Novel mutation identified in causes IDDSADF: a case report and literature review.

The carbon catabolite repression 4-negative on TATA-less transcription complex subunit 3 gene () plays a key role in regulating the mRNA transcription and protein translation of other genes. Mutations in have also recently been implicated as a causative factor of intellectual developmental disorder with speech delay, autism, and dysmorphic facies (IDDSADF). However, to date, only a few mutations have been reported to be associated with IDDSADF-related diseases. In the present case, we report a Chinese patient with developmental delay, verbal regression, and facial dysmorphism, in whom cerebral magnetic resonance imaging showed an expansion of the lateral ventricle. The patient was diagnosed with an IDDSADF-related disease caused by a c.1616_1623del mutation in exon 14 of , which was confirmed by whole-exome sequencing and direct Sanger sequencing. This case report is the first known documentation of a pathogenic mutation at the c.1616_1623del locus of in the worldwide population. It provides a critical theoretical basis for the specific gene-based diagnosis of IDDSADF-related diseases and expands the mutation profile of .