A daughter and two sons of possibly consangineous parents died after motor and mental deterioration at 18, 16 and 15 months of age. Spongy degeneration of the CNS (Canavan-van-Bogaert-Bertrand type) was diagnosed on neuropathological examinationtion; the histological findings were almost identical in the patients. Own clinical experiences are compared with reports from the literature; data important in clinical and differential diagnosis are reviewed. Pathogenetical and etiological aspects are discussed; autosomal recessive inheritance has to be considered in genetic counselling.