AHDC1 and AHDC1-related intellectual disability-obstructive sleep apnea-mild dysmorphism syndrome: Additionally, the first reports of Xia-Gibbs syndrome, caused by a heterozygous mutation in the AHDC1 gene, involved children with corpus callosum hypoplasia, intellectual disability, delayed development, failure to thrive, hypotonia, esotropia, dysmorphic features, including low-set ears and flat nasal bridge, and obstructive sleep apnea [12].