MOLECULAR-STUDIES OF AN X-Y-TRANSLOCATION CHROMOSOME IN A WOMAN WITH DELETION OF THE PSEUDOAUTOSOMAL REGION BUT NORMAL HEIGHT

A translocation chromosome in a woman with the karyotype 46,X,der(X)t( X;Y) (p22.3; q11.2) was investigated by FISH and STS analysis with mol ecular probes derived from the sex chromosomes. Due to the partial del etion of the short arm pseudoautosomal region (PAR1) from DXYS14 to DX YS147 in the translocation chromosome, the proband is hemizygous for t he gene responsible for growth control (SS) located in this region, ye t does not show growth retardation. Molecular analysis of the Yq arm o f the translocation chromosome revealed the presence of markers DYS273 to DYS246 harboring the hypothesized growth control gene critical reg ion (GCY) on Yq, thereby placing the deletion breakpoint between marke rs DYS11 and DYS273. These results suggest that the Y-specific growth gene GCY on Yq compensates for the missing growth gene SS on Xp22.3.