Confirmation of trisomy 22 in two cases using chromosome painting: comparison with t(11;22).

We present a nonmosaic case of trisomy 22 in a liveborn, abnormal infant and a second case of a fetus who died in utero. Both have been verified cytogenetically and confirmed by in situ hybridisation with a centromeric alphoid probe and chromosome painting. The accuracy of the combined cytogenetic and molecular cytogenetic approaches in the karyotype determination is highlighted by comparison with a case showing partial translocation of chromosome 22 in t(11;22) (q23;q11).