Short arm deletion of chromosome 12: report of two new cases.

Two boys (W.M. and C.P.) are described, in each of whom a short-arm deleted C chromosome was apparently present. The clinical findings on W.M. are stenosis of the sagittal sutura associated with atrophy of the nervus opticus and mental retardation, and on C.P. osteogenesis imperfecta. An analysis of the G- and Q-banding patterns revealed in each patient a 12p-- chromosome. The deletion involved most of band p12 as shown by length measurements on G-banded chromosomes. Both cases were compared to proven and presumed cases of 12p-- from literature, but no common clinical phenotype could be demonstrated.