Familial encephalopathy with permanent periodic breathing: 4 cases in 2 unrelated families.

In each of 2 unrelated Algerian families, we observed 2 sisters with a severe static encephalopathy which was detected in the first weeks of life. Anoxia at birth occurred in only one case. This previously unreported familial encephalopathy is characterized by severe mental retardation, hypotrophy, abnormal movements with unprovoked startles, major EEG abnormalities with undifferentiated sleep stages and a very particular periodic breathing pattern that persists during waking and sleep. EEG, polygraphic and video recordings were obtained for all patients. The evolution is chronic and stable. There are no major dysmorphic features. No metabolic or anatomic abnormality was found. Gynecotropy is uncertain and the transmission is likely to be recessive.