Incidence has been estimated at 1/100 000 births in Japan and 1/50,000 births in the U.K. Approximately 100 cases total have been reported but this may be an underestimate. since OS neonates with early death may escape clinico-EEG diagnosis. Male cases slightly predominate those of females.
Ohtahara syndrome
Pallister–Killian syndrome
Cohen syndrome
Cohen-Gibson syndrome
Berdon syndrome
Scheie syndrome
Gleich's syndrome
Christianson syndrome