Prognostic value of Y deletion analysis - The role of current methods

Y chromosome microdeletions represent the most frequent genetic alteration in azoospermic and severely oligozoospermic men, and screening for microdel etions in AZFa, b and c are routinely performed in the major andrology and infertility centres. Since patients with Y microdeletions often require int racytoplasmic sperm injection (ICSI), the question of whether the type of t he microdeletion present could have prognostic value for the presence of sp ermatozoa in the ejaculate or in the testes [by testicular sperm extraction (TESE)] is an interesting one. The review of the literature on this topic showed that there is still no clear genotype-phenotype relationship, i.e. s imilar testicular alterations may be caused by different types of microdele tions, and apparently identical microdeletions may be associated with diver se tubular damage. Even in azoospermic men, the localization of the microde letion cannot be used as a valid prognostic parameter before TESE-ICSI to i dentify patients with spermatozoa in their testes. The only finding with ab solute negative prognostic value is the presence of complete AZFa-c deletio ns, which are invariably associated with an absence of spermatozoa. Microde letions in AZFa or AZFb seem to have promising prognostic value, but more d ata and gene-specific deletions have to be provided to draw clear conclusio ns. The absence of a clear genotype-phenotype relationship, and therefore o f a prognostic value of Y deletion analysis, is probably due to the current methods used for the screening of the microdeletions. In fact, to date mos t centres do not use gene-specific markers but instead use anonymous primer s that contribute little information to the pathogenic role of the microdel etions.