A clinical description is given of a syndrome present in three postnatally and two prenatally detected cases with partial trisomy 16p, caused by a familial translocation t(16;21) (p11;q22). The most consistent features of this syndrome are: low birth weight, small head circumference, low-set ears, palato(gnatho)schisis, micrognathia, thumb-agenesis or hypoplasia, hypertonia, overlapping fingers, single umbilical artery, and psychomotor retardation. The clinical picture was identical to that described by Roberts & Duckett (1978) for a single case.