DDT – Velocardiofacial Syndrome

This summary reviews evidence linking DDT (HGNC:2732) with velocardiofacial syndrome (MONDO_0008644). A case report (PMID:29465581) described a 15‑year‑old patient with hallmark features including immunodeficiency (HP:0002721), velopharyngeal insufficiency (HP:0000220), splenomegaly (HP:0001744), and thrombocytopenia (HP:0001873). Microarray analysis identified a 125 kb deletion at 22q11.23 that encompassed eight candidate genes, including DDT. Despite the deletion involving multiple genes, the loss‐of‑function effect on DDT is consistent with a haploinsufficient mechanism that may contribute to the velocardiofacial phenotype. The reported clinical features and deletion mapping support a potential, though preliminary, association of DDT with the syndrome (PMID:29465581).

While extended segregation data and multiple independent case series are lacking, multi‑patient studies have nominated DDT as one of several candidates contributing to the 22q11 deletion syndrome pathogenesis. Early functional assessment studies suggest that altered DDT expression may disrupt normal developmental pathways relevant to the phenotype; however, more robust experimental replication is needed to establish its role definitively. These integrated findings suggest that, although the current evidence is limited, DDT could be considered in diagnostic evaluations for velocardiofacial syndrome, especially in cases with atypical microdeletions affecting the 22q11 region. Key take‑home: Even preliminary genetic and functional data can provide a rationale for including DDT in clinical assessments of 22q11 deletion syndrome.

References

• Medicine • 2018 • Atypical microdeletion in 22q11 deletion syndrome reveals new candidate causative genes: A case report and literature review PMID:29465581

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