Analysis of sex chromosome aneuploidy in sperm from fathers of Turner syndrome patients

Numerical sex chromosome abnormalities were analyzed in sperm from four fat hers of Turner syndrome patients of paternal origin to determine whether th ere was an increased frequency of sex chromosome aneuploidy and to elucidat e whether meiotic malsegregation mechanisms could be involved in the origin of Turner syndrome. Determination of the parental origin of the single X c hromosome (maternal in all four cases) and exclusion of X and Y mosaicism w ere carried out by polymerase chain reaction amplification of five X chromo some polymorphisms and three Y chromosome segments. A total of 45,299 sperm nuclei from Turner fathers and 85,423 sperm nuclei from eight control dono rs was analyzed by three-color fluorescence in situ hybridization. The four patients showed a significant increase in the percentages of XY sperm (mea n 0.22%; range 0.20% to 0.22%) compared with control donors (mean 0.11%; ra nge 0.06% to 0.18%). These results suggest that the four individuals have a n increased frequency of nondisjunctional errors in meiosis I, resulting in the production of an increased proportion of XY spermatozoa and of sperm l acking a sex chromosome.