Aortic Valve Disease 3

Mendelian MONDO:0032783 Pathograph 18 Show in embeddings browser

Aortic valve disease 3 is an autosomal dominant, incompletely penetrant ROBO4-associated valvulo-aortopathy in which bicuspid aortic valve, aortic valve stenosis, and aneurysm of the aortic root and/or ascending aorta occur alone or in combination, with atrial septal defect in one reported family. The proposed mechanism is endothelial: loss of ROBO4 function in cultured aortic endothelial cells weakens the endothelial barrier and shifts the cells toward a mesenchymal, invasive state, and aneurysm tissue from an affected individual shows plasma albumin penetrating the intima with fibroproliferative remodeling and elastic-fiber fragmentation of the superficial media. The disease rests on two segregating families, a rare-variant enrichment in a BAV/ascending-aneurysm cohort, and mouse and zebrafish models; ClinGen classifies the gene-disease relationship as Moderate.

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1
Mappings
1
Inheritance
5
Pathophys.
5
Phenotypes
18
Pathograph
1
Genes
2
Variants
2
Medical Actions
4
Models
1
Deep Research
🔗

Mappings

MONDO
MONDO:0032783 aortic valve disease 3
skos:exactMatch MONDO
Primary MONDO disease identifier for the ROBO4-defined aortic valve disease.
👪

Inheritance

1
Autosomal dominant HP:0000006
Heterozygous ROBO4 variants segregated with disease in two families. In the larger family two clinically unaffected female relatives carried the splice variant, and carriers showed BAV with ascending aneurysm, isolated BAV, or isolated aortic aneurysm. Seven of the eight affected members of that family were male. No numerical penetrance estimate exists.
Autosomal dominant inheritance Penetrance: INCOMPLETE Expressivity: VARIABLE
Show evidence (4 references)
PMID:30455415 SUPPORT Human Clinical
"Here, we report the identification of variants in ROBO4 (which encodes a factor known to contribute to endothelial performance) that segregate with disease in two families."
Segregation of heterozygous ROBO4 variants with disease in two families is the basis for the dominant inheritance pattern.
PMID:30455415 SUPPORT Human Clinical
"Two clinically unaffected female family members were heterozygous for the ROBO4 splice-site mutation."
Unaffected heterozygous carriers in family 1 establish incomplete penetrance.
PMID:30455415 SUPPORT Human Clinical
"a concept further supported by the presence of either BAV/AscAA, isolated BAV, or isolated AscAA in family members segregating the same ROBO4 mutation"
Different manifestations among carriers of one variant establish variable expressivity.
+ 1 more reference
⚙

Pathophysiology

5
ROBO4 Loss of Function
Heterozygous germline ROBO4 variants reduce or structurally disrupt the endothelial ROBO4 receptor. The family 1 splice-donor variant causes in-frame skipping of exon 13, removing 36 amino acids from the intracellular domain; the family 2 missense variant p.Arg64Cys changes a conserved residue in the first extracellular Ig-like domain. Silencing and mutant-expression experiments point to loss of function, by haploinsufficiency or an antimorphic effect of mutant protein, as the pathogenic mechanism.
ROBO4 hgnc:17985 ↓ DECREASED HUGO Gene Nomenclature Committee (hgnc) Relation: this pathophysiological event involves this gene This pathophysiological event involves decreased ROBO4 (hgnc:17985). hgnc:17985 is a gene from the HUGO Gene Nomenclature Committee.
ROBO4 endothelial receptor activity GO:0038023 Gene Ontology (GO) Relation: this pathophysiological event involves this molecular function This pathophysiological event involves ROBO4 endothelial receptor activity, annotated with signaling receptor activity (GO:0038023). GO:0038023 is a molecular function from the Gene Ontology.
Animal models
Robo4 exon 13 splice knock-in mouse (Robo4Skip13) Mouse recapitulates
Downstream
Impaired Endothelial Barrier Function ROBO4 silencing, or expression of either familial variant, made cultured human aortic endothelial monolayers more permeable.
Mesenchymal Shift of Aortic Endothelial Cells The same perturbations induced mesenchymal markers, cell elongation and invasion. The paper reports this in parallel with the barrier defect and does not show that one causes the other.
Abnormal Aortic Valve Development Loss of Robo4 in mice produces aortic valve thickening, bicuspid valves and valve dysfunction. The intervening developmental steps were not studied; ROBO4 is expressed in the endocardial cushions where the valve forms.
Show evidence (4 references)
PMID:18345009 SUPPORT INDIRECT In Vitro
"Activation of Robo4 by Slit2 inhibits vascular endothelial growth factor (VEGF)-165-induced migration, tube formation and permeability in vitro"
Establishes ROBO4 as an endothelial receptor whose activation suppresses VEGF-induced permeability, which supports the molecular function bound on this node. It is not a study of the disease variants.
PMID:30455415 SUPPORT In Vitro
"Amplification and sequencing of cDNA derived from patient and control fibroblasts showed that the splice-site mutation results in the skipping of the 108 base pairs encoding exon 13 of ROBO4, resulting in an in-frame transcript encoding a protein isoform missing 36 amino acids from the..."
Cultured patient fibroblasts show the molecular consequence of the family 1 splice variant.
PMID:30455415 SUPPORT In Vitro
"These data suggest that loss-of-function (by functional haploinsufficiency or the antimorphic effects of overexpressed mutant protein) is the relevant pathogenic mechanism."
The authors' conclusion from the cultured endothelial-cell experiments that the variants act through loss of function.
+ 1 more reference
Impaired Endothelial Barrier Function
ROBO4-deficient aortic endothelium loses barrier function, with reduced expression of the tight-junction protein TJP1 and the adherens-junction protein VE-cadherin. In aneurysm tissue from an affected family member, endothelial ROBO4 staining was diminished and plasma albumin penetrated the aortic intima, whereas it stayed at the endothelial surface in control aorta.
aortic endothelial cell CL:0002544 Cell Ontology (CL) Relation: this pathophysiological event involves this cell type This pathophysiological event involves aortic endothelial cell (CL:0002544). CL:0002544 is a cell type from the Cell Ontology.
establishment of endothelial barrier GO:0061028 ↓ DECREASED Gene Ontology (GO) Relation: this pathophysiological event involves this biological process This pathophysiological event involves decreased establishment of endothelial barrier (GO:0061028). GO:0061028 is a biological process from the Gene Ontology.
ascending aorta UBERON:0001496 Uberon multi-species anatomy ontology (UBERON) Relation: this pathophysiological event occurs in this anatomical location This pathophysiological event occurs in ascending aorta (UBERON:0001496). UBERON:0001496 is an anatomical location from the Uberon multi-species anatomy ontology.
Experimental models
ROBO4-silenced or mutant-expressing human aortic endothelial cells PRIMARY CELL CULTURE
Downstream
Aortic Wall Medial Remodeling The authors infer from the patient tissue that barrier failure contributes to remodeling of the aortic media; the order of events was not tested.
Show evidence (3 references)
PMID:30455415 SUPPORT In Vitro
"Loss of barrier function associated with down regulation of expression of TJP1 and VE-cadherin mRNA and protein, indicative of loss of tight- and adherens-junction integrity, respectively"
Junctional protein loss accompanies the barrier defect in cultured human aortic endothelial cells.
PMID:30455415 SUPPORT Human Clinical
"immunostaining for albumin was restricted to the endothelial surface in control aorta, but substantial penetration into the aortic intima was observed in patient tissue"
Resected aneurysm tissue from one affected individual shows increased permeability in vivo. This is a single patient compared with a single control.
PMID:30455415 SUPPORT Human Clinical
"ROBO4 was strongly expressed in endothelial cells in control aorta as evidenced by co-localization with platelet endothelial cell adhesion molecule 1 (CD31) but was diminished in the endothelium in the BAV/AscAA sample"
Reduced endothelial ROBO4 in the patient's aneurysmal aorta.
Mesenchymal Shift of Aortic Endothelial Cells
ROBO4-deficient aortic endothelial cells express alpha-smooth muscle actin and SNAI1, elongate and invade collagen gels, a pattern the authors read as suggestive of endothelial-to-mesenchymal transition. In the patient's aneurysm, ROBO4-positive cells co-staining for alpha-smooth muscle actin were found in the aortic media. No single signaling pathway was identified: ROBO4 silencing gave a modest decline in BMP and Notch target-gene expression without altered TGF-beta responses.
aortic endothelial cell CL:0002544 Cell Ontology (CL) Relation: this pathophysiological event involves this cell type This pathophysiological event involves aortic endothelial cell (CL:0002544). CL:0002544 is a cell type from the Cell Ontology.
Experimental models
ROBO4-silenced or mutant-expressing human aortic endothelial cells PRIMARY CELL CULTURE
Downstream
Aortic Wall Medial Remodeling Proposed by the authors as a contributor alongside barrier failure; not tested experimentally.
Show evidence (3 references)
PMID:30455415 SUPPORT In Vitro
"Together, these results suggest that reduction or structural disruption of ROBO4 compromises endothelial identity and performance, as well as its capacity to suppress transition to a mesenchymal invasive character and synthetic repertoire."
The authors' synthesis of the cultured-cell results.
PMID:30455415 SUPPORT Human Clinical
"the aneurysm tissue uniquely showed infiltration of ROBO4+ cells into the aortic media with co-staining for α-SMA"
A tissue observation in one patient consistent with mesenchymal behavior of ROBO4-expressing cells in vivo.
PMID:30455415 SUPPORT In Vitro
"Assessment of expression of prototypical target genes suggested a modest decline in bone morphogenetic protein (BMP) and Notch activity without altered TGFβ responses upon ROBO4 silencing."
Records that no single downstream pathway was shown to drive the mesenchymal shift.
Aortic Wall Medial Remodeling
Aneurysmal ascending aorta from an affected family member showed a fibroproliferative response with collagen accumulation in the intima and superficial media, and decreased elastin with fragmented, disarrayed elastic fibers in the superficial media.
ascending aorta UBERON:0001496 Uberon multi-species anatomy ontology (UBERON) Relation: this pathophysiological event occurs in this anatomical location This pathophysiological event occurs in ascending aorta (UBERON:0001496). UBERON:0001496 is an anatomical location from the Uberon multi-species anatomy ontology.
Downstream
Aortic root aneurysm Medial remodeling was observed in aneurysmal tissue; that it produces the dilatation is inferred, not demonstrated for this disease.
Ascending tubular aorta aneurysm Medial remodeling was observed in aneurysmal tissue; that it produces the dilatation is inferred, not demonstrated for this disease.
Show evidence (2 references)
PMID:30455415 SUPPORT Human Clinical
"Histologic analyses showed a strong fibroproliferative response in the intima and superficial medial layer of patient aorta, as evidenced by increased cellularity and the accumulation of collagen upon Masson's trichrome staining."
Fibroproliferative remodeling in one patient's aneurysm tissue.
PMID:30455415 SUPPORT Human Clinical
"decreased elastin content and fragmentation and disarray of elastic fibers in the superficial media was revealed upon Verhoeff-Van Gieson (VVG) staining"
Elastic-fiber loss in the same patient's aneurysm tissue.
Abnormal Aortic Valve Development
ROBO4 is expressed in the endocardium of the developing outflow-tract cushions and later in endothelial and interstitial cells of the developing aortic valve. Robo4-deficient mice develop valve thickening, bicuspid and occasionally quadricuspid valves, and valve stenosis or regurgitation. Valve pathology from an affected family member with BAV showed valve thickening with a fibroproliferative process.
endocardial cell CL:0002350 Cell Ontology (CL) Relation: this pathophysiological event involves this cell type This pathophysiological event involves endocardial cell (CL:0002350). CL:0002350 is a cell type from the Cell Ontology.
aortic valve morphogenesis GO:0003180 ⚠ ABNORMAL Gene Ontology (GO) Relation: this pathophysiological event involves this biological process This pathophysiological event involves abnormal aortic valve morphogenesis (GO:0003180). GO:0003180 is a biological process from the Gene Ontology.
aortic valve UBERON:0002137 Uberon multi-species anatomy ontology (UBERON) Relation: this pathophysiological event occurs in this anatomical location This pathophysiological event occurs in aortic valve (UBERON:0002137). UBERON:0002137 is an anatomical location from the Uberon multi-species anatomy ontology.
Animal models
Robo4 knockout mouse (Robo4tm1Lex) Mouse partially recapitulates
Robo4 exon 13 splice knock-in mouse (Robo4Skip13) Mouse partially recapitulates
robo4 frameshift zebrafish (robo4 delta7) Zebrafish partially recapitulates
Downstream
Bicuspid aortic valve Abnormal valve formation yields a bicuspid valve in some carriers.
Aortic valve stenosis Thickened, malformed valves become stenotic. Mouse evidence; in family 2 a carrier had stenosis requiring surgery.
Show evidence (2 references)
PMID:30455415 SUPPORT Model Organism
"We observed that mouse ROBO4 was expressed in the endocardial layer of the cushions and delamination zones at embryonic day 11.5"
Places ROBO4 in the cells that form the valve primordia.
PMID:30455415 SUPPORT Human Clinical
"Pathology from one family member with BAV revealed valve thickening in association with a pronounced fibroproliferative process"
Valve pathology in one affected carrier.
⬡

