ADNP syndrome (also known as Helsmoortel-Van der Aa syndrome) is a rare genetic disorder caused by changes in the ADNP gene. This gene plays an important role in the development of the brain and the regulation of many other genes.

Children with ADNP syndrome usually show severe developmental delay, autism spectrum symptoms, pronounced speech disorders and intellectual impairment. Hypotonia (low muscle tone), sleep disorders, cardiac or gastrointestinal problems and typical facial features are also common.

The progression is not progressive, but the symptoms are permanent and require intensive support, therapies and often aids to support everyday life.