[A case of holoprosencephaly with a flat electroencephalogram].

A case of alobar type of holoprosencephaly, a severe impairment of the development of central nervous system, is presented. This is a case report of 2-month-old boy who had a peculiar physiognomy with a microcephalus and an undeveloped forehead. Echoencephalography showed a defect of almost all cerebellum and a singular ventricle accompanied with severe hydrocephalus. However, his brain stem and cerebellum could be confirmed. His electroencephalogram showed complete flat waves and failed to respond to visual evoked potential test (VEP) and auditory brain stem response test (ABR). Any chromosomal abnormalities were not found.