Pathograph

Use the checkboxes to hide or show graph categories. Hover nodes for evidence and cross-linked metadata.
Pathograph: causal mechanism network for Aortic Valve Disease 3 Interactive directed graph showing how pathophysiology mechanisms, phenotypes, genetic factors and variants, experimental models, environmental triggers, and treatments relate through causal and linked edges.
●

Phenotypes

5
Aortic root aneurysm Cardiovascular HP:0002616 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Aortic root aneurysm (HP:0002616). HP:0002616 is a phenotype from the Human Phenotype Ontology.
Show evidence (2 references)
PMID:30455415 SUPPORT Human Clinical
"In one large family (Family 1), eight individuals showed AoRA with or without DAscAA; two had associated BAV"
Aortic root aneurysm in all affected members of family 1.
CGGV:assertion_3531e2eb-71cd-446c-8956-acb15c3adc7b-2025-01-24T170000.000Z SUPPORT Other
"It is associated with aortic root aneurysm, ascending aortic aneurysm, and atrial septal defect (ASD) in some individuals."
ClinGen's disease description lists aortic root aneurysm.
Ascending tubular aorta aneurysm Cardiovascular HP:0004970 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Ascending aortic aneurysm, annotated with Ascending tubular aorta aneurysm (HP:0004970). HP:0004970 is a phenotype from the Human Phenotype Ontology.
Show evidence (2 references)
PMID:30455415 SUPPORT Human Clinical
"In one large family (Family 1), eight individuals showed AoRA with or without DAscAA; two had associated BAV"
Distal ascending aneurysm (DAscAA) in part of family 1.
CGGV:assertion_3531e2eb-71cd-446c-8956-acb15c3adc7b-2025-01-24T170000.000Z SUPPORT Other
"It is associated with aortic root aneurysm, ascending aortic aneurysm, and atrial septal defect (ASD) in some individuals."
ClinGen's disease description lists ascending aortic aneurysm.
Bicuspid aortic valve Cardiovascular HP:0001647 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Bicuspid aortic valve (HP:0001647). HP:0001647 is a phenotype from the Human Phenotype Ontology.
Show evidence (2 references)
PMID:30455415 SUPPORT Human Clinical
"In family 2, WES revealed a heterozygous ROBO4 missense variant (c.190C>T; p.Arg64Cys) in a woman, with atrial septal defect (ASD) and aortic valve stenosis (AVS) that required surgery, and her son with ASD, BAV and significant AVS"
BAV in the family 2 son.
PMID:30455415 SUPPORT Human Clinical
"In one large family (Family 1), eight individuals showed AoRA with or without DAscAA; two had associated BAV"
BAV in two members of family 1.
Aortic valve stenosis Cardiovascular HP:0001650 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Aortic valve stenosis (HP:0001650). HP:0001650 is a phenotype from the Human Phenotype Ontology.
Show evidence (2 references)
PMID:30455415 SUPPORT Human Clinical
"In family 2, WES revealed a heterozygous ROBO4 missense variant (c.190C>T; p.Arg64Cys) in a woman, with atrial septal defect (ASD) and aortic valve stenosis (AVS) that required surgery, and her son with ASD, BAV and significant AVS"
Aortic valve stenosis in both family 2 carriers.
CGGV:assertion_3531e2eb-71cd-446c-8956-acb15c3adc7b-2025-01-24T170000.000Z SUPPORT Other
"AOVD is characterized by aortic stenosis and/or bicuspid aortic valve (BAV)."
ClinGen's disease definition.
Atrial septal defect Cardiovascular HP:0001631 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Atrial septal defect (HP:0001631). HP:0001631 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:30455415 SUPPORT Human Clinical
"In family 2, WES revealed a heterozygous ROBO4 missense variant (c.190C>T; p.Arg64Cys) in a woman, with atrial septal defect (ASD) and aortic valve stenosis (AVS) that required surgery, and her son with ASD, BAV and significant AVS"
ASD in both family 2 carriers.
🧬

Genetic Associations

1
ROBO4 (Defining gene; ClinGen Moderate for autosomal dominant AOVD3)
Gene: ROBO4 hgnc:17985 HUGO Gene Nomenclature Committee (hgnc) Relation: this disease-associated gene is this gene This disease-associated gene is ROBO4 (hgnc:17985). hgnc:17985 is a gene from the HUGO Gene Nomenclature Committee. variant_origin: GERMLINE
Show evidence (3 references)
PMID:30455415 SUPPORT Human Clinical
"Collectively, among familial and individual probands (WES and targeted sequencing), 13/736 (1.77%) had a ROBO4 variant that passed a priori filtering constraints while one rare (absent from ExAC) missense mutation was observed among 376 rigorously phenotyped controls"
Rare-variant enrichment in BAV/ascending-aneurysm probands.
PMID:32748548 REFUTE Human Clinical
"Rare variants of NOTCH1, ROBO4, SMAD6, or GATA4 do not significantly contribute to BAV in cohorts with HTAD."
A burden analysis found no significant ROBO4 contribution to BAV in a heritable thoracic aortic disease cohort. This bears on how much of BAV with aortic disease ROBO4 explains, not on segregation in the original families.
PMID:32748548 SUPPORT Human Clinical
"Rare NOTCH1 and ROBO4 variants were also enriched in the EBAV cohort, but this was not statistically significant due to limited power in this small data set."
A non-significant trend toward ROBO4 enrichment in early-onset BAV complications (63 probands).
Variants (2)
ROBO4 c.2056+1G>T
Splice-donor variant (NM_019055.5) segregating in family 1, carried by all eight affected members and two unaffected women; causes in-frame skipping of exon 13.
Show evidence (1 reference)
PMID:30455415 SUPPORT Human Clinical
"We confirmed that all eight affected family members carried the mutation."
Segregation of the splice variant with disease in family 1.
ROBO4 c.190C>T (p.Arg64Cys)
Missense variant in the first Ig-like extracellular domain, found in an affected mother and son (family 2) and in one further unrelated proband.
Show evidence (1 reference)
PMID:30455415 SUPPORT Human Clinical
"The missense mutations observed in the targeted sequencing cohort include an independent example of the p.Arg64Cys variant observed in Family 2."
Recurrence of p.Arg64Cys in an unrelated proband.
💊

Medical Actions

2
Aortic Valve Replacement
Action: aortic valve replacementNCI Thesaurus (NCIT) Relation: this treatment is this clinical intervention This treatment is aortic valve replacement (NCIT:C50815). NCIT:C50815 is a clinical intervention from the NCI Thesaurus. Ontology label: Aortic Valve Replacement NCIT:C50815
Platform: Surgery
Surgical replacement for severe aortic valve stenosis; the affected mother in family 2 required valve surgery. This treats the lesion, not the inherited susceptibility.
Mechanism Target:
Aortic valve stenosis
Show evidence (1 reference)
PMID:30455415 SUPPORT Human Clinical
"In family 2, WES revealed a heterozygous ROBO4 missense variant (c.190C>T; p.Arg64Cys) in a woman, with atrial septal defect (ASD) and aortic valve stenosis (AVS) that required surgery"
Valve surgery in a ROBO4 carrier with stenosis.
Prophylactic Aortic Root and Ascending Aorta Replacement
Action: aortic root and ascending aorta replacement surgeryNCI Thesaurus (NCIT) Relation: this treatment is this clinical intervention This treatment is aortic root and ascending aorta replacement surgery, annotated with Surgical Procedure (NCIT:C15329). NCIT:C15329 is a clinical intervention from the NCI Thesaurus. Ontology label: Surgical Procedure NCIT:C15329
Platform: Surgery
Surgical replacement of the dilated aortic root and/or ascending aorta at guideline diameter thresholds for BAV-associated aortopathy. Thresholds are general BAV guidance and have not been validated for ROBO4 carriers.
Mechanism Target:
Aortic root aneurysm
Ascending tubular aorta aneurysm
Show evidence (1 reference)
PMID:36322642 SUPPORT REVIEW SYNTHESIS Other
"In patients with a BAV and a diameter of the aortic root, ascending aorta, or both of ≥5.5 cm, surgery to replace the aortic root, ascending aorta, or both is recommended."
Guideline surgical threshold for BAV-associated aortopathy.
🔬

Diagnosis

3
Transthoracic Echocardiography
Echocardiography defines valve morphology and function and measures the aortic root and ascending aorta. This is general BAV guidance, not ROBO4-specific.
echocardiography NCIT:C16525 NCI Thesaurus (NCIT)
Show evidence (1 reference)
PMID:36322642 SUPPORT REVIEW SYNTHESIS Other
"In patients with a BAV, TTE is indicated to evaluate valve morphology and function, to evaluate the diameter of the aortic root and ascending aorta, and to evaluate for aortic coarctation and other associated cardiovascular defects."
Guideline recommendation for BAV generally.
Echocardiographic Screening of First-Degree Relatives
Because penetrance is incomplete and carriers may have isolated valve or aortic disease, relatives are screened by imaging. The guideline recommendation applies to BAV with aortic dilatation generally.
echocardiography NCIT:C16525 NCI Thesaurus (NCIT)
Show evidence (1 reference)
PMID:36322642 SUPPORT REVIEW SYNTHESIS Other
"In patients with a BAV and a dilated aortic root or ascending aorta, screening of all first-degree relatives by TTE is recommended to evaluate for the presence of a BAV, dilation of the aortic root and ascending aorta, or both"
Guideline basis for family imaging.
Multigene Panel Testing
ROBO4 is listed among genes for BAV with thoracic aortic aneurysm in the 2022 ACC/AHA aortic guideline's gene table.
Show evidence (1 reference)
PMID:36322642 SUPPORT REVIEW SYNTHESIS Other
"BAV with TAA | TGFBR2, MAT2A, GATA5, SMAD6, LOX, ROBO4, TBX20"
The guideline gene table names ROBO4 for BAV with thoracic aortic aneurysm.
🧫

Experimental Models

1
ROBO4-silenced or mutant-expressing human aortic endothelial cells PRIMARY_CELL_CULTURE
Cells were treated with ROBO4 siRNA or transiently transfected with wild-type, exon 13-deleted or p.Arg64Cys ROBO4 constructs, then assayed for dextran permeability, junctional markers, mesenchymal markers, shape and invasion.
aortic endothelial cell CL:0002544 Cell Ontology (CL) Relation: this experimental model uses this cell type This experimental model uses aortic endothelial cell (CL:0002544). CL:0002544 is a cell type from the Cell Ontology.
Organism
Homo sapiens NCBITaxon:9606 NCBI Taxonomy (NCBITaxon) Relation: this experimental model is built in this organism This experimental model is built in Homo sapiens (NCBITaxon:9606). NCBITaxon:9606 is an organism from the NCBI Taxonomy.
Cell source
Commercial primary human aortic endothelial cells, passages 2-6
Culture
Monolayers on porous inserts and cell aggregates on collagen gels
Publication
PMID:30455415
Pathograph links
Impaired Endothelial Barrier Function perturbs fidelity: moderate observes: cellular
Limitations: Transient overexpression in static culture, without flow, valve tissue context or lifetime exposure.
Show evidence (1 reference)
PMID:30455415 SUPPORT In Vitro
"Either ROBO4 silencing or expression of ROBO4 variants resulted in loss of endothelial barrier function in a dextran permeability assay"
The model's barrier readout.
Mesenchymal Shift of Aortic Endothelial Cells perturbs fidelity: moderate observes: cellular
Limitations: Marker induction and invasion suggest, but do not prove, a full endothelial-to-mesenchymal transition.
Show evidence (1 reference)
PMID:30455415 SUPPORT In Vitro
"Other phenotypes seen included induction of expression of α-SMA and Snail1 mRNA and cellular elongation and invasion."
The model's mesenchymal readouts.
🐁

