A 45,X male with an X;Y translocation: implications for the mapping of the genes responsible for Turner syndrome and X-linked chondrodysplasia punctata.

In a male patient with a 45,X karyotype, the terminal part of the Y chromosome short arm was translocated as a single block on to the X chromosome. This rearranged X chromosome was, in every regard, the same as that present in XX males resulting from an abnormal X-Y interchange. Correlations between the phenotype of this patient and the extent of the deletions on the X and Y chromosomes allowed us to map the genes responsible for most features of the Turner syndrome between DXS432 and Xqter on the X chromosome, and the homologous Y genes either on Yp in interval 4 or on Yq. The molecular analysis of this X-Y translocation allowed us also to reduce the interval for the X-linked recessive chondrodysplasia punctata gene to a 1.5 Mb interval between DXS432 and DXS31.