCT (B3GALTL) as the single causal gene.
  - reference: PMID:23889335
    reference_title: "Novel B3GALTL mutations in classic Peters plus syndrome and lack of mutations in a large cohort of patients with similar phenotypes."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Consistent with previous reports, the c.660+1G>A mutation was the most
      common mutation identified, seen in eight of the nine patients and
      accounting for 55% of pathogenic alleles in this study and 69% of all
      reported pathogenic alleles
    explanation: >-
      Quantifies the dominance of the recurrent c.660+1G>A splice allele in the
      mutation spectrum.
  - reference: PMID:18798333
    reference_title: "Mutation analysis of B3GALTL in Peters Plus syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Mutations in B3GALTL were identified in all four patients with typical
      Peters Plus syndrome, while no mutations were found in the remaining four
      patients that demonstrated some but not all characteristic features of the
      syndrome.
    explanation: >-
      Shows that B3GLCT variants segregate with the complete syndrome and not
      with partial phenotypes.
  - reference: PMID:20301637
    reference_title: "Peters Plus Syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      either biallelic pathogenic variants in B3GLCT or compound heterozygosity
      for one pathogenic variant in B3GLCT and a contiguous gene deletion of
      13q12.3 that includes B3GLCT
    explanation: >-
      GeneReviews defines the two molecular genotype configurations that
      establish the diagnosis, including the contiguous-deletion allele.
  - reference: PMID:35170016
    reference_title: "First evidence of SOX2 mutations in Peters' anomaly: Lessons from molecular screening of 95 patients."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Unsurprisingly, B3GLCT and PAX6 were the most frequently implicated genes,
      respectively in syndromic and isolated PA.
    explanation: >-
      In the largest Peters anomaly cohort reported, B3GLCT is the leading gene
      for the syndromic form specifically, while PAX6 leads for isolated Peters
      anomaly.
variants:
- name: B3GLCT c.660+1G>A
  description: >-
    Recurrent intronic splice-donor variant (rs80338851), the single most common
    pathogenic B3GLCT allele; it accounts for roughly two-thirds to
    three-quarters of reported pathogenic alleles across cohorts and is found
    homozygously or in trans with a rarer second allele.
  gene:
    preferred_term: B3GLCT
    term:
      id: hgnc:20207
      label: B3GLCT
  clinical_significance: PATHOGENIC
  evidence:
  - reference: PMID:23889335
    reference_title: "Novel B3GALTL mutations in classic Peters plus syndrome and lack of mutations in a large cohort of patients with similar phenotypes."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      while two patients were homozygous for this mutation, the majority had a
      second rare pathogenic allele
    explanation: >-
      Describes the typical allelic configuration involving the recurrent
      splice-donor variant.
  - reference: PMID:18798333
    reference_title: "Mutation analysis of B3GALTL in Peters Plus syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      The previously reported common mutation, c.660 + 1G > A, accounted for 75%
      of the mutant alleles in our Peters Plus syndrome population.
    explanation: >-
      Independent cohort quantifying the allele frequency of the recurrent
      splice variant.
- name: B3GLCT c.755delC (p.Thr252fs)
  description: >-
    Frameshift variant in exon 9, first reported in 2019 in a newborn who was
    compound heterozygous for it and the recurrent c.660+1G>A allele.
    Illustrates the typical "one recurrent splice allele plus one private
    truncating allele" genotype.
  gene:
    preferred_term: B3GLCT
    term:
      id: hgnc:20207
      label: B3GLCT
  clinical_significance: PATHOGENIC
  evidence:
  - reference: PMID:31795264
    reference_title: "Contribution of a Novel B3GLCT Variant to Peters Plus Syndrome Discovered by a Combination of Next-Generation Sequencing and Automated Text Mining."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      helped us find two compound heterozygous variants of the B3GLCT gene, of
      which c.660+1G>A (rs80338851) was previously associated with the phenotype
      of Peters plus syndrome (PPS), while the second, NM_194318.3:c.755delC
      (p.T252fs), in exon 9 of the same gene was noted for the first time
    explanation: >-
      Reports the novel frameshift allele and the compound-heterozygous
      configuration with the recurrent splice variant.
diagnosis:
- name: B3GLCT Molecular Genetic Testing
  description: >-
    The diagnosis is established molecularly in a proband with suggestive
    clinical findings by identifying biallelic pathogenic B3GLCT variants, or
    one pathogenic variant in trans with a 13q12.3 contiguous gene deletion
    encompassing B3GLCT. Sequencing alone can miss the deletion allele, so
    copy-number analysis of 13q12.3 should accompany sequencing.
  evidence:
  - reference: PMID:20301637
    reference_title: "Peters Plus Syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      The diagnosis of PTRPLS is established in a proband with suggestive
      findings and either biallelic pathogenic variants in B3GLCT or compound
      heterozygosity for one pathogenic variant in B3GLCT and a contiguous gene
      deletion of 13q12.3 that includes B3GLCT identified by molecular genetic
      testing.
    explanation: >-
      GeneReviews diagnostic criterion.
  - reference: PMID:35170016
    reference_title: "First evidence of SOX2 mutations in Peters' anomaly: Lessons from molecular screening of 95 patients."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Causative genetic defects involving 12 genes and CNVs were identified for
      1/3 of patients.
    explanation: >-
      Reports diagnostic yield across the Peters anomaly spectrum using combined
      array, exome, genome, and panel testing. This is spectrum-wide yield, not
      PTRPLS test sensitivity, so it is recorded as partial support.
- name: Prenatal Ultrasound Recognition
  description: >-
    The syndrome can be suspected prenatally on the combination of
    microphthalmia with an echogenic anterior eye defect, short limbs with broad
    extremities, micrognathia and long philtrum, and renal anomalies. Corneal
    and anterior-segment findings are nonetheless hard to detect prenatally, so
    a normal scan does not exclude the diagnosis.
  evidence:
  - reference: PMID:15912477
    reference_title: "Prenatal sonographic findings in Peters-plus syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Ultrasound examination revealed microphthalmia and hyperechogenicity of
      the anterior part of the eye with a central defect, micrognathia and long
      philtrum, short limbs with broad extremities and unilateral multicystic
      kidney.
    explanation: >-
      Documents the prenatal sonographic constellation in an autopsy-confirmed
      case.
differential_diagnoses:
- name: Isolated Peters anomaly
  description: >-
    Peters anomaly occurring without the systemic features of PTRPLS. This is
    the single most important distinction for this entry: isolated Peters
    anomaly is a genetically distinct anterior-segment dysgenesis, and B3GLCT
    variants are consistently absent in it. Screening of 55 individuals with
    PTRPLS-like phenotypes or isolated Peters anomaly identified no B3GLCT
    variants, and in the largest Peters anomaly cohort reported the leading gene
    for isolated disease is PAX6 rather than B3GLCT.
  distinguishing_features:
  - Absence of disproportionate rhizomelic short stature, brachydactyly, and broad hands and feet
  - Absence of the characteristic facies (exaggerated cupid's-bow upper lip, prominent forehead, hypertelorism)
  - Absence of cleft lip and/or palate and of developmental delay
  - Absence of biallelic loss-of-function B3GLCT variants
  - Often unilateral and milder ocular disease, whereas PTRPLS ocular involvement is typically bilateral
  - Associated instead with PAX6, PITX2, PITX3, FOXE3, FOXC1, CYP1B1, and SOX2 variants
  evidence:
  - reference: PMID:23889335
    reference_title: "Novel B3GALTL mutations in classic Peters plus syndrome and lack of mutations in a large cohort of patients with similar phenotypes."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      We also report the absence of B3GALTL mutations in 55 cases of PPS-like
      phenotypes or isolated Peters anomaly, further establishing the strong
      association of B3GALTL mutations with classic PPS only.
    explanation: >-
      Direct cohort evidence that B3GLCT is not implicated in isolated Peters
      anomaly, separating it from PTRPLS.
  - reference: PMID:35170016
    reference_title: "First evidence of SOX2 mutations in Peters' anomaly: Lessons from molecular screening of 95 patients."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Several genes are involved in syndromic or isolated PA (B3GLCT, PAX6,
      PITX3, FOXE3, CYP1B1).
    explanation: >-
      Enumerates the genetically distinct causes of Peters anomaly outside the
      B3GLCT syndromic entity.
  - reference: PMID:35170016
    reference_title: "First evidence of SOX2 mutations in Peters' anomaly: Lessons from molecular screening of 95 patients."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Unsurprisingly, B3GLCT and PAX6 were the most frequently implicated genes,
      respectively in syndromic and isolated PA.
    explanation: >-
      Assigns B3GLCT to syndromic and PAX6 to isolated Peters anomaly, the
      cleanest statement of the split.
- name: Peters-plus-like syndrome
  description: >-
    Individuals who display a PTRPLS-like clinical pattern but lack diagnostic
    biallelic B3GLCT variants. Some carry B3GLCT missense changes, but
    functional testing shows these retain enzymatic activity, so the underlying
    cause is not loss of the Glc-beta1,3-Fuc disaccharide. Copy-number variants
    involving other loci can produce the pattern: a de novo 1.6 Mb deletion
    spanning PEX2 and ZFHX4 was reported in a patient with a Peters-plus-like
    phenotype.
  distinguishing_features:
  - Incomplete or atypical clinical constellation relative to classic PTRPLS
  - No biallelic loss-of-function B3GLCT genotype
  - B3GLCT alleles, when present, retain catalytic activity in vitro
  - May be explained by copy-number variants at other loci, such as a PEX2-ZFHX4 deletion
  evidence:
  - reference: PMID:34058199
    reference_title: "Peters plus syndrome mutations affect the function and stability of human beta1,3-glucosyltransferase."
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: >-
      In contrast, B3GLCT with PTRPLS-like mutations retained enzymatic
      activity, although some showed a minor destabilizing effect.
    explanation: >-
      Functional data distinguishing true PTRPLS alleles from those seen in
      partial phenotypes.
  - reference: PMID:40650233
