The familial occurrence and autosomal dominant inheritance of alternating hemiplegia of childhood is reported from Children’s Hospital, and Massachusetts General Hospital, Harvard Medical School, Boston. Hemiplegie attacks without preceding seizure activity occurred in the proband, a 9-year-old, developmentally retarded boy, during the first year of life. Choreo-athetosis and dystonic posturing were noted between attacks. Father, brother, paternal uncle, and paternal grandmother had histories of alternating hemiplegia. Stroke, neurodegenerative disease, and other causes were excluded. The karyotype showed a translocation, 46,XY,t(3;9)(p26;q34) in the patient and affected relatives. Flunarizine decreased attack frequency >70%. 
COMMENT. This is the first description of truly familial alternating hemiplegia, a syndrome of unknown etiology. The authors favor neurovascular or metabolic, rather than epileptic mechanisms.
Sakuragawa N reports 23 cases in an excellent review article from the National Institute of Neuroscience, Ogawa Higashi-cho, Kodaira-shi, Tokyo 187, Japan . The classification of alternating hemiplegia as a migraine variant is discussed.