ADNP and autism spectrum disorder: ADNP syndrome, also known as Helsmoortel-Van der Aa syndrome, is a rare disorder in which sequence variants in the activity-dependent neuroprotective protein (ADNP) gene cause autism spectrum disorder (ASD), intellectual disability, sensory reactivity symptoms, facial dysmorphisms, and an array of other manifestations, including increased risk of seizures, cardiac defects, musculoskeletal issues, and gastrointestinal symptoms [1,2,3,4,5,6,7,8,9,10,11].