MedGen

SETD1B-related neurodevelopmental disorder (SETD1B-NDD) is characterized by developmental delay (mainly affecting speech and language), intellectual disability, seizures, autism spectrum disorder or autism-like behaviors, and additional behavioral concerns. Speech delay and/or language disorder has been reported in most affected individuals. Delay in gross motor skills and mild-to-moderate intellectual disability are common. Most affected individuals have seizures with variable onset and seizure type. Behavioral issues including hyperactivity, aggression, anxiety, and sleep disorders have been reported in approximately half of individuals. Less common features include ophthalmologic manifestations and feeding issues. [from GeneReviews]

Increased frequency of theta wave activity in the electroencephalogram. Theta waves have a frequency of 3.5-7.5 Hertz, and are present in very small amounts in healthy waking adult EEGs. Theta activity is normal in small very amounts in the healthy waking adult EEG in a symmetrical distribution. [from HPO]