Pitt-Hopkins syndrome (PTHS ) is a rare genetic disorder caused by a mutation in the TCF4 gene. It is a neurodevelopmental disorder characterized primarily by mental retardation, developmental delays and physical and behavioural abnormalities.

Affected children usually show delayed speech development and motor skills, but often have characteristic facial features that can help with the diagnosis. Common symptoms also include breathing disorders such as hyperventilation and hypoventilation, repetitive movements such as hand flapping, and sometimes epilepsy. Behavioral abnormalities such as anxiety and repetitive behaviors (e.g. repeatedly touching objects) are also common.

The disorder is caused by a change in the TCF4 gene on chromosome 18, and it is usually sporadic, meaning there is no known familial clustering.

There is no cure for Pitt-Hopkins syndrome, but early diagnosis and individual support (e.g. occupational therapy, speech therapy and special support at school) can help to improve the quality of life and promote the development of affected children.