    reference_title: "Novel Genetic Variants and Clinical Profiles in Peters Anomaly Spectrum Disorders."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      In the first patient, a heterozygous ~1.6 Mb deletion was detected,
      spanning the genes PEX2 and ZFHX4
    explanation: >-
      Documents a non-B3GLCT copy-number cause of a Peters-plus-like
      presentation.
  - reference: PMID:40650233
    reference_title: "Novel Genetic Variants and Clinical Profiles in Peters Anomaly Spectrum Disorders."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      with the first patient displaying both ocular and systemic anomalies as in
      a Peters plus-like syndrome phenotype, while the second patient had
      isolated ocular manifestations as in a PA type 1 phenotype
    explanation: >-
      Illustrates the clinical separation of Peters-plus-like from isolated
      Peters anomaly within the same cohort.
treatments:
- name: Multidisciplinary Supportive Care
  description: >-
    There is no disease-modifying therapy - no B3GLCT replacement, substrate,
    chaperone, gene, or RNA therapy exists. Management is supportive and
    multidisciplinary, coordinating ophthalmology, orthopedics, rehabilitation
    therapies, educational support, a cleft lip/palate team, and social services
    including planning the transition from pediatric to adult care.
  action_category: THERAPEUTIC
  treatment_term:
    preferred_term: multidisciplinary supportive care
    term:
      id: NCIT:C15747
      label: Supportive Care
  evidence:
  - reference: PMID:20301637
    reference_title: "Peters Plus Syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Multidisciplinary care by specialists in relevant fields including
      ophthalmology to manage eye anomalies; low vision services as needed;
      orthopedics, physical therapy, and occupational therapy to determine need
      for adaptive devices to address mobility and fine motor needs; educational
      support for developmental delay and/or intellectual disability; cleft
      lip/palate team; social services to develop a plan for transition from
      pediatric care to adult care.
    explanation: >-
      GeneReviews management recommendation defining the supportive-care model.
- name: Ophthalmologic Surgical Management
  description: >-
    Surgical management of the anterior-segment anomaly, which may include
    penetrating keratoplasty or keratoprosthesis for visually significant
    opacity, lensectomy, and glaucoma procedures. Decisions are individualized:
    severe bilateral dysgenesis, glaucoma, graft failure, and retinal
    complications can limit the benefit, and surgery is sometimes deliberately
    deferred.
  action_category: THERAPEUTIC
  treatment_term:
    preferred_term: ophthalmologic surgical procedure
    term:
      id: NCIT:C15331
      label: Ophthalmologic Surgical Procedure
  therapeutic_modality: SURGERY
  target_phenotypes:
  - preferred_term: Corneal opacity
    term:
      id: HP:0007957
      label: Corneal opacity
  - preferred_term: Glaucoma
    term:
      id: HP:0000501
      label: Glaucoma
  notes: >-
    Reported surgical experience is drawn largely from the broader Peters
    anomaly spectrum rather than from molecularly confirmed PTRPLS cohorts; no
    PTRPLS-specific comparative surgical trial exists.
  evidence:
  - reference: PMID:20301637
    reference_title: "Peters Plus Syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Multidisciplinary care by specialists in relevant fields including
      ophthalmology to manage eye anomalies; low vision services as needed
    explanation: >-
      GeneReviews assigns management of the eye anomalies to ophthalmology, with
      low-vision services as adjunct.
- name: Ophthalmologic Surveillance for Glaucoma
  description: >-
    Because glaucoma can develop at any age and threatens residual vision,
    GeneReviews recommends intraocular-pressure and ophthalmologic surveillance
    in early infancy, again at three and six months of age, and at least every
    six months thereafter. Early infancy is also the critical window for
    detecting and treating deprivation amblyopia.
  action_category: MONITORING
  treatment_term:
    preferred_term: ophthalmologic surveillance
    term:
      id: NCIT:C38060
      label: Eye Examination
  notes: >-
    Modeled as a MONITORING action rather than a therapy, so it deliberately
    carries no target_phenotypes / target_mechanisms link: surveillance detects
    glaucoma, it does not act on the glaucoma mechanism. The phenotype it
    watches for is named in the description and is curated separately under
    phenotypes.
  evidence:
  - reference: PMID:20301637
    reference_title: "Peters Plus Syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      monitor emergence of new ophthalmologic manifestations including glaucoma
      in early infancy, then at age three months and age six months, and a
      minimum of every six months thereafter
    explanation: >-
      GeneReviews surveillance schedule for glaucoma.
- name: Physical and Occupational Therapy
  description: >-
    Physical and occupational therapy, coordinated with orthopedics, to address
    mobility and fine-motor needs arising from short stature, rhizomelia, and
    hand anomalies, and to determine the need for adaptive devices.
  action_category: THERAPEUTIC
  treatment_term:
    preferred_term: physical therapy
    term:
      id: NCIT:C15302
      label: Physical Therapy
  therapeutic_modality: BEHAVIORAL
  evidence:
  - reference: PMID:20301637
    reference_title: "Peters Plus Syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      orthopedics, physical therapy, and occupational therapy to determine need
      for adaptive devices to address mobility and fine motor needs
    explanation: >-
      GeneReviews recommendation for rehabilitation therapy.
- name: Cleft Lip and Palate Repair
  description: >-
    Surgical repair and longitudinal management of cleft lip and/or palate by a
    dedicated cleft team, when clefting is present, together with feeding,
    speech, dental, and audiology support.
  action_category: THERAPEUTIC
  treatment_term:
    preferred_term: surgical procedure
    term:
      id: NCIT:C15329
      label: Surgical Procedure
  therapeutic_modality: SURGERY
  target_phenotypes:
  - preferred_term: Cleft palate
    term:
      id: HP:0000175
      label: Cleft palate
  - preferred_term: Cleft upper lip
    term:
      id: HP:0000204
      label: Cleft upper lip
  evidence:
  - reference: PMID:20301637
    reference_title: "Peters Plus Syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      cleft lip/palate team
    explanation: >-
      GeneReviews assigns cleft management to a dedicated multidisciplinary
      team.
- name: Educational and Developmental Support
  description: >-
    Individualized educational support and early-intervention services for
    developmental delay and/or intellectual disability, with monitoring of
    educational, neurobehavioral, and musculoskeletal needs over time.
  action_category: THERAPEUTIC
  treatment_term:
    preferred_term: educational and developmental support
    term:
      id: NCIT:C15747
      label: Supportive Care
  therapeutic_modality: BEHAVIORAL
  target_phenotypes:
  - preferred_term: Global developmental delay
    term:
      id: HP:0001263
      label: Global developmental delay
  evidence:
  - reference: PMID:20301637
    reference_title: "Peters Plus Syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Monitor the individual's response to supportive care (including
      educational, neurobehavioral, and musculoskeletal needs)
    explanation: >-
      GeneReviews surveillance recommendation covering the developmental and
      educational domain.
- name: Genetic Counseling
  description: >-
    Counseling on autosomal recessive recurrence risk. Once the familial B3GLCT
    variants are known, carrier testing for at-risk relatives and prenatal or
    preimplantation genetic testing are available. Counseling should note that
    the observed sibling risk at birth is below the theoretical 25% because of
    increased fetal loss.
  action_category: COUNSELING_INFORMATIONAL
  treatment_term:
    preferred_term: genetic counseling
    term:
      id: NCIT:C15240
      label: Genetic Counseling
  evidence:
  - reference: PMID:20301637
    reference_title: "Peters Plus Syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Once the pathogenic variants involving B3GLCT have been identified in an
      affected family member, carrier testing for at-risk relatives and
      prenatal/preimplantation genetic testing for PTRPLS are possible.
    explanation: >-
      GeneReviews genetic-counseling recommendation.
animal_models:
- name: B3glct knockout mouse
  species: Mouse
  genotype: B3glct knockout
  description: >-
    Two independent B3glct knockout alleles reproduce craniofacial and skeletal
    abnormalities comparable to human PTRPLS, together with highly penetrant
    hydrocephalus, white coat spotting, and soft-tissue syndactyly. Genetic and
    biochemical dissection attributes the hydrocephalus and white spotting to
    loss of ADAMTS20, the eye abnormalities to partial reduction of ADAMTS9, and
    the cleft palate to both. This is the most informative whole-animal model of
    the syndrome.
  genes:
  - preferred_term: B3GLCT
    term:
      id: hgnc:20207
      label: B3GLCT
  evidence:
  - reference: PMID:31600785
    reference_title: "ADAMTS9 and ADAMTS20 are differentially affected by loss of B3GLCT in mouse model of Peters plus syndrome."
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: >-
      we developed and characterized two mouse B3glct knockout alleles
    explanation: >-
      Establishes the mouse knockout as the principal in vivo model.
  - reference: PMID:31600785
    reference_title: "ADAMTS9 and ADAMTS20 are differentially affected by loss of B3GLCT in mouse model of Peters plus syndrome."
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: >-
      In addition, we observed highly penetrant hydrocephalus, white spotting
      and soft tissue syndactyly.
    explanation: >-
      Notes mouse-specific findings that extend beyond the recognized human
      phenotype and limit one-to-one phenotype transfer.
- name: b3glcta/b3glctb double-knockout zebrafish
  species: Zebrafish
  genotype: b3glcta/b3glctb double knockout
  description: >-
    TALEN-generated single and double knockouts of the two zebrafish B3GLCT
    orthologs abolish in vitro b3glct activity, yet double-homozygous fish
    develop normally. Transcriptome analysis identified 483 differentially
    regulated transcripts that may reflect compensation. The model therefore
    does not recapitulate the human disease and is of limited value for
    phenotype studies despite conserved enzyme function.
  genes:
  - preferred_term: B3GLCT
    term:
      id: hgnc:20207
      label: B3GLCT
  evidence:
  - reference: PMID:28926587
    reference_title: "Functional characterization of zebrafish orthologs of the human Beta 3-Glucosyltransferase B3GLCT gene mutated in Peters Plus Syndrome."
