The only family known so far to have developed cranio-facial dysostose, has been the object of a new study. Since 1962, 3 new infants affected by this disease were born and another 3 died. The syndrome is characterized by an important growth deficit, small cranium with thin skull bone, a peculiar facies with marked hypoplasia of the middle portion and mandible, multiple and various teeth anomalies. The long bones are short and bent; thickening of the cortex occurred during puberty or in the post-puberal period and seems to increase with age. The mean life-span seems normal. The syndrome is transmitted in an autosomal dominant way with great penetrating force.