Cryptorchidism and marker chromosomes: identification of marker chromosomes by fluorescence in situ hybridization.

Identification of marker chromosomes by fluorescence in situ hybridization was performed in 2 cases of cryptorchidism. In case 1, the marker chromosome was derived from chromosome 22. In case 2, the origin of the marker was the centromere of chromosome 8. The extent of the congenital anomalies in these cases was milder than that in cases with complete trisomy of an autosome. These findings suggest that an incomplete extra autosome might influence clinical characteristics.