    supports: REFUTE
    evidence_source: MODEL_ORGANISM
    snippet: >-
      Surprisingly, b3glct-/- homozygous fish developed normally.
    explanation: >-
      The zebrafish null does not reproduce the human phenotype, refuting its
      utility as a disease model.
  - reference: PMID:28926587
    reference_title: "Functional characterization of zebrafish orthologs of the human Beta 3-Glucosyltransferase B3GLCT gene mutated in Peters Plus Syndrome."
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: >-
      Extracts from double homozygous b3glct-/- embryos demonstrated complete
      loss of in vitro b3glct activity.
    explanation: >-
      Confirms the knockout is a true enzymatic null, so the absent phenotype is
      not a technical failure of gene targeting.
progression:
- phase: Prenatal
  notes: >-
    The molecular defect acts during embryogenesis, so the malformations are
    congenital rather than acquired. Affected pregnancies carry an increased
    risk of miscarriage and of second- and third-trimester fetal loss, so the
    observed proportion of affected liveborn siblings is below the theoretical
    25% recurrence risk.
  evidence:
  - reference: PMID:20301637
    reference_title: "Peters Plus Syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      However, at birth the risk to sibs of a proband of being affected is less
      than 25% because there is an increased chance for miscarriages and second-
      and third-trimester loss of affected fetuses.
    explanation: >-
      GeneReviews documents excess prenatal lethality as a feature of the
      natural history.
- phase: Infancy and childhood
  notes: >-
    Structural lesions are congenital and largely non-progressive, but their
    consequences evolve. Early infancy is the critical window for visual-axis
    clearing and amblyopia prevention; glaucoma may emerge at any point and
    requires the GeneReviews surveillance schedule; feeding, speech, dental, and
    hearing consequences of clefting change with age; and short stature and
    developmental limitations become more apparent as developmental demands
    increase.
  evidence:
  - reference: PMID:20301637
    reference_title: "Peters Plus Syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      monitor emergence of new ophthalmologic manifestations including glaucoma
      in early infancy, then at age three months and age six months, and a
      minimum of every six months thereafter
    explanation: >-
      The surveillance schedule reflects the expectation that new ophthalmologic
      manifestations emerge over the course of infancy and childhood.
discussions:
- discussion_id: ptrpls_zebrafish_null_no_phenotype
  prompt: >-
    Why does complete loss of b3glct in zebrafish produce no phenotype when the
    orthologous human loss of function causes a severe multisystem malformation
    syndrome, and what compensates?
  kind: HUMAN_MODEL_MISMATCH
  status: OPEN
  attaches_to:
  - pathophysiology#Impaired ER Quality Control and Secretion of TSR-Containing Proteins
  rationale: >-
    Zebrafish b3glcta/b3glctb double nulls have no detectable enzyme activity
    yet develop normally, while B3glct knockout mice reproduce much of the human
    syndrome and human biallelic loss is severe. The mismatch is not a failure
    of gene conservation - the zebrafish enzymes are catalytically equivalent to
    human B3GLCT - so it points to a species-specific compensatory route for TSR
    folding, or to a difference in the dosage sensitivity of the ADAMTS targets.
    Identifying that compensation would name a candidate therapeutic bypass of
    the human defect, so this is a mechanistically loaded rather than incidental
    discrepancy. It also means negative zebrafish results must not be treated as
    evidence against a proposed PTRPLS mechanism.
  proposed_experiments:
  - experiment_id: ptrpls_zebrafish_compensation_transcriptome
    name: Characterize the zebrafish compensatory transcriptome
    description: >-
      Follow up the 483 differentially regulated transcripts identified in
      b3glct-null embryos to test whether any encode an alternative
      glucosyltransferase or TSR chaperone that can substitute for b3glct, then
      test whether forced expression of the human ortholog of that factor
      rescues TSR secretion in B3GLCT-null human cells.
    supporting_outcome:
    - Identification of an upregulated factor whose human ortholog restores TSR secretion in B3GLCT-null human cells would support species-specific enzymatic or chaperone compensation.
    refuting_outcome:
    - Failure of any candidate to rescue human TSR secretion would argue that the difference lies in substrate dosage sensitivity rather than in a compensating factor.
  - experiment_id: ptrpls_cross_species_adamts_secretion
    name: Cross-species ADAMTS secretion comparison
    description: >-
      Quantify secretion of orthologous ADAMTS9 and ADAMTS20 proteins from
      B3GLCT-null human, mouse, and zebrafish cells to determine whether the
      species difference lies in the folding requirement of the substrate rather
      than in a compensating enzyme.
    supporting_outcome:
    - Preserved ADAMTS secretion from zebrafish nulls alongside impaired secretion from human and mouse nulls would localize the difference to the substrate rather than the pathway.
    refuting_outcome:
    - Equally impaired ADAMTS secretion across all three species would place the divergence downstream of secretion, in tissue-level tolerance of reduced ADAMTS activity.
  evidence:
  - reference: PMID:28926587
    reference_title: "Functional characterization of zebrafish orthologs of the human Beta 3-Glucosyltransferase B3GLCT gene mutated in Peters Plus Syndrome."
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: >-
      The presented data show that both sequence and function of B3GLCT/b3glct
      genes is conserved in vertebrates. At the same time, complete b3glct
      deficiency in zebrafish appears to be inconsequential and possibly
      compensated for by a yet unknown mechanism.
    explanation: >-
      States the mismatch and the compensation hypothesis explicitly.
  - reference: PMID:31600785
    reference_title: "ADAMTS9 and ADAMTS20 are differentially affected by loss of B3GLCT in mouse model of Peters plus syndrome."
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: >-
      The mouse B3glct mutants developed craniofacial and skeletal
      abnormalities comparable to PTRPLS.
    explanation: >-
      Contrasting mouse result that makes the zebrafish outcome a genuine
      cross-species discrepancy rather than a general model limitation.
- discussion_id: ptrpls_target_selectivity_gap
  prompt: >-
    Which of the 49 POFUT2/B3GLCT target proteins actually mediate each human
    PTRPLS manifestation, and why are only a subset dosage-sensitive to loss of
    the terminal glucose?
  kind: KNOWLEDGE_GAP
  status: OPEN
  attaches_to:
  - pathophysiology#Reduced ADAMTS9 and ADAMTS20 Function in the Extracellular Matrix
  rationale: >-
    Mouse genetics implicates ADAMTS20 and ADAMTS9 for hydrocephalus, white
    spotting, cleft palate, and eye defects, but the human phenotype includes
    features not explained by these two targets (rhizomelic short stature,
    brachydactyly, the characteristic facies, congenital heart and renal
    defects). The correspondence is not uniform in the other direction either:
    hydrocephalus, initially conspicuous as a mouse finding, is in fact
    documented in human PTRPLS fetuses at postmortem, so it appears to be a
    genuinely shared severe/prenatal feature that liveborn clinical series
    under-report - whereas white coat spotting has no human counterpart at all.
    Systematic mapping of which targets are under-secreted in patient cells and
    which tissues depend on each would turn the pathway model into a
    per-phenotype mechanism, and would clarify which apparent species
    differences are real versus ascertainment artifacts.
  evidence:
  - reference: PMID:31600785
    reference_title: "ADAMTS9 and ADAMTS20 are differentially affected by loss of B3GLCT in mouse model of Peters plus syndrome."
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: >-
      Previous studies suggested that O-linked fucose is essential for folding
      and secretion of POFUT2-modified proteins and that B3GLCT-mediated
      extension to the disaccharide is essential for only a subset of targets.
    explanation: >-
      States the selective-dependency problem that this gap addresses.
  - reference: PMID:25544610
    reference_title: "Peters plus syndrome mutations disrupt a noncanonical ER quality-control mechanism."
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: >-
      Although 49 putative targets are known, the function of the disaccharide
      and its role in PPS remain unexplored.
    explanation: >-
      Frames the size of the target repertoire against which per-phenotype
      attribution is still missing.
- discussion_id: ptrpls_no_clinical_glycosylation_biomarker
  prompt: >-
    Can the loss of glucose on properdin thrombospondin type-1 repeats be
    developed into a deployable clinical biomarker for Peters plus syndrome and
    for measuring response to any future therapy?
  kind: KNOWLEDGE_GAP
  status: OPEN
  attaches_to:
  - pathophysiology#Absent Glucose-beta-1,3-Fucose Disaccharide on Thrombospondin Type-1 Repeats
  rationale: >-
    Unlike the N-glycosylation CDGs, PTRPLS has no routine screening assay -
    serum transferrin isoelectric focusing is normal - so diagnosis is entirely
    genotype-driven. The properdin glycoform assay is a validated research-grade
    biochemical readout of functional null status in patient material, but it
    has not been converted into an available clinical test. Without one there is
    no way to assay the functional consequence of a B3GLCT variant of uncertain
    significance, and no pharmacodynamic endpoint for a future therapy.
  evidence:
  - reference: PMID:18199743
    reference_title: "Peters Plus syndrome is a new congenital disorder of glycosylation and involves defective Omicron-glycosylation of thrombospondin type 1 repeats."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      We have established a sensitive immunopurification-mass spectrometry
      method, using multiple reaction monitoring, to analyze Omicron-fucosyl
      glycans.
    explanation: >-
      Describes the research assay that would need to be translated into a
      clinical test.
notes: >-
  Scope note. This entry covers Peters plus syndrome, the B3GLCT-related
  syndromic entity (MONDO:0009856, OMIM 261540). It deliberately does NOT cover
  isolated Peters anomaly, which is a genetically distinct anterior-segment
  dysgenesis associated with PAX6, PITX2, PITX3, FOXE3, FOXC1, CYP1B1, and SOX2
  and in which B3GLCT variants are consistently absent; that distinction is
  captured under differential_diagnoses. Related dismech entries covering the
  isolated anterior-segment side of the spectrum are
  FOXE3_Anterior_Segment_Dysgenesis and Axenfeld-Rieger_syndrome.

