FREQUENCY OF Y-CHROMOSOMAL MATERIAL IN MEXICAN PATIENTS WITH ULLRICH-TURNER-SYNDROME

Cytogenetic studies have shown that 40-60% of patients with Ullrich-Tu rner syndrome (UTS) are 45,X, whereas the rest have structural aberrat ions of the X chromosome or mosaicism with a second cell line containi ng a structurally normal or abnormal X or Y chromosome, However, molec ular analysis has demonstrated a higher proportion of mosaicism, and s tudies in different populations have shown an extremely variable frequ ency of Y mosaicism of 0-61%, We used Southern blot analysis and polym erase chain reaction (PCR) to detect the presence of Ycen, ZFY, SRY, a nd Yqh in 50 Mexican patients with UTS and different karyotypes to det ermine the origin of marker chromosomes and the presence of Y sequence s, Our results indicated the origin of the marker chromosome in 1 pati ent and detected the presence of Y sequences in 4 45,X patients, Taken together, we found a 12% incidence of Y sequences in individuals with UTS, The amount of Y-derived material was variable, making the correl ation between phenotype and molecular data difficult. Only 1 patient h ad a gonadoblastoma, We discuss the presence of Y chromosomes or Y seq uences in patients with UTS and compare our frequency with that previo usly reported. (C) 1998 Wiley-Liss, Inc.