[Partial trisomy 14q II.--Partial trisomy 14q due to a maternal t(12; 14) (q24.4; q21)].

The phenotype of an 18-month-old male infant trisomic for the proximal portion of the long arm of chromosome 14 was reported and compared with that of previously reported cases. For the identification of the resulting syndrome, the most consistent features are psychomotor and growth retardation, and an oval, dysmorphic facies which includes a distinctive form of the mouth and a prominent nose. The trisomy in the child reported here is due to a familial translocation transmitted by the mother and present in at least three generations: t(12;14)(q24.4;q21). The 12q duplication in the child's genome is minimal and does not seem to have contributed to his phenotype.