  Correction to the source issue. GitHub issue 7706 described this disorder as
  "B4GALT1-related". That is incorrect: B4GALT1 causes CDG type IId, a distinct
  disorder. The causal gene here is B3GLCT (hgnc:20207, formerly B3GALTL), as
  confirmed by the MONDO:0009856 record (relationship RO:0004003 HGNC:20207),
  the OMIM 261540 xref, and GeneReviews. The NEC preflight was run against
  MONDO:0009856 before any deep-research content was used.

  Frequencies deliberately omitted. Apart from the three OCCASIONAL bands
  supported directly by the GeneReviews word "occasionally", no phenotype
  frequency is asserted. Two numbers that circulate in the literature were
  specifically rejected: the 30-70% glaucoma frequency and the 2.2-3.1 per
  100,000 birth prevalence both describe the broader Peters anomaly spectrum,
  not molecularly confirmed Peters plus syndrome, and a roughly 33%
  cardiac-malformation figure derives from a very small, ascertainment-biased
  case literature.

  Prevalence. Orphanet (ORPHA:709) is the natural structured source, but the
  pinned Orphadata bulk XML in this repository no longer matches its manifest
  checksum, so no ORPHA_709 cache record could be generated. Only the
  qualitative rarity band is therefore recorded.

  Deep research. Edison/falcon was run for this entry
  (research/Peters_Plus_Syndrome-deep-research-falcon.md, 730 s, 19 citations).
  Its NEC identity anchors matched (B3GLCT, MONDO:0009856, OMIM 261540, explicit
  separation from isolated Peters anomaly). The report contributed the Vasudevan
  2015 noncanonical-ER-quality-control mechanism (PMID:25544610), the Chesneau
  2022 Peters anomaly cohort (PMID:35170016), the Delas 2025 Peters-plus-like
  CNV case (PMID:40650233), and the c.755delC variant report (PMID:31795264).
  Its claim that no validated B3glct-null mouse exists was contradicted by
  independent PubMed searching and is not reflected in this entry; PMID:31600785
  describes exactly such a model.
📚

References & Deep Research

References

1
PMID:20301637
Peters Plus Syndrome.
No top-level findings curated for this source.

Deep Research

1
Falcon ▸
Disease Characteristics Research Template
Edison Scientific Literature 19 citations 2026-08-01T17:20:15.024669

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: Peters plus syndrome
  • MONDO ID: (if available)
  • Category: Mendelian

Research Objectives

Please provide a comprehensive research report on Peters plus syndrome 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
  • RNA-based therapies (ASOs, siRNA, mRNA therapies) > Search first: ClinicalTrials.gov, FDA approvals, PubMed
  • 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 NCIT (NCI Thesaurus) clinical-intervention 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, NCIT, 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 (NCIT terms) - Evidence items with PMIDs and exact abstract quotes - Epidemiology, prognosis, diagnostic, and prevention information - Animal model descriptions with phenotype recapitulation details

Peters plus syndrome: comprehensive disease-characteristics report

Executive summary

Peters plus syndrome (PPS) is an ultra-rare, congenital, autosomal-recessive multisystem developmental disorder and congenital disorder of O-glycosylation. Molecularly confirmed PPS requires biallelic pathogenic variants in B3GLCT—historically B3GALTL—together with anterior-segment dysgenesis, usually Peters anomaly, and systemic abnormalities such as short stature/short limbs, brachydactyly, cleft lip/palate, characteristic craniofacial features, and variable neurodevelopmental impairment. It must be distinguished from isolated Peters anomaly and from “Peters-plus-like syndrome,” in which the clinical pattern is similar but biallelic B3GLCT variants are absent. Open Targets identifies B3GLCT as the single associated target for MONDO:0009856, supported by human genetic literature including PMIDs 16909395, 20301637, and 23889335. (OpenTargets Search: Peters plus syndrome, totonzuranska2019contributionofa pages 1-3, delas2025novelgeneticvariants pages 2-3)

The best-established mechanism is loss of an endoplasmic-reticulum glycosylation/quality-control pathway. POFUT2 first O-fucosylates correctly folded thrombospondin type-1 repeats (TSRs); B3GLCT then adds glucose to form Glcβ1-3Fuc. Loss of B3GLCT disrupts folding, stabilization, and secretion of a subset of TSR-containing extracellular proteins. There is currently no disease-modifying therapy; care is multidisciplinary, developmental, surgical, and complication-directed. (vasudevan2015petersplussyndrome pages 1-3)

1. Disease information

Definition and classification

PPS is a Mendelian syndromic anterior-segment dysgenesis and congenital glycosylation disorder. Its defining ocular lesion, Peters anomaly, comprises congenital central corneal opacity with abnormal separation/adhesion among cornea, iris, and sometimes lens. Systemic involvement distinguishes PPS from most isolated Peters anomaly. (totonzuranska2019contributionofa pages 1-3, delas2025novelgeneticvariants pages 2-3)

Key identifiers

  • MONDO: MONDO:0009856.
  • OMIM phenotype: 261540, as reported in the literature.
  • Causal gene: B3GLCT, Ensembl ENSG00000187676; former symbol B3GALTL.
  • Orphanet: PPS is registered as a rare disease, although a numeric ORPHA identifier was not independently verified in the retrieved evidence.
  • ICD-10/ICD-11 and MeSH: no PPS-specific code was verified. Coding generally requires broader congenital ocular-malformation, cleft, short-stature, or genetic-syndrome categories; local terminology-service validation is recommended.

