Clinical Characteristics

Main clinical features

The following clinical features have been observed in patients with CHD5 variants:
•    Mild to severe intellectual disability is observed in the majority of patient. However, patients with normal IQ have also been reported
•    Delayed developmental milestones, with language acquisition more affected than motor development. The first words are pronounced at a median age of 24 months.
•    Behavioral disturbances, including autism spectrum disorder, obsessive-compulsive disorder, self-injurious behaviour, poor eye contact, outburst of anger, and aggressive behaviour
•    Seizures are reported in more than half of the patients. The median age of onset is 10 months, with the earliest onset on day one and the latest at 16 years of age. Severity of the seizures is variable and ranges from generalized tonic-clonic febrile and afebrile seizures to staring spells or myoclonus
•    Hypotonia is the most frequent finding upon neurological examination
•    Facial dysmorphism have been reported but are rather unspecific

Clinical variability
The clinical presentation and severity of CHD5-related disorders is characterized by inter- and intra-familial variability.