ADNP and ADNP-related multiple congenital anomalies - intellectual disability - autism spectrum disorder: In 2014, de novo nonsense or frameshift mutations within the ADNP gene have been found to be cause Helsmoortel-Van der Aa syndrome (HVDAS; OMIM 615873), one of the most frequent forms of syndromic autism comorbid with intellectual disability and several extra-neurological deficiencies accounting for 0.2% of ASD cases worldwide.