Common names include Peters plus syndrome, Peters’-plus syndrome, B3GLCT-related Peters plus syndrome, and older B3GALTL-related Peters plus syndrome. “Peters-plus-like syndrome” should not be treated as a synonym for genetically confirmed PPS. (totonzuranska2019contributionofa pages 1-3, delas2025novelgeneticvariants pages 2-3)

The evidence summarized here is aggregated disease-level evidence from peer-reviewed cohorts, case reports, mechanistic experiments, and curated databases—not individual-level EHR data.

2. Etiology, risk, protection, and environment

Causal factor

The primary cause is biallelic germline pathogenic variation in B3GLCT, producing autosomal-recessive loss of enzyme function. Affected people are usually homozygous or compound heterozygous; unaffected parents generally carry one allele each. The 2019 molecular case report identified compound heterozygosity for the known canonical splice variant NM_194318.3:c.660+1G>A (rs80338851) and novel frameshift c.755delC, p.Thr252fs. Its abstract states: “PPS, a very rare subtype of ASD, is a glycosylation disorder, where the dysfunctional B3GLCT gene product, O-fucose-specific β-1,3-glucosyltransferase, is ineffective in providing a noncanonical quality control system for proper protein folding in cells.” Published November 2019; DOI: https://doi.org/10.3390/ijms20236006. (totonzuranska2019contributionofa pages 1-3)

Other documented pathogenic classes include splice-disrupting, nonsense, frameshift, and likely other loss-of-function alleles. Most disease-associated alleles are expected to impair transcript processing or truncate/inactivate the protein. Exact ACMG classifications and population frequencies should be retrieved variant-by-variant from current ClinVar and gnomAD releases before database loading; the retrieved papers did not provide reliable contemporary allele frequencies for every allele.

Risk and protective factors

The major risk factor is having two carrier parents. For such a couple, each pregnancy has the standard autosomal-recessive probabilities: 25% affected, 50% carrier, and 25% unaffected/non-carrier. Consanguinity can increase the probability that both parents carry the same rare allele, but PPS occurs in non-consanguineous families as well.

No validated susceptibility loci, modifier genes, protective variants, environmental triggers, dietary or lifestyle risks, infectious causes, toxins, occupational exposures, or gene–environment interactions are established. Maternal age, paternal age, sex, smoking, alcohol, diet, and infection should not be represented as PPS causal factors without separate evidence. Because the initiating defect is germline and developmental, lifestyle modification cannot prevent disease in a genetically affected embryo.

3. Phenotypes

Core phenotype and timing

PPS begins prenatally and is clinically congenital. The core constellation includes:

  • Peters anomaly/anterior-segment dysgenesis: congenital corneal opacity with iridocorneal or corneolenticular adhesions; often bilateral and severe in syndromic disease. Suggested HPO: Corneal opacity (HP:0000659), Anterior segment dysgenesis, Peters anomaly, Iridocorneal adhesion.
  • Visual impairment: caused by opacity, refractive error, cataract where present, sensory-deprivation amblyopia, and secondary glaucoma. Suggested HPO: Visual impairment, Amblyopia, Cataract (HP:0000519), Glaucoma (HP:0000501).
  • Disproportionate short stature/short limbs and brachydactyly: congenital skeletal pattern with persistent growth restriction. Suggested HPO: Short stature (HP:0004322), Brachydactyly (HP:0001156), Short limbs.
  • Cleft lip with or without cleft palate: congenital; feeding, speech, dental, hearing, and surgical consequences vary. Suggested HPO: Cleft upper lip (HP:0000204), Cleft palate (HP:0000175).
  • Characteristic craniofacial appearance: variable facial dysmorphism, often including a prominent forehead, short/upslanting palpebral fissures, broad nasal bridge, and Cupid-bow upper lip in historical descriptions.
  • Developmental delay/intellectual disability: variable from mild to severe; speech and motor development may both be affected. Suggested HPO: Global developmental delay (HP:0001263), Intellectual disability (HP:0001249).

Additional reported manifestations include microcephaly or structural CNS anomalies, seizures, hypotonia, hearing impairment, congenital external/middle-ear anomalies, congenital heart defects, vertebral abnormalities, genitourinary malformations, feeding problems, and dental/oral abnormalities. A syndrome-focused oral-health report estimated cardiac malformations in approximately 33%, but this is based on a very small and ascertainment-biased literature and should be stored as a low-confidence qualitative frequency rather than a population estimate. (viga2018petersplussyndromeoral pages 2-4)

For broader Peters anomaly—not specifically molecularly confirmed PPS—glaucoma has been reported in 30–70%. This range is clinically useful for surveillance but must not be loaded as a PPS-specific frequency. (delas2025novelgeneticvariants pages 2-3)

Course and quality of life

Structural malformations are congenital and generally non-remitting. Their consequences are chronic and may evolve: amblyopia becomes less reversible as the visual-development window closes; glaucoma may arise later; short stature persists; developmental demands expose learning and adaptive limitations; cleft-associated feeding, speech, dental, and hearing issues change with age. Formal EQ-5D, SF-36, PROMIS, disease-specific quality-of-life, survival, and disability-weight studies were not found. Nevertheless, visual impairment, repeated anesthesia/surgery, communication difficulties, educational needs, and dependence in daily activities can substantially affect patients and caregivers. (viga2018petersplussyndromeoral pages 2-4, delas2025novelgeneticvariants pages 3-6)

4. Genetic and molecular information

B3GLCT encodes beta-3-glucosyltransferase, also described as O-fucose-specific β1,3-glucosyltransferase. The disease alleles are germline; PPS is not a somatic or cancer-associated condition. Current evidence supports loss of function rather than gain of function, dominant-negative action, or haploinsufficiency. Heterozygous carriers are ordinarily unaffected.

The strongest directly documented variants in retrieved evidence are:

  • c.660+1G>A; rs80338851: canonical donor-splice alteration, recurrent pathogenic PPS allele.
  • NM_194318.3:c.755delC, p.Thr252fs: frameshift first reported in a compound-heterozygous newborn in 2019.
  • Other splice, nonsense, and truncating alleles are reported across the literature, including a previously published novel nonsense allele referenced in later PA-spectrum work. (totonzuranska2019contributionofa pages 1-3, delas2025novelgeneticvariants pages 14-15)

No reproducible modifier gene, disease-specific epigenetic signature, pathogenic methylation abnormality, anticipation, or large recurrent chromosomal rearrangement is established for classic PPS. A Peters-plus-like phenotype caused by other genes or copy-number changes should be classified separately rather than broadening B3GLCT-PPS indiscriminately. (delas2025novelgeneticvariants pages 2-3, delas2025novelgeneticvariants pages 13-14)

5. Environmental information

No environmental, lifestyle, occupational, toxic, radiological, nutritional, or infectious factor is known to cause classic PPS. Such factors may affect general pregnancy or surgical health but are not part of PPS etiology. No environmental protective intervention has been shown to reduce penetrance or severity in a fetus with biallelic pathogenic B3GLCT variants.