Animal Models

3
Robo4 knockout mouse (Robo4tm1Lex)
Homozygous knockout mice develop a low-penetrance, male-predominant combination of aortic valve thickening, BAV, valve stenosis or regurgitation and ascending aortic aneurysm; heterozygotes were unaffected.
Species
Mouse
Genotype
Robo4tm1Lex/tm1Lex (exons 1-3 deleted)
Publication
PMID:30455415
Pathograph links
Abnormal Aortic Valve Development partially recapitulates fidelity: moderate observes: organism
Limitations: Only homozygous animals were affected, whereas human carriers are heterozygous; penetrance at 20 weeks was 5/28 males and 2/18 females.
Show evidence (2 references)
PMID:30455415 SUPPORT Model Organism
"Overall, at 20 weeks of age, 5/28 (17.9%) male and 2/18 (11.1%) female Robo4tm1Lex/tm1Lex mice were affected compared to 0/22 (0%) and 0/19 (0%) Robo4+/+ males and females, respectively"
Low-penetrance cardiovascular phenotype in homozygous knockouts.
+ 1 more reference
Robo4 exon 13 splice knock-in mouse (Robo4Skip13)
Knock-in of the mouse equivalent of the family 1 splice-donor variant causes exon 13 skipping and an incompletely penetrant valve and ascending-aorta phenotype, including in some heterozygous males.
Species
Mouse
Genotype
Robo4 c.2089+1G>T knock-in (Robo4Skip13)
Publication
PMID:30455415
Pathograph links
ROBO4 Loss of Function recapitulates fidelity: high observes: molecular
Show evidence (1 reference)
PMID:30455415 SUPPORT Model Organism
"We conclude that the Robo4Skip13 mutation alters pre-mRNA splicing with significant representation of mature mRNA lacking exon 13."
Reproduces the splicing defect of the human family 1 allele.
Abnormal Aortic Valve Development partially recapitulates fidelity: moderate observes: organism
Limitations: Penetrance at 20 weeks was 1/31 heterozygous and 4/35 homozygous males; the knock-in also activates a cryptic donor not described in patients.
Show evidence (1 reference)
PMID:30455415 SUPPORT Model Organism
"Like the knockout mice, Robo4Skip13 mice presented with an incompletely penetrant complex cardiovascular phenotype that included aortic valve defects and aortic valve dysfunction and AscAA."
Valve and aortic phenotype in the splice knock-in.
robo4 frameshift zebrafish (robo4 delta7)
Adult heterozygous and homozygous mutants show more ventriculo-bulbar valve regurgitation or turbulence than wild type; no vascular enlargement was observed.
Species
Zebrafish
Genotype
robo4 exon 6 seven-nucleotide deletion (robo4Δ7)
Publication
PMID:30455415
Pathograph links
Abnormal Aortic Valve Development partially recapitulates fidelity: low observes: organism
Limitations: The ventriculo-bulbar valve is not an aortic valve, the readout is valve function rather than morphology, and no aneurysm phenotype was seen.
Show evidence (1 reference)
PMID:30455415 SUPPORT Model Organism
"Thus, targeted disruption of robo4 in zebrafish perturbs outflow tract function."
Outflow-tract valve dysfunction in robo4 mutant fish.
{ }

