Discrepancy in the results of Y chromosome microdeletions in an Iranian population

Sir,

A few studies of the Y chromosome microdeletions have been performed among Iranian infertile males. Because of the high frequency of microdeletions of the Y chromosome reported by Malekasgar and Mombaini,[1] we reviewed with a great interest the related paper. They found microdeletions in 51.6% (16/31) of azoospermic patients and 52.6% (10/19) of severe oligozoospermic men in South of Iran.[1] >According to their results, the incidence of Y microdeletions was much higher than the reported frequency in other countries. They reported four azoo/oligozoospermic patients with the deletion of only one of the two markers sY254 or sY255 in these men.[1]

The two markers sY254 and sY255 are specific for the human DAZ genes, which is present in four copies arranged in two clusters, each comprising an inverted pair of DAZ genes.[2] The absence of both STSs indicates the deletion of the entire AZFc region, which removes all copies of the DAZ genes. According to current knowledge, the deletion of only one of these two STSs is impossible and should be always regarded as a methodological mistake. The deletion of individual copies of the DAZ genes is possible but cannot be detected with PCR or multiplex PCR.[3] For the detection of Y chromosome microdeletions in AZFa, AZFb, and AZFc regions, there are validated guidelines endorsed by the European Academy of Andrology (EAA) and the European Molecular Genetics Quality Network (EMQN).[3] This protocol could detect up to 95% of all reported AZF microdeletions;[3] however, Malekasgar and Mombaini did not use this guideline in the screening of infertile men in South of Iran.