Xia-Gibbs syndrome (XGS, OMIM #615829) is a rare neurodevelopmental disorder caused by de novo autosomal dominant nonsense and frameshift variants in the AT-Hook DNA-Binding Motif-Containing 1 (AHDC1) gene, most of which lead to truncated protein synthesis [1, 2]. Here, AHDC1 is linked to AHDC1-related intellectual disability-obstructive sleep apnea-mild dysmorphism syndrome.