Source YAML

click to show 
name: Aortic Valve Disease 3
creation_date: "2026-10-11T00:00:00Z"
category: Mendelian
description: >-
  Aortic valve disease 3 is an autosomal dominant, incompletely penetrant
  ROBO4-associated valvulo-aortopathy in which bicuspid aortic valve, aortic
  valve stenosis, and aneurysm of the aortic root and/or ascending aorta occur
  alone or in combination, with atrial septal defect in one reported family.
  The proposed mechanism is endothelial: loss of ROBO4 function in cultured
  aortic endothelial cells weakens the endothelial barrier and shifts the cells
  toward a mesenchymal, invasive state, and aneurysm tissue from an affected
  individual shows plasma albumin penetrating the intima with fibroproliferative
  remodeling and elastic-fiber fragmentation of the superficial media. The
  disease rests on two segregating families, a rare-variant enrichment in a
  BAV/ascending-aneurysm cohort, and mouse and zebrafish models; ClinGen
  classifies the gene-disease relationship as Moderate.
disease_term:
  preferred_term: aortic valve disease 3
  term:
    id: MONDO:0032783
    label: aortic valve disease 3
synonyms:
- AOVD3
categories:
- Congenital Heart Disease
- Valvuloaortopathy
mappings:
  mondo_mappings:
  - term:
      id: MONDO:0032783
      label: aortic valve disease 3
    mapping_predicate: skos:exactMatch
    mapping_source: MONDO
    mapping_justification: Primary MONDO disease identifier for the ROBO4-defined aortic valve disease.
inheritance:
- name: Autosomal dominant
  inheritance_term:
    preferred_term: Autosomal dominant inheritance
    term:
      id: HP:0000006
      label: Autosomal dominant inheritance
  penetrance: INCOMPLETE
  expressivity: VARIABLE
  description: >-
    Heterozygous ROBO4 variants segregated with disease in two families. In the
    larger family two clinically unaffected female relatives carried the splice
    variant, and carriers showed BAV with ascending aneurysm, isolated BAV, or
    isolated aortic aneurysm. Seven of the eight affected members of that family
    were male. No numerical penetrance estimate exists.
  evidence:
  - reference: PMID:30455415
    reference_title: ROBO4 variants predispose individuals to bicuspid aortic valve and thoracic aortic aneurysm.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Here, we report the identification of variants in ROBO4 (which encodes a
      factor known to contribute to endothelial performance) that segregate with
      disease in two families.
    explanation: >-
      Segregation of heterozygous ROBO4 variants with disease in two families is
      the basis for the dominant inheritance pattern.
  - reference: PMID:30455415
    reference_title: ROBO4 variants predispose individuals to bicuspid aortic valve and thoracic aortic aneurysm.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Two clinically unaffected female family members were heterozygous for the
      ROBO4 splice-site mutation.
    explanation: >-
      Unaffected heterozygous carriers in family 1 establish incomplete
      penetrance.
  - reference: PMID:30455415
    reference_title: ROBO4 variants predispose individuals to bicuspid aortic valve and thoracic aortic aneurysm.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      a concept further supported by the presence of either BAV/AscAA, isolated
      BAV, or isolated AscAA in family members segregating the same ROBO4
      mutation
    explanation: >-
      Different manifestations among carriers of one variant establish variable
      expressivity.
  - reference: CGGV:assertion_3531e2eb-71cd-446c-8956-acb15c3adc7b-2025-01-24T170000.000Z
    reference_title: ROBO4 / aortic valve disease 3 (Moderate)
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      The condition is incompletely penetrant (both in terms of aortic valve
      disease and aortic aneurysm) with greater penetrance in males compared to
      females.
    explanation: >-
      The ClinGen evidence summary for this gene-disease pair records incomplete
      penetrance with a male bias.
pathophysiology:
- name: ROBO4 Loss of Function
  description: >-
    Heterozygous germline ROBO4 variants reduce or structurally disrupt the
    endothelial ROBO4 receptor. The family 1 splice-donor variant causes in-frame
    skipping of exon 13, removing 36 amino acids from the intracellular domain;
    the family 2 missense variant p.Arg64Cys changes a conserved residue in the
    first extracellular Ig-like domain. Silencing and mutant-expression
    experiments point to loss of function, by haploinsufficiency or an
    antimorphic effect of mutant protein, as the pathogenic mechanism.
  biological_scale: MOLECULAR
  genes:
  - preferred_term: ROBO4
    modifier: DECREASED
    term:
      id: hgnc:17985
      label: ROBO4
  molecular_functions:
  - preferred_term: ROBO4 endothelial receptor activity
    term:
      id: GO:0038023
      label: signaling receptor activity
  notes: >-
    The molecular function is bound without a modifier. The discovery paper
    found the familial missense variants spread along the whole protein and
    argues against loss of any domain-specific function (dimerization, partner
    binding, SLIT recruitment), so which aspect of ROBO4 receptor activity the
    variants reduce has not been established. GO:0038023 is the curated GO
    molecular function for ROBO4 (Q8WZ75).
  evidence:
  - reference: PMID:18345009
    reference_title: Robo4 stabilizes the vascular network by inhibiting pathologic angiogenesis and endothelial hyperpermeability.
    supports: SUPPORT
    directness: INDIRECT
    evidence_source: IN_VITRO
    snippet: >-
      Activation of Robo4 by Slit2 inhibits vascular endothelial growth factor
      (VEGF)-165-induced migration, tube formation and permeability in vitro
    explanation: >-
      Establishes ROBO4 as an endothelial receptor whose activation suppresses
      VEGF-induced permeability, which supports the molecular function bound on
      this node. It is not a study of the disease variants.
  - reference: PMID:30455415
    reference_title: ROBO4 variants predispose individuals to bicuspid aortic valve and thoracic aortic aneurysm.
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: >-
      Amplification and sequencing of cDNA derived from patient and control
      fibroblasts showed that the splice-site mutation results in the skipping of
      the 108 base pairs encoding exon 13 of ROBO4, resulting in an in-frame
      transcript encoding a protein isoform missing 36 amino acids from the
      intracellular domain
    explanation: >-
      Cultured patient fibroblasts show the molecular consequence of the
      family 1 splice variant.
  - reference: PMID:30455415
    reference_title: ROBO4 variants predispose individuals to bicuspid aortic valve and thoracic aortic aneurysm.
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: >-
      These data suggest that loss-of-function (by functional haploinsufficiency
      or the antimorphic effects of overexpressed mutant protein) is the relevant
      pathogenic mechanism.
    explanation: >-
      The authors' conclusion from the cultured endothelial-cell experiments
      that the variants act through loss of function.
  - reference: CGGV:assertion_3531e2eb-71cd-446c-8956-acb15c3adc7b-2025-01-24T170000.000Z
    reference_title: ROBO4 / aortic valve disease 3 (Moderate)
    supports: SUPPORT
    evidence_source: OTHER
    snippet: The mechanism of pathogenicity appears to be loss of function.
    explanation: ClinGen's curation records loss of function as the apparent mechanism.
  downstream:
  - target: Impaired Endothelial Barrier Function
    description: >-
      ROBO4 silencing, or expression of either familial variant, made cultured
      human aortic endothelial monolayers more permeable.
    causal_link_type: DIRECT
    evidence:
    - reference: PMID:30455415
      reference_title: ROBO4 variants predispose individuals to bicuspid aortic valve and thoracic aortic aneurysm.
      supports: SUPPORT
      evidence_source: IN_VITRO
      snippet: >-
        Either ROBO4 silencing or expression of ROBO4 variants resulted in loss
        of endothelial barrier function in a dextran permeability assay
      explanation: >-
        Directly perturbing ROBO4 in human aortic endothelial cells produces the
        barrier defect.
  - target: Mesenchymal Shift of Aortic Endothelial Cells
    description: >-
      The same perturbations induced mesenchymal markers, cell elongation and
      invasion. The paper reports this in parallel with the barrier defect and
      does not show that one causes the other.
    causal_link_type: DIRECT
    evidence:
    - reference: PMID:30455415
      reference_title: ROBO4 variants predispose individuals to bicuspid aortic valve and thoracic aortic aneurysm.
      supports: SUPPORT
      evidence_source: IN_VITRO
      snippet: >-
        Other phenotypes seen included induction of expression of α-SMA and
        Snail1 mRNA and cellular elongation and invasion.
      explanation: >-
        ROBO4 silencing or mutant expression in cultured aortic endothelial
        cells induces a mesenchymal expression program and invasive behavior.
  - target: Abnormal Aortic Valve Development
    description: >-
      Loss of Robo4 in mice produces aortic valve thickening, bicuspid valves and
      valve dysfunction. The intervening developmental steps were not studied;
      ROBO4 is expressed in the endocardial cushions where the valve forms.
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    evidence:
    - reference: PMID:30455415
      reference_title: ROBO4 variants predispose individuals to bicuspid aortic valve and thoracic aortic aneurysm.
      supports: SUPPORT
      evidence_source: MODEL_ORGANISM
      snippet: >-
        Homozygous Robo4tm1Lex/tm1Lex knockout mice exhibited a complex
        cardiovascular phenotype that includes a combination of aortic valve
        thickening with or without BAV, aortic valve stenosis and/or
        regurgitation and/or AscAA.
      explanation: >-
        Homozygous loss of Robo4 in the mouse produces valve malformation; the
        human disease is heterozygous, so this is model-organism support.
- name: Impaired Endothelial Barrier Function
  description: >-
    ROBO4-deficient aortic endothelium loses barrier function, with reduced
    expression of the tight-junction protein TJP1 and the adherens-junction
    protein VE-cadherin. In aneurysm tissue from an affected family member,
    endothelial ROBO4 staining was diminished and plasma albumin penetrated the
    aortic intima, whereas it stayed at the endothelial surface in control aorta.
  biological_scale: CELLULAR
  cell_types:
  - preferred_term: aortic endothelial cell
    term:
      id: CL:0002544
      label: aortic endothelial cell
  biological_processes:
  - preferred_term: establishment of endothelial barrier
    modifier: DECREASED
    term:
      id: GO:0061028
      label: establishment of endothelial barrier
  locations:
  - preferred_term: ascending aorta
    term:
      id: UBERON:0001496
      label: ascending aorta
  evidence:
  - reference: PMID:30455415
    reference_title: ROBO4 variants predispose individuals to bicuspid aortic valve and thoracic aortic aneurysm.
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: >-
      Loss of barrier function associated with down regulation of expression of
      TJP1 and VE-cadherin mRNA and protein, indicative of loss of tight- and
      adherens-junction integrity, respectively
    explanation: >-
      Junctional protein loss accompanies the barrier defect in cultured human
      aortic endothelial cells.
  - reference: PMID:30455415
    reference_title: ROBO4 variants predispose individuals to bicuspid aortic valve and thoracic aortic aneurysm.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      immunostaining for albumin was restricted to the endothelial surface in
      control aorta, but substantial penetration into the aortic intima was
      observed in patient tissue
    explanation: >-
      Resected aneurysm tissue from one affected individual shows increased
      permeability in vivo. This is a single patient compared with a single
      control.
  - reference: PMID:30455415
    reference_title: ROBO4 variants predispose individuals to bicuspid aortic valve and thoracic aortic aneurysm.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      ROBO4 was strongly expressed in endothelial cells in control aorta as
      evidenced by co-localization with platelet endothelial cell adhesion
      molecule 1 (CD31) but was diminished in the endothelium in the BAV/AscAA
      sample
    explanation: >-
      Reduced endothelial ROBO4 in the patient's aneurysmal aorta.
  downstream:
  - target: Aortic Wall Medial Remodeling
    description: >-
      The authors infer from the patient tissue that barrier failure contributes
      to remodeling of the aortic media; the order of events was not tested.
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    evidence:
    - reference: PMID:30455415
      reference_title: ROBO4 variants predispose individuals to bicuspid aortic valve and thoracic aortic aneurysm.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      directness: INDIRECT
      snippet: >-
        Collectively, these data suggest that ROBO4 mutations disrupt
        endothelial cellular performance and barrier function, contributing to
        pathological remodeling of the aortic media.
      explanation: >-
        The causal link is the authors' interpretation of co-occurring findings
        in one patient's aneurysm tissue rather than an experiment.
- name: Mesenchymal Shift of Aortic Endothelial Cells
  description: >-
    ROBO4-deficient aortic endothelial cells express alpha-smooth muscle actin
    and SNAI1, elongate and invade collagen gels, a pattern the authors read as
    suggestive of endothelial-to-mesenchymal transition. In the patient's
    aneurysm, ROBO4-positive cells co-staining for alpha-smooth muscle actin
    were found in the aortic media. No single signaling pathway was identified:
    ROBO4 silencing gave a modest decline in BMP and Notch target-gene
    expression without altered TGF-beta responses.
  biological_scale: CELLULAR
  cell_types:
  - preferred_term: aortic endothelial cell
    term:
      id: CL:0002544
      label: aortic endothelial cell
  notes: >-
    No biological_processes binding. GO searched through ols:go with the
    queries "endothelial to mesenchymal" and "endothelial-mesenchymal"; both
    returned only GO:0140074 cardiac endothelial to mesenchymal transition and
    its three regulation terms. The cells studied were aortic endothelium, not
    cardiac endothelium, so the cardiac term would overstate the claim.
  evidence:
  - reference: PMID:30455415
    reference_title: ROBO4 variants predispose individuals to bicuspid aortic valve and thoracic aortic aneurysm.
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: >-
      Together, these results suggest that reduction or structural disruption of
      ROBO4 compromises endothelial identity and performance, as well as its
      capacity to suppress transition to a mesenchymal invasive character and
      synthetic repertoire.
    explanation: >-
      The authors' synthesis of the cultured-cell results.
  - reference: PMID:30455415
    reference_title: ROBO4 variants predispose individuals to bicuspid aortic valve and thoracic aortic aneurysm.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      the aneurysm tissue uniquely showed infiltration of ROBO4+ cells into the
      aortic media with co-staining for α-SMA
    explanation: >-
      A tissue observation in one patient consistent with mesenchymal behavior
      of ROBO4-expressing cells in vivo.
  - reference: PMID:30455415
    reference_title: ROBO4 variants predispose individuals to bicuspid aortic valve and thoracic aortic aneurysm.
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: >-
      Assessment of expression of prototypical target genes suggested a modest
      decline in bone morphogenetic protein (BMP) and Notch activity without
      altered TGFβ responses upon ROBO4 silencing.
    explanation: >-
      Records that no single downstream pathway was shown to drive the
      mesenchymal shift.
  downstream:
  - target: Aortic Wall Medial Remodeling
    description: >-
      Proposed by the authors as a contributor alongside barrier failure; not
      tested experimentally.
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    evidence:
    - reference: PMID:30455415
      reference_title: ROBO4 variants predispose individuals to bicuspid aortic valve and thoracic aortic aneurysm.
      supports: SUPPORT
      evidence_source: IN_VITRO
      directness: INDIRECT
      snippet: >-
        This study focuses attention on endothelial cell biology in BAV/AscAA,
        with impairment of barrier function and/or dysregulation of mesenchymal
        transition potentially contributing to disease expression.
      explanation: >-
        A hypothesis stated in the discussion, drawn from the cell experiments.
- name: Aortic Wall Medial Remodeling
  description: >-
    Aneurysmal ascending aorta from an affected family member showed a
    fibroproliferative response with collagen accumulation in the intima and
    superficial media, and decreased elastin with fragmented, disarrayed elastic
    fibers in the superficial media.
  biological_scale: TISSUE
  locations:
  - preferred_term: ascending aorta
    term:
      id: UBERON:0001496
      label: ascending aorta
  evidence:
  - reference: PMID:30455415
    reference_title: ROBO4 variants predispose individuals to bicuspid aortic valve and thoracic aortic aneurysm.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Histologic analyses showed a strong fibroproliferative response in the
      intima and superficial medial layer of patient aorta, as evidenced by
      increased cellularity and the accumulation of collagen upon Masson's
      trichrome staining.
    explanation: Fibroproliferative remodeling in one patient's aneurysm tissue.
  - reference: PMID:30455415
    reference_title: ROBO4 variants predispose individuals to bicuspid aortic valve and thoracic aortic aneurysm.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      decreased elastin content and fragmentation and disarray of elastic fibers
      in the superficial media was revealed upon Verhoeff-Van Gieson (VVG)
      staining
    explanation: Elastic-fiber loss in the same patient's aneurysm tissue.
  downstream:
  - target: Aortic root aneurysm
    description: >-
      Medial remodeling was observed in aneurysmal tissue; that it produces the
      dilatation is inferred, not demonstrated for this disease.
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
  - target: Ascending tubular aorta aneurysm
    description: >-
      Medial remodeling was observed in aneurysmal tissue; that it produces the
      dilatation is inferred, not demonstrated for this disease.
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
- name: Abnormal Aortic Valve Development
  description: >-
    ROBO4 is expressed in the endocardium of the developing outflow-tract
    cushions and later in endothelial and interstitial cells of the developing
    aortic valve. Robo4-deficient mice develop valve thickening, bicuspid and
    occasionally quadricuspid valves, and valve stenosis or regurgitation. Valve
    pathology from an affected family member with BAV showed valve thickening
    with a fibroproliferative process.
  biological_scale: TISSUE
  cell_types:
  - preferred_term: endocardial cell
    term:
      id: CL:0002350
      label: endocardial cell
  biological_processes:
  - preferred_term: aortic valve morphogenesis
    modifier: ABNORMAL
    term:
      id: GO:0003180
      label: aortic valve morphogenesis
  locations:
  - preferred_term: aortic valve
    term:
      id: UBERON:0002137
      label: aortic valve
  evidence:
  - reference: PMID:30455415
    reference_title: ROBO4 variants predispose individuals to bicuspid aortic valve and thoracic aortic aneurysm.
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: >-
      We observed that mouse ROBO4 was expressed in the endocardial layer of the
      cushions and delamination zones at embryonic day 11.5
    explanation: Places ROBO4 in the cells that form the valve primordia.
  - reference: PMID:30455415
    reference_title: ROBO4 variants predispose individuals to bicuspid aortic valve and thoracic aortic aneurysm.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Pathology from one family member with BAV revealed valve thickening in
      association with a pronounced fibroproliferative process
    explanation: Valve pathology in one affected carrier.
  downstream:
  - target: Bicuspid aortic valve
    description: Abnormal valve formation yields a bicuspid valve in some carriers.
    causal_link_type: DIRECT
    evidence:
    - reference: PMID:30455415
      reference_title: ROBO4 variants predispose individuals to bicuspid aortic valve and thoracic aortic aneurysm.
      supports: SUPPORT
      evidence_source: MODEL_ORGANISM
      snippet: >-
        Homozygous Robo4tm1Lex/tm1Lex knockout mice exhibited a complex
        cardiovascular phenotype that includes a combination of aortic valve
        thickening with or without BAV, aortic valve stenosis and/or
        regurgitation and/or AscAA.
      explanation: Valve malformation including BAV in Robo4-deficient mice.
  - target: Aortic valve stenosis
    description: >-
      Thickened, malformed valves become stenotic. Mouse evidence; in family 2 a
      carrier had stenosis requiring surgery.
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    evidence:
    - reference: PMID:30455415
      reference_title: ROBO4 variants predispose individuals to bicuspid aortic valve and thoracic aortic aneurysm.
      supports: SUPPORT
      evidence_source: MODEL_ORGANISM
      snippet: >-
        Homozygous Robo4tm1Lex/tm1Lex knockout mice exhibited a complex
        cardiovascular phenotype that includes a combination of aortic valve
        thickening with or without BAV, aortic valve stenosis and/or
        regurgitation and/or AscAA.
      explanation: Valve thickening and stenosis co-occur in Robo4-deficient mice.