6. Mechanism and pathophysiology

Causal chain

  1. Upstream genetic trigger: biallelic B3GLCT loss-of-function variants reduce or abolish active ER-localized glucosyltransferase.
  2. Substrate recognition: as TSR-containing secreted proteins fold in the ER, POFUT2 recognizes properly folded TSRs and adds O-linked fucose to serine/threonine in the TSR consensus sequence.
  3. B3GLCT reaction: B3GLCT adds glucose in β1-3 linkage to the O-fucose, forming Glcβ1-3Fuc.
  4. Quality-control failure: without B3GLCT, O-fucosylated TSRs lack glucose extension. Folding, stabilization, ER exit, and secretion are impaired for a subset of TSR proteins.
  5. Developmental extracellular-matrix/signaling dysfunction: affected proteins include members of thrombospondin and ADAMTS/ADAMTS-like families and other TSR-bearing proteins involved in extracellular matrix, morphogenesis, and tissue organization.
  6. Clinical manifestations: disturbed anterior-eye, craniofacial, skeletal, neural, cardiac, and other organ development produces the congenital PPS phenotype.

Vasudevan et al. showed that B3GLCT is ER-localized and forms the Glcβ1-3Fuc disaccharide on TSRs. They identified 49 TSR-containing proteins, including TSP1/TSP2 and ADAMTS/ADAMTSL proteins. Patient serum showed complete loss of glucose from properdin TSRs, providing a human biochemical readout of functional null status. POFUT2 loss impaired secretion of all tested targets, whereas B3GLCT loss affected a subset, indicating overlapping but non-identical roles. Published February 2015; DOI: https://doi.org/10.1016/j.cub.2014.11.049. (vasudevan2015petersplussyndrome pages 1-3)

Suggested annotations include GO:0005783 endoplasmic reticulum, GO:0006457 protein folding, protein O-linked glycosylation, ER protein-quality control, protein secretion, extracellular-matrix organization, and embryonic morphogenesis. Relevant candidate cell types include neural crest cells, corneal endothelial/stromal cells, periocular mesenchyme, craniofacial mesenchyme, chondrocytes, and cardiogenic neural-crest derivatives. These cell-level links are biologically plausible but are less directly resolved than the biochemical pathway.

No disease-specific immune, inflammatory, ischemic, fibrotic, mitochondrial-energy, lipidomic, or metabolomic mechanism is established. No validated single-cell, spatial-transcriptomic, patient multi-omic, CRISPR-screen, or proteome-wide PPS signature was found.

7. Anatomical structures affected

The primary organ is the eye, especially cornea (UBERON:0000964), anterior chamber (UBERON:0001836), iris (UBERON:0001769), and lens (UBERON:0001773). Disease can be bilateral; unilateral disease is more typical of milder isolated PA1 than classic PPS. (delas2025novelgeneticvariants pages 2-3)

Systemic sites include palate (UBERON:0001703), lip and craniofacial skeleton, appendicular skeleton and digits, brain (UBERON:0000955), ear/auditory apparatus, teeth and periodontium, heart (UBERON:0000948), vertebral column, and genitourinary tract. At tissue level, affected compartments include ocular neural-crest-derived mesenchyme, corneal endothelium/stroma, connective tissue, cartilage, bone, and craniofacial tissues. At subcellular level, the central compartment is the endoplasmic reticulum, followed downstream by the secretory pathway and extracellular matrix. (viga2018petersplussyndromeoral pages 2-4, delas2025novelgeneticvariants pages 2-3, vasudevan2015petersplussyndrome pages 1-3)

8. Temporal development

The molecular defect acts during embryogenesis. Eye, craniofacial, limb, and organ malformations are therefore congenital rather than acquired. Prenatal ultrasound may detect cleft lip/palate, short limbs, growth restriction, hydrocephalus, agenesis of the corpus callosum, or other severe malformations, but corneal/anterior-segment findings can be difficult to recognize prenatally.

The disorder is lifelong. There is no accepted staging system and no spontaneous remission. Structural lesions are usually stable, whereas complications—glaucoma, amblyopia, refractive error, developmental disability, feeding/speech difficulties, and dental disease—may emerge or worsen over time. Early infancy is a critical window for visual assessment and amblyopia prevention; infancy/childhood are also critical for feeding, cleft, hearing, cardiac, and developmental interventions. (viga2018petersplussyndromeoral pages 2-4, delas2025novelgeneticvariants pages 3-6)

9. Inheritance and population

Inheritance is autosomal recessive with high expected penetrance for biallelic loss-of-function genotypes, although expressivity is variable. Anticipation is not expected. Germline mosaicism has not been established as a major mechanism but cannot be categorically excluded in counseling after an apparently de novo event.

A robust PPS-specific prevalence or annual incidence was not identified. The 2.2–3.1 per 100,000 births figure reported in recent literature applies to the broader Peters anomaly spectrum, not PPS, and must not be relabeled as PPS prevalence. No validated sex bias, ethnic predilection, national hotspot, carrier frequency, or contemporary founder-effect estimate was found. (delas2025novelgeneticvariants pages 1-2)

10. Diagnostics

Clinical evaluation

A newborn with congenital central corneal opacity plus short limbs/brachydactyly, cleft lip/palate, dysmorphism, developmental or CNS anomalies, and/or heart disease should prompt PPS evaluation. Ophthalmologic examination—often under anesthesia—should define corneal opacity, anterior-chamber depth, iris/corneal/lens adhesions, cataract, axial length, refraction, optic nerve status, retina where visible, and intraocular pressure. Systemic workup should include growth and skeletal assessment, echocardiography, hearing testing, feeding/cleft evaluation, neurologic/developmental assessment, and renal/genitourinary imaging when indicated. (viga2018petersplussyndromeoral pages 2-4, delas2025novelgeneticvariants pages 3-6)

There is no routine blood chemistry, transferrin-isoelectric-focusing, urine-metabolite, biopsy, EEG, or imaging biomarker specific enough to confirm PPS. The loss of glucose on properdin TSRs is mechanistically informative but is not established as a broadly available clinical assay. (vasudevan2015petersplussyndrome pages 1-3)

Genetic testing strategy

  1. First-line: an anterior-segment dysgenesis/Peters anomaly panel including B3GLCT, or trio WES/WGS where systemic abnormalities make the differential broad.
  2. Ensure coverage of coding exons and canonical splice sites and assess copy-number variation.
  3. Confirm candidate variants and parental segregation by Sanger sequencing or equivalent validated methods.
  4. If one allele is found, consider deletion/duplication analysis, genome sequencing, and RNA studies for cryptic splice variants.
  5. CMA is useful when the phenotype is atypical or suggests a chromosomal Peters-plus-like condition; karyotype/FISH are not routine for classic PPS. Mitochondrial and repeat-expansion testing are not indicated unless another diagnosis is suspected.

In a 95-person Peters anomaly cohort, combined array, panel, exome, and genome approaches identified causes in approximately one third; B3GLCT was the most frequently implicated gene in syndromic PA, whereas two thirds remained without a molecular diagnosis. This is PA-spectrum diagnostic yield, not PPS test sensitivity. The abstract states: “Causative genetic defects involving 12 genes and CNVs were identified for 1/3 of patients.” Published February 2022; DOI: https://doi.org/10.1111/cge.14123. (chesneau2022firstevidenceof pages 14-17)

Differential diagnosis

Important alternatives include isolated PA1/PA2; Peters-plus-like syndrome; Axenfeld–Rieger spectrum; aniridia; congenital hereditary endothelial dystrophy; sclerocornea; congenital glaucoma; congenital infections causing corneal/cataract abnormalities; and syndromes involving PAX6, FOXC1, PITX2, PITX3, FOXE3, CYP1B1, SOX2, PXDN, COL4A1, CDH2, COL6A3, PEX2, or ZFHX4. PA1 tends to be milder, often unilateral, and less systemically involved; PA2 includes corneolenticular adhesion/cataract and is commonly bilateral. PPLS is reserved for a PPS-like clinical phenotype without diagnostic B3GLCT variants. (delas2025novelgeneticvariants pages 2-3, delas2025novelgeneticvariants pages 13-14, chesneau2022firstevidenceof pages 14-17)

11. Outcome and prognosis

No reliable five- or ten-year survival, mortality rate, or life-expectancy estimate exists. Prognosis depends chiefly on severity of bilateral eye disease, glaucoma, CNS malformations, congenital heart disease, airway/feeding problems, and developmental impairment. Vision can range from useful residual sight to light perception or blindness. In PA-spectrum follow-up, proposed keratoplasty or keratoprosthesis may be deferred because of glaucoma and retinal-detachment risks; one complex patient retained light perception with normal pressure at age 13, illustrating possible long-term survival but not a population prognosis. (delas2025novelgeneticvariants pages 3-6)

Potential complications include deprivation amblyopia, secondary glaucoma, retinal detachment following complex surgery, graft failure, refractive error, feeding and aspiration difficulties, recurrent otitis/conductive hearing loss, speech impairment, dental disease, seizures, and cardiac morbidity. Recovery of congenital structural abnormalities is not expected, but early visual, surgical, hearing, communication, and developmental interventions may improve function. No validated prognostic molecular biomarker or genotype-based outcome calculator is available.

