Eight patients (three sporadic, five from two families) with the velo-cardio-facial syndrome (VCFS) or Shprintzen syndrome are reported. Major clinical findings of this syndrome include a characteristic pattern of facial dysmorphisms, cleft palate, cardio-vascular malformations, and (mostly mild-to-moderate) mental retardation or learning difficulties. The syndrome probably is caused by a dominant gene with very variable expression. From previous reports mostly ascertained from cardio-vascular or cleft palate clinics, the incidence of cleft palate and heart defects was calculated to be 98% and 82%, respectively. Out of eight patients of this study who were diagnosed mainly through their pattern of facial dysmorphisms, only two and four had clefts and heart defects, respectively, further demonstrating the variability in the expression of this gene. Similarly, mental retardation, noted in 100% of previous publications, was not present in all of our patients. In two instances, examination of the mother revealed that she probably carried the mutant gene, but that she showed a milder clinical expression than the index patient. It is suggested that careful family investigations should be performed following detection of an index patient, and that the rate of fresh mutations might be not as high as previously assumed.