We report clinical findings in 2 sisters and 5 sporadic cases with a "new" type of craniosynostosis/craniofacial dysostosis and shortness of stature. Premature closure of lambdoid sutures and posterior part of sagittal suture causes a posteriorly narrow, dolichocephalic skull with small, flat or bulging occiput and protuberance of the forehead; disturbance of the growth of basal skull structures leads to craniofacial dysostosis and (secondary) anomalies of the face. In one patient the coronal suture was also involved. One of the patients had a congenital heart defect. Four untreated patients had mental retardation; 3 had craniosynostectomy with more or less normal psychomotor development afterwards. Some patients had hydrocephalus and 1 had a brain malformation (agenesis of the corpus callosum with presumed interventricular lipoma). The observation of sisters with the same condition suggests autosomal recessive inheritance. This etiologic hypothesis is supported by the fact that 4 of 7 patients are of Spanish, Mexican, or Puerto Rican ancestry; this population probably has a rather high gene frequency and the trait should be relatively common in areas occupied by this population and their descendents. The condition has been designated craniofacial dyssynostosis.