Cytogenetic, molecular and testicular tissue studies in an infertile 45,X male carrying an unbalanced (Y;22) translocation: case report.
BACKGROUND Y-autosome (Y/A) translocations have been reported in association with male infertility. Different hypotheses have been made as to correlations between Y/A translocations and spermatogenetic disturbances. We describe an azoospermic patient with a de-novo Y;14 translocation: 45,X,dic(Y;14)(q12;p11). METHODS AND RESULTS Cytogenetic, fluorescent in-situ hybridization (FISH) and molecular studies have been performed. A 14/22 (D14Z1/D22Z1) centromere and a Y centromere (DYZ1) probe both showed a signal on the translocation chromosome, confirming its dicentricity. Each copy of the translocation chromosome had only one primary constriction, with inactivation of the Y centromere in most (90%) of the cells. The 14 centromere was inactive in the remaining cells (10%). FISH and molecular deletion mapping analysis allowed acute assignment of the Yq breakpoint to the junction of euchromatin and heterochromatin (Yq12), distal to the AZF gene location (Yq11). CONCLUSIONS This study supports the hypothesis that in Y/A translocations infertility might be related to meiotic disturbances with spermatogenetic arrest. In addition, sex chromosome molecular investigations, performed on single spermatids, suggest a highly increased risk of producing chromosomally abnormal embryos.