MOLECULAR INVESTIGATION OF 2 MALE-SUBJECTS WITH SHORT STATURE AND A 45,X 46,X,RING(Y) KARYOTYPE/

We studied 2 subjects with a 45,X/46,X,ring(Y) karyotype. Both of them were evaluated because of short stature and a subnormal rate of linea r growth. One patient had additional features of the Ullrich-Turner sy ndrome. Both subjects had normal male external genitalia. Two copies o f the pseudoautosomal gene, MIC2, were present in DNA of each individu al. All sequences examined on the Y-specific portion of the short arm, including those for the sex-determining region Y (SRY) gene, were pre sent. By contrast, portions of the long arm of the Y chromosome were m issing from DNA of both subjects. In subject 1, deletion intervals 6 a nd 7 were missing. In subject 2, deletion interval 5, distal to 5B, wa s missing in addition to intervals 6 and 7. The most likely explanatio n for the ring formation in these subjects is a chromosomal break in t he long arm and in the pseudoautosomal region of the short arm distal to MIC2 with subsequent ligation of the remaining sequences on the lon g arm and short arm. However, a complex rearrangement cannot be exclud ed.