phenotypes:
- name: Aortic root aneurysm
  category: Cardiovascular
  description: >-
    Aneurysm at the sinuses of Valsalva was present in all eight affected
    members of family 1, with or without more distal ascending aneurysm. ClinGen
    notes that thoracic aneurysm occurs independently of BAV in ROBO4 carriers.
  phenotype_term:
    preferred_term: Aortic root aneurysm
    term:
      id: HP:0002616
      label: Aortic root aneurysm
  evidence:
  - reference: PMID:30455415
    reference_title: ROBO4 variants predispose individuals to bicuspid aortic valve and thoracic aortic aneurysm.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      In one large family (Family 1), eight individuals showed AoRA with or
      without DAscAA; two had associated BAV
    explanation: Aortic root aneurysm in all affected members of family 1.
  - reference: CGGV:assertion_3531e2eb-71cd-446c-8956-acb15c3adc7b-2025-01-24T170000.000Z
    reference_title: ROBO4 / aortic valve disease 3 (Moderate)
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      It is associated with aortic root aneurysm, ascending aortic aneurysm, and
      atrial septal defect (ASD) in some individuals.
    explanation: ClinGen's disease description lists aortic root aneurysm.
- name: Ascending tubular aorta aneurysm
  category: Cardiovascular
  description: >-
    Aneurysm of the ascending aorta distal to the sinuses accompanied root
    aneurysm in some members of family 1.
  phenotype_term:
    preferred_term: Ascending aortic aneurysm
    term:
      id: HP:0004970
      label: Ascending tubular aorta aneurysm
  evidence:
  - reference: PMID:30455415
    reference_title: ROBO4 variants predispose individuals to bicuspid aortic valve and thoracic aortic aneurysm.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      In one large family (Family 1), eight individuals showed AoRA with or
      without DAscAA; two had associated BAV
    explanation: Distal ascending aneurysm (DAscAA) in part of family 1.
  - reference: CGGV:assertion_3531e2eb-71cd-446c-8956-acb15c3adc7b-2025-01-24T170000.000Z
    reference_title: ROBO4 / aortic valve disease 3 (Moderate)
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      It is associated with aortic root aneurysm, ascending aortic aneurysm, and
      atrial septal defect (ASD) in some individuals.
    explanation: ClinGen's disease description lists ascending aortic aneurysm.
- name: Bicuspid aortic valve
  category: Cardiovascular
  description: >-
    Reported in two members of family 1 and in the affected son in family 2.
  phenotype_term:
    preferred_term: Bicuspid aortic valve
    term:
      id: HP:0001647
      label: Bicuspid aortic valve
  evidence:
  - reference: PMID:30455415
    reference_title: ROBO4 variants predispose individuals to bicuspid aortic valve and thoracic aortic aneurysm.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      In family 2, WES revealed a heterozygous ROBO4 missense variant (c.190C>T;
      p.Arg64Cys) in a woman, with atrial septal defect (ASD) and aortic valve
      stenosis (AVS) that required surgery, and her son with ASD, BAV and
      significant AVS
    explanation: BAV in the family 2 son.
  - reference: PMID:30455415
    reference_title: ROBO4 variants predispose individuals to bicuspid aortic valve and thoracic aortic aneurysm.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      In one large family (Family 1), eight individuals showed AoRA with or
      without DAscAA; two had associated BAV
    explanation: BAV in two members of family 1.
- name: Aortic valve stenosis
  category: Cardiovascular
  description: >-
    Present in both members of family 2, with surgery required in the mother.
    OMIM and ClinGen define the disease by aortic stenosis and/or bicuspid
    aortic valve.
  phenotype_term:
    preferred_term: Aortic valve stenosis
    term:
      id: HP:0001650
      label: Aortic valve stenosis
  evidence:
  - reference: PMID:30455415
    reference_title: ROBO4 variants predispose individuals to bicuspid aortic valve and thoracic aortic aneurysm.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      In family 2, WES revealed a heterozygous ROBO4 missense variant (c.190C>T;
      p.Arg64Cys) in a woman, with atrial septal defect (ASD) and aortic valve
      stenosis (AVS) that required surgery, and her son with ASD, BAV and
      significant AVS
    explanation: Aortic valve stenosis in both family 2 carriers.
  - reference: CGGV:assertion_3531e2eb-71cd-446c-8956-acb15c3adc7b-2025-01-24T170000.000Z
    reference_title: ROBO4 / aortic valve disease 3 (Moderate)
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      AOVD is characterized by aortic stenosis and/or bicuspid aortic valve
      (BAV).
    explanation: ClinGen's disease definition.
- name: Atrial septal defect
  category: Cardiovascular
  description: >-
    Reported in the mother and son of family 2 only. No mechanism linking ROBO4
    to atrial septation has been studied, so this phenotype has no upstream
    node.
  phenotype_term:
    preferred_term: Atrial septal defect
    term:
      id: HP:0001631
      label: Atrial septal defect
  evidence:
  - reference: PMID:30455415
    reference_title: ROBO4 variants predispose individuals to bicuspid aortic valve and thoracic aortic aneurysm.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      In family 2, WES revealed a heterozygous ROBO4 missense variant (c.190C>T;
      p.Arg64Cys) in a woman, with atrial septal defect (ASD) and aortic valve
      stenosis (AVS) that required surgery, and her son with ASD, BAV and
      significant AVS
    explanation: ASD in both family 2 carriers.
genetic:
- name: ROBO4
  gene_term:
    preferred_term: ROBO4
    term:
      id: hgnc:17985
      label: ROBO4
  association: Defining gene; ClinGen Moderate for autosomal dominant AOVD3
  variant_origin: GERMLINE
  gene_disease_validity:
  - validity_classification: MODERATE
    classified_by: CLINGEN
    external_id: CGGV:assertion_3531e2eb-71cd-446c-8956-acb15c3adc7b-2025-01-24T170000.000Z
    evidence:
    - reference: CGGV:assertion_3531e2eb-71cd-446c-8956-acb15c3adc7b-2025-01-24T170000.000Z
      reference_title: ROBO4 / aortic valve disease 3 (Moderate)
      supports: SUPPORT
      evidence_source: OTHER
      snippet: "ROBO4 | HGNC:17985 | aortic valve disease 3 | MONDO:0032783 | AD | Moderate"
      explanation: >-
        ClinGen Congenital Heart Disease GCEP classifies ROBO4-aortic valve
        disease 3 as Moderate for autosomal dominant inheritance.
  notes: >-
    relationship_type is deliberately left unset. The schema defines CAUSATIVE
    as corresponding to ClinGen Definitive or Strong, and ClinGen rates this
    pair Moderate; no other GeneDiseaseRelationshipEnum value describes a
    defining gene with moderate validity. In the discovery study 13 of 736
    BAV/ascending-aneurysm probands (1.77%) carried a filtered rare ROBO4 variant
    against one of 376 controls (P = 0.0432). A later study found no significant
    ROBO4 contribution to BAV in a heritable thoracic aortic disease cohort.
  variants:
  - name: ROBO4 c.2056+1G>T
    description: >-
      Splice-donor variant (NM_019055.5) segregating in family 1, carried by all
      eight affected members and two unaffected women; causes in-frame skipping
      of exon 13.
    evidence:
    - reference: PMID:30455415
      reference_title: ROBO4 variants predispose individuals to bicuspid aortic valve and thoracic aortic aneurysm.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        We confirmed that all eight affected family members carried the
        mutation.
      explanation: Segregation of the splice variant with disease in family 1.
  - name: ROBO4 c.190C>T (p.Arg64Cys)
    description: >-
      Missense variant in the first Ig-like extracellular domain, found in an
      affected mother and son (family 2) and in one further unrelated proband.
    evidence:
    - reference: PMID:30455415
      reference_title: ROBO4 variants predispose individuals to bicuspid aortic valve and thoracic aortic aneurysm.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        The missense mutations observed in the targeted sequencing cohort
        include an independent example of the p.Arg64Cys variant observed in
        Family 2.
      explanation: Recurrence of p.Arg64Cys in an unrelated proband.
  evidence:
  - reference: PMID:30455415
    reference_title: ROBO4 variants predispose individuals to bicuspid aortic valve and thoracic aortic aneurysm.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Collectively, among familial and individual probands (WES and targeted
      sequencing), 13/736 (1.77%) had a ROBO4 variant that passed a priori
      filtering constraints while one rare (absent from ExAC) missense mutation
      was observed among 376 rigorously phenotyped controls
    explanation: Rare-variant enrichment in BAV/ascending-aneurysm probands.
  - reference: PMID:32748548
    reference_title: "Rare deleterious variants of NOTCH1, GATA4, SMAD6, and ROBO4 are enriched in BAV with early onset complications but not in BAV with heritable thoracic aortic disease."
    supports: REFUTE
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Rare variants of NOTCH1, ROBO4, SMAD6, or GATA4 do not significantly
      contribute to BAV in cohorts with HTAD.
    explanation: >-
      A burden analysis found no significant ROBO4 contribution to BAV in a
      heritable thoracic aortic disease cohort. This bears on how much of BAV
      with aortic disease ROBO4 explains, not on segregation in the original
      families.
  - reference: PMID:32748548
    reference_title: "Rare deleterious variants of NOTCH1, GATA4, SMAD6, and ROBO4 are enriched in BAV with early onset complications but not in BAV with heritable thoracic aortic disease."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Rare NOTCH1 and ROBO4 variants were also enriched in the EBAV cohort, but
      this was not statistically significant due to limited power in this small
      data set.
    explanation: >-
      A non-significant trend toward ROBO4 enrichment in early-onset BAV
      complications (63 probands).
diagnosis:
- name: Transthoracic Echocardiography
  description: >-
    Echocardiography defines valve morphology and function and measures the
    aortic root and ascending aorta. This is general BAV guidance, not
    ROBO4-specific.
  diagnosis_term:
    preferred_term: echocardiography
    term:
      id: NCIT:C16525
      label: Echocardiography Test
  evidence:
  - reference: PMID:36322642
    reference_title: "2022 ACC/AHA Guideline for the Diagnosis and Management of Aortic Disease: A Report of the American Heart Association/American College of Cardiology Joint Committee on Clinical Practice Guidelines."
    supports: SUPPORT
    evidence_source: OTHER
    quote_role: REVIEW_SYNTHESIS
    snippet: >-
      In patients with a BAV, TTE is indicated to evaluate valve morphology and
      function, to evaluate the diameter of the aortic root and ascending aorta,
      and to evaluate for aortic coarctation and other associated cardiovascular
      defects.
    explanation: Guideline recommendation for BAV generally.
- name: Echocardiographic Screening of First-Degree Relatives
  description: >-
    Because penetrance is incomplete and carriers may have isolated valve or
    aortic disease, relatives are screened by imaging. The guideline
    recommendation applies to BAV with aortic dilatation generally.
  diagnosis_term:
    preferred_term: echocardiography
    term:
      id: NCIT:C16525
      label: Echocardiography Test
  evidence:
  - reference: PMID:36322642
    reference_title: "2022 ACC/AHA Guideline for the Diagnosis and Management of Aortic Disease: A Report of the American Heart Association/American College of Cardiology Joint Committee on Clinical Practice Guidelines."
    supports: SUPPORT
    evidence_source: OTHER
    quote_role: REVIEW_SYNTHESIS
    snippet: >-
      In patients with a BAV and a dilated aortic root or ascending aorta,
      screening of all first-degree relatives by TTE is recommended to evaluate
      for the presence of a BAV, dilation of the aortic root and ascending
      aorta, or both
    explanation: Guideline basis for family imaging.
- name: Multigene Panel Testing
  description: >-
    ROBO4 is listed among genes for BAV with thoracic aortic aneurysm in the
    2022 ACC/AHA aortic guideline's gene table.
  evidence:
  - reference: PMID:36322642
    reference_title: "2022 ACC/AHA Guideline for the Diagnosis and Management of Aortic Disease: A Report of the American Heart Association/American College of Cardiology Joint Committee on Clinical Practice Guidelines."
    supports: SUPPORT
    evidence_source: OTHER
    quote_role: REVIEW_SYNTHESIS
    snippet: "BAV with TAA | TGFBR2, MAT2A, GATA5, SMAD6, LOX, ROBO4, TBX20"
    explanation: The guideline gene table names ROBO4 for BAV with thoracic aortic aneurysm.
treatments:
- name: Aortic Valve Replacement
  description: >-
    Surgical replacement for severe aortic valve stenosis; the affected mother in
    family 2 required valve surgery. This treats the lesion, not the inherited
    susceptibility.
  therapeutic_modality: SURGERY
  treatment_term:
    preferred_term: aortic valve replacement
    term:
      id: NCIT:C50815
      label: Aortic Valve Replacement
  target_mechanisms:
  - target: Aortic valve stenosis
  evidence:
  - reference: PMID:30455415
    reference_title: ROBO4 variants predispose individuals to bicuspid aortic valve and thoracic aortic aneurysm.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      In family 2, WES revealed a heterozygous ROBO4 missense variant (c.190C>T;
      p.Arg64Cys) in a woman, with atrial septal defect (ASD) and aortic valve
      stenosis (AVS) that required surgery
    explanation: Valve surgery in a ROBO4 carrier with stenosis.
- name: Prophylactic Aortic Root and Ascending Aorta Replacement
  description: >-
    Surgical replacement of the dilated aortic root and/or ascending aorta at
    guideline diameter thresholds for BAV-associated aortopathy. Thresholds are
    general BAV guidance and have not been validated for ROBO4 carriers.
  therapeutic_modality: SURGERY
  treatment_term:
    preferred_term: aortic root and ascending aorta replacement surgery
    term:
      id: NCIT:C15329
      label: Surgical Procedure
  target_mechanisms:
  - target: Aortic root aneurysm
  - target: Ascending tubular aorta aneurysm
  evidence:
  - reference: PMID:36322642
    reference_title: "2022 ACC/AHA Guideline for the Diagnosis and Management of Aortic Disease: A Report of the American Heart Association/American College of Cardiology Joint Committee on Clinical Practice Guidelines."
    supports: SUPPORT
    evidence_source: OTHER
    quote_role: REVIEW_SYNTHESIS
    snippet: >-
      In patients with a BAV and a diameter of the aortic root, ascending aorta,
      or both of ≥5.5 cm, surgery to replace the aortic root, ascending aorta,
      or both is recommended.
    explanation: Guideline surgical threshold for BAV-associated aortopathy.
animal_models:
- name: Robo4 knockout mouse (Robo4tm1Lex)
  species: Mouse
  genotype: Robo4tm1Lex/tm1Lex (exons 1-3 deleted)
  publication: PMID:30455415
  description: >-
    Homozygous knockout mice develop a low-penetrance, male-predominant
    combination of aortic valve thickening, BAV, valve stenosis or regurgitation
    and ascending aortic aneurysm; heterozygotes were unaffected.
  modeled_mechanisms:
  - target: Abnormal Aortic Valve Development
    relationship: PARTIALLY_RECAPITULATES
    fidelity: MODERATE
    model_scale: ORGANISM
    limitations: >-
      Only homozygous animals were affected, whereas human carriers are
      heterozygous; penetrance at 20 weeks was 5/28 males and 2/18 females.
    evidence:
    - reference: PMID:30455415
      reference_title: ROBO4 variants predispose individuals to bicuspid aortic valve and thoracic aortic aneurysm.
      supports: SUPPORT
      evidence_source: MODEL_ORGANISM
      snippet: >-
        Overall, at 20 weeks of age, 5/28 (17.9%) male and 2/18 (11.1%) female
        Robo4tm1Lex/tm1Lex mice were affected compared to 0/22 (0%) and 0/19
        (0%) Robo4+/+ males and females, respectively
      explanation: Low-penetrance cardiovascular phenotype in homozygous knockouts.
    - reference: PMID:30455415
      reference_title: ROBO4 variants predispose individuals to bicuspid aortic valve and thoracic aortic aneurysm.
      supports: SUPPORT
      evidence_source: MODEL_ORGANISM
      snippet: >-
        None of the evaluated heterozygotes (Robo4tm1Lex/+) presented with any
        structural or functional abnormality.
      explanation: Grounds the heterozygosity limitation.
- name: Robo4 exon 13 splice knock-in mouse (Robo4Skip13)
  species: Mouse
  genotype: Robo4 c.2089+1G>T knock-in (Robo4Skip13)
  publication: PMID:30455415
  description: >-
    Knock-in of the mouse equivalent of the family 1 splice-donor variant causes
    exon 13 skipping and an incompletely penetrant valve and ascending-aorta
    phenotype, including in some heterozygous males.
  modeled_mechanisms:
  - target: ROBO4 Loss of Function
    relationship: RECAPITULATES
    fidelity: HIGH
    model_scale: MOLECULAR
    evidence:
    - reference: PMID:30455415
      reference_title: ROBO4 variants predispose individuals to bicuspid aortic valve and thoracic aortic aneurysm.
      supports: SUPPORT
      evidence_source: MODEL_ORGANISM
      snippet: >-
        We conclude that the Robo4Skip13 mutation alters pre-mRNA splicing with
        significant representation of mature mRNA lacking exon 13.
      explanation: Reproduces the splicing defect of the human family 1 allele.
  - target: Abnormal Aortic Valve Development
    relationship: PARTIALLY_RECAPITULATES
    fidelity: MODERATE
    model_scale: ORGANISM
    limitations: >-
      Penetrance at 20 weeks was 1/31 heterozygous and 4/35 homozygous males;
      the knock-in also activates a cryptic donor not described in patients.
    evidence:
    - reference: PMID:30455415
      reference_title: ROBO4 variants predispose individuals to bicuspid aortic valve and thoracic aortic aneurysm.
      supports: SUPPORT
      evidence_source: MODEL_ORGANISM
      snippet: >-
        Like the knockout mice, Robo4Skip13 mice presented with an incompletely
        penetrant complex cardiovascular phenotype that included aortic valve
        defects and aortic valve dysfunction and AscAA.
      explanation: Valve and aortic phenotype in the splice knock-in.
- name: robo4 frameshift zebrafish (robo4 delta7)
  species: Zebrafish
  genotype: robo4 exon 6 seven-nucleotide deletion (robo4Δ7)
  publication: PMID:30455415
  description: >-
    Adult heterozygous and homozygous mutants show more ventriculo-bulbar valve
    regurgitation or turbulence than wild type; no vascular enlargement was
    observed.
  modeled_mechanisms:
  - target: Abnormal Aortic Valve Development
    relationship: PARTIALLY_RECAPITULATES
    fidelity: LOW
    model_scale: ORGANISM
    limitations: >-
      The ventriculo-bulbar valve is not an aortic valve, the readout is
      valve function rather than morphology, and no aneurysm phenotype was seen.
    evidence:
    - reference: PMID:30455415
      reference_title: ROBO4 variants predispose individuals to bicuspid aortic valve and thoracic aortic aneurysm.
      supports: SUPPORT
      evidence_source: MODEL_ORGANISM
      snippet: Thus, targeted disruption of robo4 in zebrafish perturbs outflow tract function.
      explanation: Outflow-tract valve dysfunction in robo4 mutant fish.
experimental_models:
- name: ROBO4-silenced or mutant-expressing human aortic endothelial cells
  experimental_model_type: PRIMARY_CELL_CULTURE
  organism:
    preferred_term: Homo sapiens
    term:
      id: NCBITaxon:9606
      label: Homo sapiens
  cell_types:
  - preferred_term: aortic endothelial cell
    term:
      id: CL:0002544
      label: aortic endothelial cell
  cell_source: Commercial primary human aortic endothelial cells, passages 2-6
  culture_system: Monolayers on porous inserts and cell aggregates on collagen gels
  publication: PMID:30455415
  description: >-
    Cells were treated with ROBO4 siRNA or transiently transfected with
    wild-type, exon 13-deleted or p.Arg64Cys ROBO4 constructs, then assayed for
    dextran permeability, junctional markers, mesenchymal markers, shape and
    invasion.
  modeled_mechanisms:
  - target: Impaired Endothelial Barrier Function
    relationship: PERTURBS
    fidelity: MODERATE
    model_scale: CELLULAR
    limitations: >-
      Transient overexpression in static culture, without flow, valve tissue
      context or lifetime exposure.
    evidence:
    - reference: PMID:30455415
      reference_title: ROBO4 variants predispose individuals to bicuspid aortic valve and thoracic aortic aneurysm.
      supports: SUPPORT
      evidence_source: IN_VITRO
      snippet: >-
        Either ROBO4 silencing or expression of ROBO4 variants resulted in loss
        of endothelial barrier function in a dextran permeability assay
      explanation: The model's barrier readout.
  - target: Mesenchymal Shift of Aortic Endothelial Cells
    relationship: PERTURBS
    fidelity: MODERATE
    model_scale: CELLULAR
    limitations: >-
      Marker induction and invasion suggest, but do not prove, a full
      endothelial-to-mesenchymal transition.
    evidence:
    - reference: PMID:30455415
      reference_title: ROBO4 variants predispose individuals to bicuspid aortic valve and thoracic aortic aneurysm.
      supports: SUPPORT
      evidence_source: IN_VITRO
      snippet: >-
        Other phenotypes seen included induction of expression of α-SMA and
        Snail1 mRNA and cellular elongation and invasion.
      explanation: The model's mesenchymal readouts.
notes: >-
  No GeneReviews chapter names this disease. A 2026 case report of congenital
  coarctation with BAV in a woman carrying ROBO4 p.Thr232Met was not curated as
  a phenotype: it is a single individual with no segregation data. Aortic
  regurgitation is reported only in the mouse and zebrafish models and is not
  listed as a human phenotype. No prevalence estimate exists; the 1.77% figure
  is a variant yield in a selected BAV/aneurysm cohort, not a disease
  frequency.
📚

