Partial trisomy 12q: clinical and cytogenetic observations.

High resolution chromosome banding showed a male infant with profound mental retardation, hypertonia and multiple congenital anomalies to have the karyotype 46,XY,-der (2),t(2;12)(q37.3;q24.13)pat. Most of the clinical findings were compatible with those of the previously described cases with partial trisomy 12q. Some of the clinical features seem to disappear with increasing age.