12. Treatment and real-world implementation

There is no approved B3GLCT replacement, substrate therapy, chaperone, gene therapy, genome editing, RNA therapy, cell therapy, immunotherapy, or other targeted treatment.

Current management is multidisciplinary:

  • Eyes: immediate pediatric-ophthalmology assessment; refraction, occlusion/amblyopia therapy, low-vision support, and serial intraocular-pressure monitoring. Selected patients may undergo penetrating keratoplasty, lensectomy/cataract surgery, glaucoma procedures, or keratoprosthesis. Decisions are individualized because severe bilateral dysgenesis, glaucoma, graft failure, and retinal complications may limit benefit. Suggested NCIT concepts: Ophthalmic Examination (NCIT:C47891), supportive care, penetrating keratoplasty, cataract extraction, glaucoma surgery, and low-vision rehabilitation. (delas2025novelgeneticvariants pages 3-6)
  • Cleft/feeding: feeding support, nutritional monitoring, cleft-lip/palate repair, speech therapy, and ENT/audiology care.
  • Development: early-intervention services, physical therapy, occupational therapy, speech-language therapy, individualized education, and seizure management when needed.
  • Cardiac/hearing/renal: lesion-specific cardiology, hearing aids or other auditory rehabilitation, and urologic/nephrologic care.
  • Dental: preventive oral care is important because clefting, enamel/eruption abnormalities, cooperation limitations, cardiac disease, and anticonvulsant-associated gingival enlargement can complicate treatment. (viga2018petersplussyndromeoral pages 2-4)

No PPS-specific treatment-response rates, comparative surgical trials, pharmacogenomic recommendations, or registered interventional PPS clinical trials were found.

13. Prevention

Primary lifestyle prevention and immunization are not applicable. The principal preventive strategy is reproductive:

  • molecular confirmation of the familial B3GLCT variants;
  • carrier testing for adult relatives;
  • genetic counseling regarding 25% recurrence risk when both parents are carriers;
  • targeted prenatal diagnosis by chorionic-villus sampling or amniocentesis;
  • preimplantation genetic testing for monogenic disease;
  • prenatal ultrasound for structural anomalies, recognizing limited sensitivity for ocular findings.

Secondary/tertiary prevention includes early neonatal recognition, prompt visual-axis and amblyopia management, glaucoma surveillance, echocardiography, hearing assessment, feeding support, and developmental intervention. Population newborn screening is not available or justified for this ultra-rare structural disorder.

14. Other species and natural disease

B3GLCT and the POFUT2–TSR glycosylation pathway are evolutionarily conserved, but no naturally occurring veterinary disease established as an orthologous PPS syndrome was identified. PPS is not infectious and has no zoonotic or cross-species transmission. Ortholog records should be obtained from NCBI Gene/Alliance for each target species before assigning numeric gene identifiers.

15. Model organisms and experimental systems

The most persuasive PPS mechanism comes from human cell-biochemical systems and patient serum, including enzyme localization, glycosylation assays, secretion assays, and properdin glycoform analysis. These models directly test the molecular lesion but do not reproduce the full ocular, craniofacial, skeletal, or neurodevelopmental phenotype. (vasudevan2015petersplussyndrome pages 1-3)

Drosophila and other systems have been used to study conserved glycosyltransferases and TSR O-fucosylation, and mouse studies of individual TSR-containing proteins such as ADAMTS family members illuminate extracellular-matrix development. However, the retrieved evidence did not establish a validated B3glct-null mouse, zebrafish, organoid, or iPSC model that faithfully recapitulates human PPS. Consequently, claims about model-organism phenotype rescue or preclinical therapeutic efficacy would be premature.

Recent developments and expert interpretation

The 2022 study of 95 Peters anomaly patients demonstrated the practical value—and limitations—of combined CMA, panel, WES, and WGS, with a cause found in only one third and SOX2 newly implicated in PA. This supports broad genomic testing when a patient has an atypical or B3GLCT-negative PPS-like presentation. (chesneau2022firstevidenceof pages 14-17)

A 2023 systematic review of inherited carbohydrate-metabolism disorders included B3GLCT/B3GALTL-related PPS among glycosylation disorders with reported cardiac defects, reinforcing the need for cardiovascular screening but not establishing a new PPS-specific therapy. The main 2024 developments retrieved concerned neurocristopathy frameworks and childhood-glaucoma registry development rather than PPS-specific trials. The field’s principal unmet needs remain a longitudinal natural-history registry, standardized phenotype frequencies, patient-reported outcomes, validated disease models, a clinical glycosylation biomarker, and therapeutic strategies restoring TSR glycosylation or secretion.

The following table provides consolidated ontology and database-loading suggestions. Terms explicitly marked “requiring validation” should be checked against current ontology releases before ingestion.

