A high frequency of Y chromosome deletions in males with nonidiopathic infertility

Microdeletions of the long arm of the human Y chromosome are associated wit h spermatogenic failure and have been used to define three regions of Yq (A ZFa, AZFb, and AZFc) that are recurrently deleted in infertile males. In a blind study we screened 131 infertile males (46 idiopathic and 85 nonidiopa thic) for Y chromosome microdeletions. Nineteen percent of idiopathic males , with an apparently normal 46,XY chromosome complement had microdeletions of either the AZFa, AZFb, or AZFc region. There was no strict correlation b etween the extent or location of the deletion and the phenotype. The AZFb d eletions did not include the active RBM gene. Significantly, a high frequen cy of microdeletions (7%) was found in patients with known causes of infert ility and a 46,XY chromosome complement. These included deletions of the AZ Fb and AZFc regions, with no significant difference in the location or exte nt of the deletion compared with the former group. It is recommended that a ll males with reduced or absence sperm counts seeking assisted reproductive technologies be screened for deletions of the Y chromosome.