Low number of Y-chromosome deletions in infertile azoospermic men at a Swedish andrology centre

Recent studies have strongly indicated that at least three regions [azoospe rmia factor (AZF) a-c] on the long arm of the Y-chromosome code for factors involved in spermatogenesis. In order to reveal the prevalence of microdel etions in these regions in a Swedish population, 192 men consecutively refe rred to our andrology unit due to infertility and showing oligozoospermia ( n=53) or azoospermia (n=139) but no obstruction or hormonal disturbances, w ere investigated. For this study we used a multiplex polymerase chain react ion (PCR) method including 13 pairs of primers divided into five different primer mixes. It was found that four men, all with azoospermia, had deletio ns including part of the AZFb region and probably the entire AZFc region. T estis biopsies showed different morphology ranging from absence of germ cel ls to hypospermatogenisis. Of special interest was one patient that was fir st investigated 10 years ago due to primary infertility and oligozoospermia . Today he has developed azoospermia. It is concluded that the number of pa tients with microdeletions on the Y chromosome is rather low (less than 3% in highly selected azoospermic men) in our study compared to a number of ot her studies in which a 1-55% incidence have been reported. It is possible t hat ethnic differences, selection criteria and methodological aspects can c ontribute to the difference between the present and previous studies.