References & Deep Research

Deep Research

1

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

Evaluations and curation notes (1)

Create: Aortic Valve Disease 3 · 2026-10-11T20:27:14Z · View source

Created the ROBO4 aortic valve disease 3 entry (MONDO:0032783) from the Perplexity deep-research report, the only report used. just preflight-dr returned PASS (ROBO4 mentioned 50 times, OMIM 618496 matches). just check-genereviews --online found no GeneReviews chapter. Nearly all disease-specific content rests on one paper, Gould et al. 2019 (PMID:30455415): two segregating families, a 13/736 rare-variant enrichment, cultured human aortic endothelial cell experiments, one patient's aneurysm histology, and Robo4 knockout, splice knock-in mouse and robo4 zebrafish models. evidence_source is set per item to separate patient, cultured-cell and animal findings. The ClinGen record (CGGV assertion 3531e2eb, Moderate, AD) was cached and recorded verbatim as a gene_disease_validity assertion; relationship_type is left unset because the schema ties CAUSATIVE to Definitive or Strong. Musfee et al. 2020 (PMID:32748548) is cited as REFUTE for the lack of significant ROBO4 burden in a heritable thoracic aortic disease cohort. General BAV diagnosis and surgery recommendations cite the 2022 ACC/AHA aortic guideline (PMID:36322642), whose gene table names ROBO4. A 2026 single-case coarctation report (PMID:41613935) was read and not curated as a phenotype. Atrial septal defect is left without an upstream mechanism node. Validation: just validate passed (51/51 snippets), validate-terms, check-entity-refs, check-causal-targets, check-duplicate-keys and check-block-scalar-comments clean.

Perplexity ▸
Aortic valve disease 3 (AOVD3): disease-characteristics research report
sonar-deep-research 57 citations 2026-10-11T20:09:52.474507

Aortic valve disease 3 (AOVD3): disease-characteristics research report

Aortic valve disease 3 (AOVD3; MONDO:0032783; OMIM:618496) is a proposed autosomal-dominant, ROBO4-associated cardiovascular disorder. Its reported manifestations include bicuspid aortic valve (BAV), aortic valve stenosis, aneurysm of the aortic root or ascending aorta, and, in one family, atrial septal defect. The principal evidence is a 2019 study of two families supported by cell and animal experiments. The gene–disease association should not be entered as unequivocally established: a GenCC submission classifies ROBO4–AOVD3 evidence as limited, and interpretation of at least one original familial variant remains disputed. [3][31][47][46]

Evidence notation used below: human denotes patient, family, or cohort observations; experimental denotes cultured-cell or animal findings; inference denotes a plausible link not directly established for AOVD3. PMID-linked primary articles are identified alongside citations. General BAV data are explicitly distinguished from ROBO4-specific data.

1. Disease information and identifiers

Identifier or name Entry and interpretation
Preferred name Aortic valve disease 3; AOVD3. [73]
MONDO MONDO:0032783. [73]
OMIM 618496, phenotype; 607528, ROBO4 gene. [3]
MedGen 1681142; UMLS concept C5193127. [73]
Other names “Aortic valve disease-3”; MedGen also indexes “aortic valve stenosis” and “bicuspid aortic valve.” The latter two describe features, not unique synonyms for this genetic subtype. [73]
MeSH D000082862, Aortic Valve Disease, a broader descriptor; not AOVD3-specific. [286]
ICD-10-CM No verified AOVD3-specific code. Code the documented manifestation: Q23.81 for BAV, Q23.0 for congenital aortic-valve stenosis, or I35.0 for nonrheumatic aortic-valve stenosis when applicable. Q23.81 has been effective since October 1, 2024. Coding depends on the clinician’s documentation; these codes are not interchangeable genetic diagnoses. [316][329][288]
ICD-11; Orphanet disease number No AOVD3-specific identifier verified in the reviewed sources.

This report synthesizes aggregated disease resources and published research, not individual-level electronic health records. Published family descriptions and tissue experiments originate from individual participants, but they do not constitute a population registry. OMIM’s concise description is: “Aortic valve disease-3 (AOVD3) is characterized by aortic stenosis and/or bicuspid aortic valve (BAV), associated in some patients with aneurysm of the aortic root and/or ascending aorta.” [3][31]

Principal primary source: Gould and colleagues, Nature Genetics 51:42–50 (published online November 19, 2018; January 2019 issue), PMID:30455415, DOI 10.1038/s41588-018-0265-y, https://pubmed.ncbi.nlm.nih.gov/30455415/. Its abstract states: “we report the identification of variants in ROBO4 … that segregate with disease in two families.” [32][31]

2. Etiology: causes, risks, protection, and interactions

Proposed initiating cause. Heterozygous germline ROBO4 variants are the defining genetic hypothesis for AOVD3. In the original families, one variant disrupts exon-13 splicing; another changes the extracellular receptor residue Arg64. The phenotype is not synonymous with every case of BAV: BAV has many genetic and non-genetic contributors, and current ROBO4 evidence does not justify assigning AOVD3 to a person solely because BAV is present. [31][3][47][84]

Factor AOVD3-specific finding or evidence boundary
Family history and genotype Transmission in the two reported families was compatible with autosomal dominance. Two apparently unaffected female carriers in the larger family establish incomplete observed penetrance; absence of imaging in some ostensibly unaffected relatives is a general limitation of BAV-family research. Human; PMID:30455415. [3][31][110]
Sex Seven of eight affected members of the larger original family were male. This is a small, ascertainment-dependent family count, not an AOVD3 population sex ratio. Human; PMID:30455415. [3][31]
Other genes NOTCH1, SMAD6, and other BAV/aneurysm genes are alternative etiologies or candidate co-contributors, not demonstrated AOVD3 modifier genes. A 2024 BAV exome study found multiple candidate variants in some probands, but did not establish an AOVD3-specific modifier. Human; PMID:39226896. [21][110]
Age, hypertension, smoking, hemodynamic load Clinically relevant to aortic or valvular disease management; no quantified interaction with a specific AOVD3 allele has been established. Blood-pressure control and smoking cessation are general thoracic-aneurysm measures, not demonstrated protection against congenital BAV. [21]
Protective genetic or environmental factors None validated for AOVD3. No protective ROBO4 allele, diet, supplement, or exposure has been shown to prevent this Mendelian phenotype. [31][47]
Infection, toxins, radiation, occupation Not demonstrated initiating causes of AOVD3. A 2024 radiation experiment concerned bone-marrow endothelium, not radiation-induced AOVD3. Experimental; PMID:38383474. [77]

Gene–environment interaction: The family study suggests that unidentified genetic and/or environmental influences may affect penetrance, but it did not measure a particular exposure–ROBO4 interaction. A 2024 study shows how inflammation can expose another ROBO4-dependent endothelial response; extrapolating that response to aortic-valve progression remains an inference, not a demonstrated AOVD3 mechanism. Experimental; PMID:38762541. [31][107]

3. Phenotypes

The table separates observed AOVD3-family findings from HPO terms indexed to the condition. Denominators below describe the reported families, not validated disease-wide frequencies. Typical symptom-onset ages, quantitative severity distributions, and phenotype-specific quality-of-life scores have not been established for AOVD3. A congenital valve shape can remain clinically silent until later dysfunction; aneurysm may likewise be detected by imaging before symptoms. Human; PMID:30455415. [31][73]

