AB26. Y chromosome and male infertility

In infertile couples, a male contribution to infertility is found in 45-50%. The cause of male factor infertility remains largely unexplained, but varicocele and genetic disorder are recognized as major causes leading to spermatogenesis disability. Genetic disorder leads to male infertility include chromosomal abnormalities and Y chromosome microdeletions. Chromosomal abnormalities (numerical or structural abnormalities) can be detected routine karyotype analysis. In non-obstructed azoospemia (NOA) patients, the incidence of chromosomal abnormalities is about 15%, and Europe Association of Urology (EAU) recommend the karyotype analysis in men with azoospermia or oligozoospermia (sperm concentration <10 million/mL). The most common chromosomal aberration causing male infertility is 47, XXY, Klinefelter’s syndrome (KFS). In genetic disorder, dose the extra X chromosome play a most important role? In NOA patients, it’s true. But, in patients with severe oligozoospermia, Y chromosome microdeletions are the most major causes but they cannot be detected by routine karyotyping. Conventional diagnostic testing for the Y chromosome microdeletions is performed by PCR amplification of selected regions of the Y chromosome. Sequence tag site (STS) markers, which are specific for the loci, are amplified and the presence of the PCR products is detected by electrophoresis. Europe Andrology Association showed the guidelines for the diagnostic testing, and recommended six screening markers. In the past, we had used several STS markers including this recommended markers. But, the sensitivity of the recommended markers was insufficient for the Japanese population. To improve the sensitivity and specificity of the testing, we developed a new kit for the detection of molecular Y-chromosome deletions by re-selecting STS markers and carrying out multiplex target detection on the Luminex suspension array platform. In this session, I will introduce this kit in detail.