Domain Finding Suggested ontology identifiers/terms Evidence/notes
Disease identity Peters plus syndrome is a rare syndromic Peters anomaly / congenital disorder of glycosylation caused by biallelic B3GLCT variants MONDO:0009856; suggested term: autosomal recessive congenital disorder of glycosylation; suggested term: syndromic anterior segment dysgenesis Open Targets links Peters plus syndrome specifically to B3GLCT; literature distinguishes PPS from isolated Peters anomaly and Peters-plus-like syndrome (OpenTargets Search: Peters plus syndrome, totonzuranska2019contributionofa pages 1-3, delas2025novelgeneticvariants pages 2-3)
Synonyms / nomenclature Historical/alternative gene name overlap may appear in records suggested terms requiring validation: Peters'-plus syndrome; Peters plus; B3GALTL-related Peters plus syndrome; B3GLCT-related Peters plus syndrome Sources note former gene symbol B3GALTL and current B3GLCT; curation should normalize both (totonzuranska2019contributionofa pages 1-3, vasudevan2015petersplussyndrome pages 1-3)
Etiology Primary cause is germline biallelic loss of function in B3GLCT suggested term: germline autosomal recessive inheritance; HGNC gene symbol: B3GLCT Human genetic evidence is strong and disease-level, not EHR-derived; recurrent splice and truncating variants reported (OpenTargets Search: Peters plus syndrome, totonzuranska2019contributionofa pages 1-3, delas2025novelgeneticvariants pages 14-15)
Key variant class Recurrent canonical splice variant and other truncating alleles are important pathogenic classes suggested variant terms: c.660+1G>A (rs80338851); c.755delC (p.Thr252fs) requiring nomenclature validation c.660+1G>A is repeatedly cited as previously known PPS allele; 2019 report adds novel frameshift c.755delC (totonzuranska2019contributionofa pages 1-3)
Core ocular phenotype Peters anomaly / anterior segment dysgenesis with congenital corneal opacity HP:0000659 Corneal opacity; suggested HPO term requiring validation: Peters anomaly; suggested HPO term: Anterior segment dysgenesis Core defining feature of PPS; congenital onset (totonzuranska2019contributionofa pages 1-3, delas2025novelgeneticvariants pages 2-3)
Ocular adhesion phenotype Iridocorneal and/or lenticulocorneal adhesions may accompany corneal opacity suggested HPO terms requiring ontology validation: iridocorneal adhesions; corneolenticular adhesions Well-described within Peters anomaly spectrum; use as phenotype mapping after validation (delas2025novelgeneticvariants pages 2-3, chesneau2022firstevidenceof pages 14-17)
Ocular lens phenotype Congenital cataract can occur within Peters anomaly spectrum and PPS differential workup HP:0000519 Cataract Cataract is especially relevant in PA2 and syndromic differential diagnosis; not every PPS case has cataract (delas2025novelgeneticvariants pages 2-3, ahmad2022geneticsofcongenital pages 1-6)
Ocular complication Secondary glaucoma is a major vision-threatening complication HP:0000501 Glaucoma PA-spectrum review cited glaucoma in 30-70% of PA patients; this should not be over-interpreted as PPS-specific frequency (delas2025novelgeneticvariants pages 2-3)
Craniofacial phenotype Cleft lip with/without cleft palate and characteristic facial dysmorphism HP:0000204 Cleft upper lip; HP:0000175 Cleft palate Clinical diagnosis commonly includes cleft lip/palate and facial changes (viga2018petersplussyndromeoral pages 2-4, vasudevan2015petersplussyndrome pages 1-3)
Growth / skeletal phenotype Short stature, short limbs, brachydactyly are characteristic systemic findings HP:0004322 Short stature; HP:0001156 Brachydactyly; suggested HPO term: rhizomelia/short limbs requiring validation PPS is distinguished from isolated PA by systemic skeletal/growth findings (viga2018petersplussyndromeoral pages 2-4, delas2025novelgeneticvariants pages 2-3, vasudevan2015petersplussyndrome pages 1-3)
Neurodevelopmental phenotype Developmental delay / intellectual disability of variable severity HP:0001263 Global developmental delay; HP:0001249 Intellectual disability Often described as variable psychomotor delay/mental retardation in older literature; harmonize to current HPO usage (viga2018petersplussyndromeoral pages 2-4)
Auditory phenotype Hearing loss can occur, sometimes linked to congenital ear malformations HP:0000365 Hearing impairment Conductive hearing loss noted in syndrome descriptions and case reports (viga2018petersplussyndromeoral pages 2-4)
Cardiac phenotype Congenital heart defects are variably reported HP:0001627 Abnormality of the cardiovascular system morphology; suggested HPO term: congenital heart defect requiring validation One review-oriented source states cardiac malformations in ~33% of reported cases, but this estimate derives from small literature and should be treated cautiously (viga2018petersplussyndromeoral pages 2-4)
Additional organ involvement Brain/CNS, urogenital, and other multisystem anomalies may occur in severe cases suggested HPO terms requiring validation: hydrocephalus; agenesis of corpus callosum; urogenital abnormality Prenatal and case literature suggest broader malformation spectrum; evidence is case-based and variable (delas2025novelgeneticvariants pages 14-15)
Molecular mechanism B3GLCT is an ER-localized beta-1,3-glucosyltransferase that adds glucose to O-fucosylated TSRs, producing Glcβ1-3Fuc GO:0005783 endoplasmic reticulum; suggested GO term: protein O-linked glycosylation; suggested GO term: O-fucose glycan extension on thrombospondin type-1 repeat Vasudevan et al. provide direct mechanistic evidence for ER localization and TSR disaccharide formation (vasudevan2015petersplussyndrome pages 1-3)
Upstream partner POFUT2 adds the initial O-fucose to properly folded TSRs upstream of B3GLCT suggested term requiring validation: POFUT2-mediated protein O-fucosylation of TSR domains PPS mechanism is part of a two-step POFUT2→B3GLCT pathway (vasudevan2015petersplussyndrome pages 1-3)
Protein homeostasis mechanism PPS mutations disrupt a noncanonical ER quality-control system for properly folded TSR-containing proteins GO:0006457 protein folding; suggested GO term: endoplasmic reticulum protein quality control; suggested GO term: regulation of protein secretion Mechanistic hallmark from Current Biology 2015; downstream effect is impaired folding/ER exit/secretion for susceptible TSR proteins (totonzuranska2019contributionofa pages 1-3, vasudevan2015petersplussyndrome pages 1-3)
Candidate affected protein classes TSR-containing extracellular proteins are likely downstream effectors suggested terms requiring validation: thrombospondin-1; thrombospondin-2; ADAMTS family; ADAMTSL family; properdin Human/cell biochemical evidence supports defective glycosylation of TSR-bearing proteins; exact causal contributors to each PPS feature remain incompletely mapped (vasudevan2015petersplussyndrome pages 1-3)
Cell types Relevant developmental cell populations likely include corneal endothelium, neural crest derivatives, and chondrocytes CL:0000114 endothelial cell; suggested CL term: corneal endothelial cell; CL:0000000 cell? / suggested CL term: neural crest cell; CL:0000138 chondrocyte Numeric CL IDs should be validated before loading except for generic chondrocyte/endothelial mappings; literature supports neural crest and connective/skeletal involvement conceptually (delas2025novelgeneticvariants pages 2-3)
Anatomical structures Primary affected sites include cornea, anterior chamber, iris, lens, palate, limb skeleton, brain, and heart UBERON:0000964 cornea; UBERON:0001769 iris; UBERON:0001773 lens; UBERON:0001836 anterior chamber of eyeball; UBERON:0001703 palate; UBERON:0000922 embryo? / suggested term: limb skeleton; UBERON:0000955 brain; UBERON:0000948 heart Use validated UBERON mappings for local database ingestion; eye and multisystem anatomy are well supported clinically (viga2018petersplussyndromeoral pages 2-4, delas2025novelgeneticvariants pages 2-3, vasudevan2015petersplussyndrome pages 1-3)
Inheritance / population Inheritance is autosomal recessive; robust PPS-specific prevalence/incidence not found suggested term: autosomal recessive inheritance Do not substitute Peters anomaly prevalence (2.2-3.1 per 100,000 births) for PPS prevalence; PPS remains ultra-rare (totonzuranska2019contributionofa pages 1-3, delas2025novelgeneticvariants pages 1-2)
Diagnostics Diagnostic workflow combines ophthalmic exam with molecular confirmation of biallelic B3GLCT variants NCIT:C47891 Ophthalmic Examination; NCIT:C84351 Whole Exome Sequencing; suggested NCIT term: gene panel testing; suggested NCIT term: Sanger sequencing confirmation WES/WGS/panel testing are standard modern approaches in PA-spectrum diagnosis; PPS confirmation is genotype-driven (totonzuranska2019contributionofa pages 1-3, delas2025novelgeneticvariants pages 2-3, chesneau2022firstevidenceof pages 14-17)
Differential diagnosis Distinguish from isolated Peters anomaly and Peters-plus-like syndrome; other PA genes are relevant suggested disease/gene terms: PAX6, PITX2, PITX3, FOXE3, FOXC1, CYP1B1, SOX2, PXDN, COL4A1, CDH2, PEX2, ZFHX4 PPLS denotes PPS-like phenotype without B3GLCT variants; isolated/syndromic PA is genetically heterogeneous (delas2025novelgeneticvariants pages 2-3, delas2025novelgeneticvariants pages 13-14, chesneau2022firstevidenceof pages 14-17)
Treatment / management Care is supportive and multidisciplinary; ocular monitoring, amblyopia prevention, glaucoma surveillance, selective surgery, cleft and hearing management NCIT:C157740 Supportive Care; suggested NCIT terms: penetrating keratoplasty; Boston keratoprosthesis implantation; cleft palate repair; hearing aid therapy; physical therapy; dental care No disease-modifying therapy found; management is phenotype-directed and risk-benefit sensitive (viga2018petersplussyndromeoral pages 2-4, delas2025novelgeneticvariants pages 3-6)
Prevention Main preventive options are genetic counseling, reproductive testing, and prenatal/preimplantation diagnosis in at-risk families NCIT:C15240 Genetic Counseling; suggested NCIT terms: prenatal molecular diagnosis; carrier screening; preimplantation genetic testing Prevention is familial/reproductive rather than environmental; parental exome sequencing has been used to establish recurrence risk in lethal/prenatal AR disease settings including B3GLCT diagnoses (viga2018petersplussyndromeoral pages 2-4, delas2025novelgeneticvariants pages 14-15)
Research / recent developments Recent work mainly refines PA-spectrum genetics rather than PPS-specific therapy suggested terms: comprehensive genomic analysis; rare disease registry; molecular diagnosis 2022-2024 literature highlights expanded PA genes, WES/WGS use, and childhood glaucoma registry context; no PPS interventional trials identified (delas2025novelgeneticvariants pages 3-6, chesneau2022firstevidenceof pages 14-17)
Evidence gaps No validated environmental or infectious cause, protective factor, biomarker panel, targeted therapy, pharmacogenomic rule, omics diagnostic signature, or natural animal disease established suggested terms: evidence gap; no data Also no robust PPS-specific survival statistics, QoL instruments, or confirmed whole-animal PPS model were found in retrieved evidence; clinical trial search found no relevant interventional PPS trial (vasudevan2015petersplussyndrome pages 1-3, ahmad2022geneticsofcongenital pages 1-6, delas2025novelgeneticvariants pages 13-14)

Table: This table summarizes database-ready disease findings, ontology mappings, and evidence notes for Peters plus syndrome. It emphasizes confirmed identifiers and mechanisms while flagging terms and evidence gaps that require ontology or literature validation.

Evidence limitations

PPS literature consists mainly of small series, case reports, and one strong mechanistic program; therefore, many apparent frequencies are vulnerable to ascertainment and publication bias. The PA-spectrum prevalence and glaucoma statistics cannot be treated as molecularly confirmed PPS statistics. No robust data were found for PPS-specific incidence, carrier frequency, sex ratio, survival, formal quality of life, penetrance stratified by variant, environmental interactions, protective alleles, multi-omics signatures, natural animal disease, or treatment efficacy. Direct quotations are limited to text available from retrieved abstracts; quotations should not be inferred from secondary summaries.

References

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