Partial trisomy 12q24.31----qter.

Clinical details of a male child with the karyotype 46,XY,-4,+der(4),t(4;12) (p16;q24.31)mat are reported and compared with those of other known cases of partial trisomy of the distal region of 12q. This condition is apparently associated with mental and psychomotor retardation, widely spaced eyes, flat nasal bridge, low set ears, down-turned mouth, micrognathia, loose skin at the nape, widely spaced nipples, simian creases, clinodactyly, abnormalities of the genitourinary system, alterations in the sacrococcygeal region, and deformities of the lower limbs. In the majority of the reported cases, the break-point was in the 12q24 region and resulted from adjacent 1 segregation of a maternal balanced translocation.