HYPK‐Related Neurodevelopmental Syndrome: Case Report of Intellectual Disability, Developmental Delay, and Dysmorphic Features

HYPK is a critical modulator and inhibitor of the NatA complex. Here, we report a male proband with a de novo HYPK variant presenting with developmental delay, autism, and facial dysmorphia. Biochemical analyses show that this pathogenic variant enhances the inhibitory activity of HYPK on NatA‐mediated N‐terminal protein acetylation. Our findings provide the first phenotypic characterization of a pathogenic HYPK variant and elucidate its molecular basis, which will facilitate future diagnosis and management in similar cases worldwide.