Phenotype; suggested HPO Type and documented characteristics Reported frequency, course, and functional impact
Aortic-root aneurysm — HP:0002616 Imaging/anatomical sign; arose in 8/8 described affected members of family 1. The paper does not establish an AOVD3-wide onset age or growth rate. [3][158] Four were described as isolated root aneurysms; others had additional ascending-aortic or valve findings. Usually asymptomatic until advanced; surveillance and possible surgery affect daily life. The latter impact is a clinical inference, not an AOVD3 QOL measurement. [3][21]
Ascending tubular-aorta aneurysm — HP:0004970 Imaging/anatomical sign accompanying root and/or valve disease in some family-1 members; severity and progression varied. [3][92] No reliable subtype percentage. Aneurysm carries potential future dissection risk, but the original families do not provide an AOVD3-specific dissection rate. [3][21]
Bicuspid aortic valve — HP:0001647 Congenital anatomical sign; cusp-fusion patterns differed between the families. [3][70] Two family-1 members had reported BAV; the affected son in family 2 had BAV. May be asymptomatic or lead to valve dysfunction and activity limitation. Human; PMID:30455415. [3][31]
Aortic valve stenosis — HP:0001650 Clinical/imaging sign of restricted outflow; reported in both families, with some affected members requiring valve replacement. [3][156] No disease-wide percentage or onset distribution. Severe stenosis may cause exertional limitation, syncope, heart failure, or the need for intervention; these are general stenosis consequences, not individually quantified AOVD3 symptoms. [3][276]
Atrial septal defect — HP:0001631 Congenital structural finding in the mother and son of family 2; ASD subtype not established. [3][162] 2 reported individuals, not a prevalence estimate. Potential effect depends on defect size and shunt; no AOVD3-specific functioning data. [3]
Aortic regurgitation — HP:0001659 Valve functional abnormality reproduced in Robo4-deficient mice; not a well-quantified human AOVD3 phenotype in the original pedigrees. [31][157] Human frequency unknown; avoid transferring mouse penetrance to patients. [31]
Ascending aortic dissection — HP:0004933 Indexed in MedGen’s AOVD3 HPO feature list, but not established as a recurrent event in the original two pedigrees. [73][91][3] A serious potential aneurysm complication; AOVD3 incidence unknown. [21]

Valve thickening/fibroproliferation and medial elastic-fiber abnormalities were pathology findings in studied tissue, not measured population phenotypes. No reproducible AOVD3-specific behavioral, psychiatric, biochemical-laboratory, EQ-5D, SF-36, or PROMIS phenotype has been reported. Human; PMID:30455415. [31]

4. Genetic and molecular information

Gene annotation: ROBO4 (roundabout guidance receptor 4), HGNC:17985, NCBI Gene:54538, OMIM:607528, UniProt:Q8WZ75, chromosome 11q24.2. Its encoded endothelial-associated receptor is the proposed affected protein. The familial findings are germline, not tumor-acquired somatic variants. Human and experimental; PMID:30455415. [61][3][31]

ROBO4 variant reported in the discovery study Evidence and population observation Interpretation for a knowledge base
c.2056+1G>T, splice-donor-site variant, family 1 Eight affected and two apparently unaffected carriers; patient-fibroblast cDNA showed exon-13 skipping and an in-frame transcript lacking 36 intracellular amino acids. Absent from the ExAC dataset used in the study. Human/functional; PMID:30455415. [31] Strongest original segregation-and-splicing example, but evaluate the specific current transcript, ClinVar submission, and gene–disease validity before calling it clinically pathogenic. The +1 position denotes a donor site even though some prose labels it “acceptor.” [31][47]
c.190C>T; p.Arg64Cys, family 2 and an additional proband Affected mother and son; altered endothelial-cell behavior in culture; 19/98,998 ExAC alleles in the original article, approximately 0.00019. Human/in vitro; PMID:30455415. [31][46] Conflicting ClinVar interpretations: one contributing likely-pathogenic submission and one contributing VUS submission; a literature-only pathogenic entry does not resolve the conflict. ClinVar variation 560394 reports gnomAD frequency about 0.00019. Do not silently label this variant definitively pathogenic. [46]
c.283G>A; p.Ala95Thr Rare discovery-cohort proband variant; 5/117,304 ExAC alleles. [31] Candidate association; independent variant-level causation unproven.
c.695C>T; p.Thr232Met Rare discovery-cohort variant; 10/121,068 ExAC alleles. [31] Candidate; not equivalent to a proven AOVD3 diagnosis.
c.1233T>A; p.His411Gln Discovery-cohort variant; absent from the referenced ExAC dataset. [31] Candidate; variant-level pathogenicity unproven.
c.1702C>T; p.Arg568Ter Predicted stop-gain; 12/120,920 ExAC alleles. [31] Predicted truncation, but functional consequence and clinical causation require variant-specific assessment.
c.740T>C; p.Val247Ala Resequencing-cohort variant; 1/121,370 ExAC alleles. [31] Candidate; unproven.
c.839A>C; p.Tyr280Ser Resequencing-cohort variant; 5/117,546 ExAC alleles. [31] Candidate; unproven.
c.1601_1614del; p.Gly534Glufs*49 Predicted frameshift; absent from referenced ExAC dataset. [31] Candidate predicted loss of function; clinical classification needs review.
c.1864G>C; p.Asp622His Reported in two probands; 4/110,004 ExAC alleles. [31] Candidate; recurrence alone does not establish pathogenicity.
c.2245_2246delinsCT; p.Ala749Leu Resequencing-cohort candidate; absent from referenced ExAC dataset. [31] Candidate; unproven.

The study found filtered rare ROBO4 variants in 13/736 probands (1.77%), versus one variant among 376 controls (P=0.0432). That is an enrichment in a selected BAV/ascending-aneurysm cohort, neither AOVD3 prevalence nor the diagnostic yield of ROBO4 testing in an unselected population. Human; PMID:30455415. [3][31]

Updated evidence: In a separate early-complication cohort, ROBO4 had three candidate variants among 63 probands (gene-level comparison P=0.062); variants were not significantly enriched among the 60 BAV-plus-heritable-aortic-disease probands. Human; Musfee et al., 2020, PMID:32748548, https://pubmed.ncbi.nlm.nih.gov/32748548/. A peer-reviewed 2024 exome analysis of 215 early-onset BAV families identified one predicted ROBO4 loss-of-function variant; it did not establish variant-specific AOVD3 penetrance. Human; Mansoorshahi et al., published online September 2, 2024, PMID:39226896, https://pmc.ncbi.nlm.nih.gov/articles/PMC11480851/. [34][301][110][108]

No AOVD3-specific validated modifier gene, epigenetic signature, recurrent chromosomal rearrangement, or somatic mutation was established in these sources. Other BAV-associated genes are important for the differential diagnosis, not automatically genes causing the OMIM-defined ROBO4 subtype. [31][110][21]

5. Environmental information

AOVD3 is not an infectious or zoonotic condition, and no pathogen, toxin, occupational exposure, radiation dose, diet, smoking exposure, or alcohol intake has been demonstrated to initiate the ROBO4-defined disorder. Hypertension and smoking remain clinically actionable general aortic-disease risks; controlling them should not be represented as reversing a congenital valve malformation. The 2022 ACC/AHA aortic guideline recommends treatment of hypertension in patients with thoracic aortic aneurysm and smoking-cessation efforts in those who smoke. [31][21]

6. Mechanism and pathophysiology

Ordered causal chain

  1. Heterozygous ROBO4 sequence variation leads to altered ROBO4 transcript or receptor structure: exon-13 skipping is demonstrated for c.2056+1G>T; p.Arg64Cys changes an extracellular immunoglobulin-like domain. Human; PMID:30455415. [31]
  2. Reduced or altered ROBO4 activity leads to weaker endothelial junctions and barrier function: ROBO4 silencing or mutant expression reduced CDH5/VE-cadherin and TJP1 and increased dextran passage across cultured aortic-endothelial monolayers. In vitro; PMID:30455415. [31]
  3. Barrier disruption leads to a more invasive, mesenchymal-like endothelial state: cultured cells became elongated, expressed more SNAI1 and α-smooth-muscle actin, and invaded more readily. This is evidence suggestive of EndMT, not proof that every human lesion undergoes complete lineage conversion. In vitro; PMID:30455415. [31]
  4. Branch A — developing valve: altered endocardial/endothelial behavior is inferred to lead to abnormal valve formation, including BAV; ROBO4 is expressed in developing mouse endocardial cushions, and deficient mice develop valve anomalies. Direct observation of the entire developmental chain in a human embryo is not available. Experimental plus inference; PMID:30455415. [31]
  5. Branch B — aortic wall: impaired endothelial barrier and mesenchymal-like remodeling are inferred to lead to albumin entry, intimal fibrosis, collagen accumulation, and medial elastin disorganization. These downstream abnormalities were observed in one patient’s aneurysmal tissue; their precise order was not experimentally established in that patient. Human plus inference; PMID:30455415. [31]
  6. Abnormal valve geometry and/or aortic-wall remodeling results in stenosis or other valve dysfunction and aortic-root/ascending-aortic aneurysm; consequent ventricular pressure load or future dissection risk is a clinical extrapolation when applied to an individual AOVD3 carrier. Human/experimental/inference; PMID:30455415. [3][31][21]

Upstream versus downstream. The receptor and endothelial-junction abnormalities are upstream hypotheses; fibroproliferation, elastin damage, altered valve flow, and aneurysm are downstream findings. In the studied aneurysmal aorta, investigators observed diminished endothelial ROBO4 staining, albumin beyond the endothelial surface, collagen-rich intimal/superficial-medial remodeling, and fragmented elastic fibers. These are more direct disease-tissue observations than any proposed named signaling cascade. Human; PMID:30455415. [31]

Mechanistic annotation Supported finding and appropriate ontology suggestion
Cell populations Aortic endothelial cell, CL:0000115, is directly studied; developing valve endocardial/endothelial cells are implicated by mouse expression. Aortic medial smooth-muscle and valve interstitial cells participate in tissue remodeling, but were not proved to be the primary ROBO4-mutant cellular origin. [31][122]
Biological processes GO:0061028, establishment of endothelial barrier; GO:0007155, cell adhesion; GO:0140074, cardiac endothelial-to-mesenchymal transition, as a suggested process annotation, not proof of completed human EndMT. [31][182][185][129]
Cellular components ROBO4-associated plasma membrane, GO:0005886; affected junctions adherens junction, GO:0005912; remodeled extracellular matrix, GO:0031012. These are localization/process suggestions, not demonstrations that the familial variants redistribute ROBO4 to a specific organelle. [31][181]
BMP, NOTCH, TGF-β Original aortic-endothelial experiments found modest reductions in BMP- and NOTCH-responsive markers after ROBO4 silencing, without altered measured TGF-β responses. No single predominant cascade was established for AOVD3. In vitro; PMID:30455415. [31]

Relevant 2024 research, with strict disease boundaries. In irradiated bone-marrow endothelial-cell experiments, ROBO4 depletion augmented endoglin/SMAD, PI3K–AKT–mTOR, and NF-κB-associated responses. Experimental; PMID:38383474, published February 2024, https://pmc.ncbi.nlm.nih.gov/articles/PMC10881562/. These pathways must not be entered as demonstrated AOVD3-valve pathways. In another 2024 study, endothelial ROBO4 promoted TRAF7-associated IQGAP1 ubiquitination, limited prolonged RAC1 signaling and PTGS2/COX-2 expression, and restrained inflammatory permeability. Its human endothelial RNA-seq experiment is deposited as GEO:GSE231460; it did not test AOVD3 valves. Experimental; PMID:38762541, published May 18, 2024, https://pubmed.ncbi.nlm.nih.gov/38762541/. No AOVD3-specific single-cell, spatial-transcriptomic, proteomic, metabolomic, lipidomic, or CRISPR-screen signature was verified. [77][107]

7. Anatomical structures affected

Level Site or cell; suggested ontology Evidence and localization
Primary cardiac Aortic valve, UBERON:0002137 Abnormal leaflet/cusp morphology and sometimes stenosis; left-sided valve, not a bilateral organ. [3][213]
Primary vascular Aortic root, UBERON:0004178; ascending aorta, UBERON:0001496; parent aorta, UBERON:0000947 Root or ascending-aortic aneurysm; the original study examined intima and superficial media. These are anatomically localized lesions, not “left-” versus “right-sided” disease. [3][31][205][200]
Associated cardiac Heart, UBERON:0000948, including the interatrial septum ASD was described in family 2; the left ventricle may be affected secondarily by significant valve dysfunction. [3][221][135]
Tissue and subcellular Endothelium CL:0000115; valve/endocardial tissue; aortic-wall connective tissue, extracellular matrix GO:0031012, plasma membrane GO:0005886 Human tissue and cultured-cell observations support these annotations. There is no demonstrated AOVD3-specific mitochondrial, lysosomal, or ER lesion. [31][122][181]

8. Temporal development

BAV and ASD are congenital structural abnormalities; clinically important stenosis or aneurysm may become evident later. The small published AOVD3 families do not establish a median diagnosis age, annual aortic-growth rate, time to valve replacement, or age-specific penetrance. The practical course is therefore potentially lifelong and variably progressive, rather than a proven fixed-stage syndrome. There is no demonstrated spontaneous remission of a congenital BAV or established aneurysm. Human; PMID:30455415. [3][31]

