Neonatal Type: Most common presentation. After a few days (rarely more than 48 hours), the
neonate presents with rapidly progressing neurologic symptoms: hypotonia,
apneic attacks, seizures, lethargy, or coma. Seizures range from myoclonic
to grand mal convulsions and are often accompanied by hiccup. A
characteristic burst-suppression pattern is seen on electroencephalogram (EEG) during the first
month and is later replaced by hypsarrhythmia. Death frequently occurs
during infancy or childhood. Survivors have mental retardation, myoclonus,
seizures, and microcephaly.