Syndromic Intellectual Disability Caused by a Novel Truncating Variant in AHDC1: A Case Report

Abstract

Mutations in the AHDC1 gene are associated with the Xia-Gibbs syndrome (XGS), a sporadic genetic disorder characterised by developmental delay, intellectual disability, hypotonia, obstructive sleep apnoea, dysmorphic facial features, and cerebral malformations with plagiocephaly. Here we report the case of a 13-year-old Colombian female patient with a history of developmental delay, speech delay, sleep disturbances, and dysmorphic craniofacial features. The whole exome sequencing (WES) test revealed a novel de novo heterozygous frameshift mutation in AHDC1. The present case report describes the second case of mutations in AHDC1 in a Latin American patient. A literature review showed that the clinical features were similar in all reported patients. The WES test enabled the identification of the causality of this disorder characterised by high clinical and genetic heterogeneity.