Main clinical features
• Global developmental delay
• Intellectual disability
• Epileptic encephalopathy (early-onset seizures)
• Microcephaly
• Motor abnormalities
• Hyperactivity or behavioral disturbances
Other observed or postulated features
• Abnormal brain imaging findings (in some patients)
• Variability in severity, possibly depending on variant type (truncating vs missense)
• Electrophysiologic abnormalities on EEG
• In animal models, reduced inhibitory interneuron populations (e.g. parvalbumin interneurons
Prognosis / life expectancy
Because this is a newly characterized condition, robust data on life expectancy are lacking. However, the presence of epileptic encephalopathy and severe neurological impairment suggests that disease is serious and likely lifelong.
