| domain | syndrome-specific finding | evidence level/limitations |
|---|---|---|
| Disease identity | MONDO:0060713 corresponds to an ultra-rare JAG1-related disorder named **deafness, congenital heart defects, and posterior embryotoxon**; currently linked to **JAG1** in disease-target resources. | High confidence for identifier/target mapping; disease definition is based on a very small historical literature base rather than large registries. (pqac-00000000) |
| Genetic cause | Causal variant reported is **JAG1 p.Cys234Tyr (p.C234Y)**, a missense substitution affecting a conserved cysteine in the first EGF-like repeat. | High confidence from functional/genetic follow-up literature; nucleotide-level HGVS was not available in retrieved context. (pqac-00000002, pqac-00000007) |
| Inheritance / pedigree | The phenotype is described as a **familial, autosomal dominant** disorder segregating in a **nine-member family**. | High confidence for dominant familial segregation and studied family size; exact pedigree structure and penetrance values were not available in retrieved context. (pqac-00000001, pqac-00000007) |
| Defining phenotype triad | Core syndrome-defining features are **deafness + congenital heart defects + posterior embryotoxon**. | High confidence for the triad; retrieved follow-up source does not fully resolve deafness subtype/severity or the full spectrum of cardiac lesions in each relative. (pqac-00000001, pqac-00000007) |
| Liver involvement | In contrast to classic Alagille syndrome, **all nine studied family members had normal liver function**. | High confidence and clinically important distinction; this does not exclude broader JAG1/Alagille overlap in other families. (pqac-00000001, pqac-00000007) |
| Molecular mechanism | p.Cys234Tyr causes **defective post-translational processing**, **lack of cell-surface expression**, **failure to activate Notch signaling**, and is interpreted as causing **JAG1 haploinsufficiency**. | High confidence from functional assays in a later study; mechanism is experimentally supported but was not measured directly in the original family report. (pqac-00000002, pqac-00000003, pqac-00000007) |
| Structural interpretation | The altered cysteine is predicted to disrupt **EGF-repeat folding/disulfide bond formation** in a region crucial for ligand-receptor interaction. | High confidence mechanistic inference supported by conservation/structure discussion; still partly inferential rather than direct structural biophysics for this exact family. (pqac-00000007) |
| Expressivity | The syndrome shows **variable expressivity**, consistent with other familial JAG1 disorders. | Moderate-high confidence; no syndrome-specific quantitative expressivity or penetrance estimates were available. (pqac-00000001, pqac-00000007) |
| Relation to Alagille spectrum | Best interpreted as a **liver-sparing / atypical Alagille-spectrum JAG1 phenotype**, not a wholly separate mechanism. | High confidence from gene-level and clinical-overlap evidence; extrapolation beyond the reported family should be done cautiously. (pqac-00000000, pqac-00000008, pqac-00000010) |
| Broader Alagille context | Broader JAG1-related Alagille syndrome is **autosomal dominant**, often multisystemic, and may occur **without overt liver disease**; JAG1 accounts for most molecularly confirmed ALGS cases. | Useful contextual evidence only; these data are **not syndrome-specific** for MONDO:0060713. (pqac-00000008, pqac-00000009, pqac-00000010, pqac-00000011, pqac-00000012, pqac-00000013) |
| Diagnostics | Current practical diagnosis would rely on **clinical recognition of the triad plus JAG1 sequencing/CNV analysis**, often within broader congenital heart disease or Alagille/ocular-anomaly testing. | Moderate confidence by extrapolation from JAG1/ALGS diagnostic practice; no syndrome-specific diagnostic guideline was found. (pqac-00000009, pqac-00000012, pqac-00000013) |
| Treatment / management | **No syndrome-specific therapy** was identified; management is phenotype-directed (cardiac care, hearing evaluation/habilitation, ophthalmic assessment) with genetics follow-up. | Moderate confidence because absence of evidence reflects rarity; no syndrome-specific interventional studies or trials were found. (pqac-00000008, pqac-00000009) |
| Epidemiology / natural history | **No syndrome-specific prevalence, incidence, or longitudinal natural-history data** were identified. | High confidence for evidence gap; available frequency data pertain to broader Alagille syndrome, not MONDO:0060713 specifically. (pqac-00000008, pqac-00000010) |
| Recent developments (2023-2024) | Recent work mainly strengthens the **broader JAG1/Alagille framework**: alternative diagnoses in Axenfeld-Rieger-spectrum testing (2023) and Jag1-dependent cochlear cell-patterning mechanisms in mouse/scRNA-seq studies (2024). | Indirect but relevant; these studies do not add new syndrome-specific human cases for MONDO:0060713. (pqac-00000005, pqac-00000006) |


*Table: This table summarizes the most defensible syndrome-specific facts for deafness, congenital heart defects, and posterior embryotoxon, while clearly separating direct evidence from broader JAG1/Alagille-spectrum context. It is useful for knowledge-base curation because it highlights what is known with high confidence and where evidence gaps remain.*