For context only, a general prospective BAV cohort cited by the aortic guideline had mean ascending-aortic growth of 0.47 mm/year over 4.8 years; those figures cannot be assigned to ROBO4 carriers. The key intervention windows are identification of familial structural disease before complications and surveillance while aortic size, growth, and valve severity still permit planned treatment. [21]

9. Inheritance and population

Characteristic AOVD3-specific conclusion
Inheritance Autosomal dominant pattern proposed in the reported families; HP:0000006 is the relevant inheritance annotation. Human; PMID:30455415. [3][47]
Penetrance and expressivity Incomplete observed penetrance: two apparently unaffected female carriers of the splice variant; manifestations varied between aneurysm, valve disease, and ASD. A numerical lifetime penetrance is unavailable. [3][31]
Anticipation, germline mosaicism, founder effect, consanguinity None demonstrated for AOVD3. [3][31]
AOVD3 prevalence, incidence, carrier frequency Unknown. The discovery study’s 13/736 (1.77%) filtered-variant fraction is not disease prevalence, incidence, or a population carrier estimate. [3][31]
Sex, ancestry, geography Family 1’s 7 affected males and 1 affected female do not establish a population ratio or ancestry-specific rate. No AOVD3 geographic distribution is established. [3]
Broader BAV comparator BAV occurs in approximately 1% of the population and shows about 2:1–3:1 male predominance in the aortic guideline; neither statistic is specific to AOVD3. [21]

10. Diagnostics and screening

Clinical diagnosis starts with anatomy and physiology, not a ROBO4 result. Transthoracic echocardiography (TTE) assesses cusp morphology, stenosis/regurgitation, aortic root and ascending-aortic size, and associated defects. Obtain appropriately gated CT or MRI when echocardiography cannot adequately define the thoracic aorta. ECG, symptom assessment, exercise testing in selected valve patients, and BNP when clinically appropriate address functional impact or intervention timing; none is an AOVD3-specific molecular biomarker. Aneurysmal-tissue histology can reveal remodeling but is not a routine diagnostic biopsy. [21][276][31]

Diagnostic approach Appropriate use and limitation
Family history and examination Obtain multigenerational history of valve disease, thoracic aneurysm/dissection, and unexplained early death; examine for syndromic features suggesting another aortopathy. [21]
Targeted cardiovascular imaging TTE first; CT/MRI if necessary. Screen first-degree relatives of a BAV patient with a dilated root/ascending aorta; screening relatives of a BAV patient without dilation is also considered reasonable. [21]
Multigene sequencing panel For aneurysm/dissection with heritable-aortic-disease risk factors, genetics assessment and an appropriate multigene panel are preferable to assuming ROBO4. Interpret established HTAD genes and BAV candidates according to each gene–disease evidence level. The guideline names ROBO4 among BAV-associated-aortopathy genes, but its confirmed, highly penetrant HTAD-gene list does not include it. [21][47]
Single-gene testing; WES/WGS Family-variant testing can be considered after expert classification of a credible familial variant. WES/WGS may investigate unresolved familial disease, but detection of a rare ROBO4 variant alone is not diagnostic; WES found the original families and a separate candidate in a 2024 cohort. Human; PMIDs:30455415, 39226896. [31][110]
CMA, karyotype, FISH, mitochondrial or repeat-expansion testing Not established routine tests for isolated AOVD3; investigate when a different syndromic or chromosomal diagnosis is suspected. [3][21]
RNA, protein, and other omics Patient-fibroblast cDNA confirmed exon-13 mis-splicing in research. No validated AOVD3 clinical RNA-seq, proteomic, metabolomic, epigenomic, or liquid-biopsy assay was identified. Experimental; PMID:30455415. [31]

Differential diagnosis: other familial BAV etiologies, syndromic or nonsyndromic heritable thoracic-aortic disease, isolated congenital BAV, and acquired calcific or rheumatic valve disease. Phenotype, family history, aortic imaging, and carefully interpreted molecular findings distinguish them; a VUS must not direct cascade testing or aortic surgery. There is no AOVD3 population newborn-screening program. [21][46][47]

11. Outcomes and prognosis

No AOVD3-specific survival curve, five- or ten-year survival percentage, life-expectancy estimate, mortality rate, validated prognostic biomarker, or patient-reported quality-of-life series was found. In the original family 1, three members had undergone aortic valve replacement, demonstrating substantial morbidity in some carriers but not a treatment rate for all AOVD3 patients. Human; PMID:30455415. [3]

Risk assessment must instead use the observed valve and aortic phenotype: severity of stenosis or regurgitation, symptoms and ventricular function, aortic diameter and growth, family dissection history, and relevant coarctation or root phenotype. Even after isolated valve replacement, patients with BAV-related aortopathy can experience later aortic events; lifelong surveillance may be necessary. General BAV outcome statistics are not ROBO4-specific prognostic estimates. [21][276]

12. Treatment and real-world implementation

No drug, gene therapy, RNA therapy, cell therapy, or immunotherapy has been shown to correct the ROBO4 defect or prevent AOVD3 itself. Care follows the measured valve and aortic abnormalities through a cardiology/valve-and-aorta team; the intervention names below are suggested NCIT search labels, not asserted NCIT codes. [21][47]

Intervention; suggested NCIT label Clinical use, outcome, and limitation
Echocardiographic surveillance; “Echocardiography” Track valve function and root/ascending-aortic diameter. With BAV and a root or ascending aorta ≥4.0 cm, guideline-recommended lifelong imaging intervals depend on size and growth, including after valve surgery. [21]
Blood-pressure treatment; “Antihypertensive Therapy” For thoracic aortic aneurysm with average BP ≥130/80 mm Hg, antihypertensive medication is recommended; beta blockers are reasonable to reach BP goals, and an angiotensin-receptor blocker may be an adjunct. No ROBO4 genotype-specific response or pharmacogenomic rule is established. [21]
Valve repair or surgical aortic-valve replacement; “Aortic Valve Repair,” “Aortic Valve Replacement” Consider according to symptomatic severe valve disease, ventricular function, anatomy, and multidisciplinary assessment; three original-family members underwent valve replacement. Surgery treats the lesion without correcting inherited susceptibility. Human; PMID:30455415. [3][276]
Transcatheter aortic-valve intervention; “Transcatheter Aortic Valve Replacement” A possible general severe-stenosis option after shared decision-making; BAV morphology, aortopathy, age, operative risk, and durability matter. It is not an established ROBO4-directed intervention. [271][278]
Aortic-root/ascending-aorta replacement; “Aortic Aneurysm Repair” Under ACC/AHA BAV-aortopathy guidance, recommended at ≥5.5 cm; reasonable at 5.0–5.4 cm plus a dissection risk factor, or ≥4.5 cm when concomitant surgical valve repair/replacement is undertaken at an experienced center. Indexed size and other circumstances can change decisions. These are BAV guidance, not validated ROBO4-specific thresholds. [21]
Genetic counseling and relative assessment; “Genetic Counseling” Explain uncertain penetrance and gene–disease validity; use expert-classified pathogenic/likely pathogenic variants for appropriate cascade testing while retaining clinically indicated imaging of relatives even when testing is negative or uncertain. [21][47][46]
Symptom-directed rehabilitation/support; “Cardiac Rehabilitation” Tailor physical activity and recovery support to valve severity, aortic dimensions, and any intervention. No AOVD3-specific rehabilitative trial, response percentage, or adverse-event rate was established. [21][276]

Surgical and transcatheter procedures have material general risks, including procedural complications and later prosthesis-related follow-up; the reviewed evidence supplies no AOVD3-stratified response or adverse-event rate. No verified AOVD3-specific interventional trial or NCT identifier supports an experimental treatment recommendation. [21][31]

13. Prevention

Primary prevention of an inherited valve malformation is not established. No vaccine or antimicrobial prophylaxis prevents AOVD3, and no proven protective allele or lifestyle regimen prevents transmission or congenital BAV. Genetic counseling can discuss the proposed dominant inheritance and reproductive options without presenting an unvalidated variant as predictive. [3][47][21]

Secondary prevention consists of imaging the affected person and appropriately screening at-risk first-degree relatives, then following valve severity and aortic size. Tertiary prevention consists of BP control, smoking cessation when relevant, planned intervention when guideline criteria are met, and continued post-intervention aortic imaging. There is no AOVD3-specific population or newborn-screening program; this is targeted clinical and family surveillance. [21]

14. Other species and naturally occurring disease

Species; NCBI Taxon Natural disease or ortholog finding Relevance and evidence boundary
Human, Homo sapiens; 9606 Proposed AOVD3 gene ROBO4, NCBI Gene:54538. [61][31] The genetically defined condition in this report.
Dog, Canis lupus familiaris; 9615 Rare naturally occurring BAV has been reported, including a German Shepherd dog and an English Bulldog; canine ROBO4 ortholog NCBI Gene:489306. [245][243][242] No demonstrated canine ROBO4-caused AOVD3 and no validated ROBO4-associated breed/VBO designation. Natural BAV is a comparative phenotype, not proof of the same molecular disease.
Cat, Felis catus; 9685 OMIA lists a natural bicuspid aortic valve entry; feline ROBO4 ortholog NCBI Gene:101084985. [246][242] A phenotype record, not a demonstrated ROBO4 genotype.
Mouse, Mus musculus; 10090 Robo4 ortholog NCBI Gene:74144; experimentally engineered disease models. [241][31] Experimental rather than evidence of a naturally occurring Robo4 breed disease.
Zebrafish, Danio rerio; 7955 robo4 ortholog NCBI Gene:560765; engineered mutant model. [244][31] Valve-flow phenotype supports conservation, but vascular anatomy limits comparison with human ascending aneurysm.

There is no infectious agent, animal-to-human transmission, or zoonotic potential for the genetic AOVD3 hypothesis. [31]

15. Model organisms and experimental systems

Model and resource Manipulation and phenotype recapitulation Limitation or research application
Mouse Robo4 knockout, MGI:1921394; NCBI Gene 74144 Homozygous mice developed variably penetrant valve thickening, BAV or other valve abnormalities, stenosis/regurgitation, and ascending-aortic aneurysm. At 20 weeks, cardiovascular findings occurred in 5/28 males and 2/18 females, versus 0/22 and 0/19 respective wild-type animals. Experimental; PMID:30455415. [31][241] Human original families were heterozygous; a homozygous mouse knockout is not a direct human penetrance model.
Mouse Robo4 exon-13 splice knock-in Engineered c.2089+1G>T produced abnormal exon-13 splicing. At 20 weeks, findings occurred in 1/31 heterozygous males, 4/35 homozygous males, and 0/18 wild-type males. Experimental; PMID:30455415. [31] Closest studied splice-lesion model, but incomplete and genotype-dependent penetrance limits prediction for a human carrier.
Zebrafish robo4 Δ7 frameshift; NCBI Gene 560765 Adult ventriculo-bulbar-valve turbulence/regurgitation was reported in 7/26 heterozygotes and 4/15 homozygotes, versus 4/45 wild types. Experimental; PMID:30455415. [31][244] No overt analogous vascular enlargement; fish anatomy and observation period restrict aneurysm inference.
Cultured human aortic endothelial cells ROBO4 siRNA or expression of familial mutant constructs impaired permeability and junctional markers and promoted mesenchymal-like features. In vitro; PMID:30455415. [31] Tests cellular mechanisms, not whole-valve development, lifetime penetrance, or therapeutic efficacy.
Patient tissue and fibroblast cDNA Aneurysm tissue showed barrier/remodeling abnormalities; fibroblast cDNA established exon-13 mis-splicing. Human tissue/in vitro; PMID:30455415. [31] Tissue came from a limited number of patients; no validated molecular diagnostic or rescue therapy followed.

Knowledge-base conclusion: Record AOVD3 as an autosomal-dominant-pattern, incompletely penetrant ROBO4-associated disease hypothesis with limited curated gene–disease validity. The strongest disease-specific causal path is altered ROBO4 → impaired endothelial barrier/mesenchymal-like behavior → abnormal valve development and aortic-wall remodeling, with the middle cellular steps experimentally supported and several links to the full human phenotype still inferred. Do not import general BAV incidence, prognosis, intervention response, or 2024 non-valvular ROBO4 pathways as if they were measured specifically in AOVD3. [47][31][46][110][107]

Reference Validation

Checked with linkml-reference-validator 0.3.0.

Outcome Count
References checked 27
Resolved 27
Unresolved (possible confabulation) 0
Unverifiable 0
References weighed for topical relevance 27
On topic 15
Off topic 0

All extracted references resolved successfully.

Term Validation

Checked with linkml-term-validator 0.4.5, through the ols: adapter.

Outcome Count
Terms checked 31
Resolved 21
Unresolved (possible confabulation) 0
Obsolete 0
Unverifiable 10

Prefixes with no resolver

Terms carrying these prefixes were not checked either way, because no configured ontology covers them. An unrecognised prefix may name an ontology this run could not reach as easily as one that does not exist, so nothing here is evidence of fabrication: OMIM, Gene, PMIDs, MGI.

21 of 31 terms resolved to a current term; the rest could not be looked up either way.