Test for Y chromosome microdeletion
The test for detecting Y chromosome microdeletions allows for the evaluation of whether deletion events have removed sequences normally present on the Y chromosome that are involved in regulating spermatogenesis in men.
It consists of screening 24 monomorphic regions of the Y chromosome STS, distributed along the AZFa, AZFb, and AZFc loci of the Y chromosome. The test is able to identify individuals with a microdeletion of one or more genes involved in spermatogenesis, which is therefore responsible for male infertility.
The test also includes the examination of two additional STS regions that serve as internal controls for the system: the SRY region (which allows the diagnosis of males with an XX karyotype) and the ZFX/ZFY region, common to both sex chromosomes, used as a DNA quality control.
Y-MICRODELETION
Available panels
Y chromosome microdeletions
Y-MICRODELETION
Who it's recommended for
The molecular analysis for the detection of Y chromosome microdeletions is performed on blood samples from patients with indications of severe male infertility, due to oligospermia or azoospermia.
The Y chromosome microdeletion test is now included in the diagnostic process for identifying the genetic causes of male infertility, as well as in the preparation protocol for assisted reproduction, since the genetic alteration could be transmitted to male offspring.
Y-MICRODELETION
Analysis method
The Y chromosome microdeletion test is performed by analyzing the DNA extracted from the biological sample under examination.
The analysis protocol involves the use of 4 different fluorescent multiplex PCRs; each multiplex allows the amplification of 6 STS regions plus 2 internal controls: one specific for the SRY region of the Y chromosome (used to diagnose males with an XX karyotype) and one common to both sex chromosomes (ZFX/ZFY). At the end of the amplification, the PCR products are subjected to capillary electrophoresis in an automated sequencer.
The results obtained from each electrophoretic run are subsequently analyzed using a template created with Genotyper® software (Applied Biosystems), which allows for the automatic genotyping of the investigated STS regions and the evaluation of the presence of any deletions.
The absence of one or more peaks, due to the lack of amplification of the corresponding STS region, allows for the diagnosis of a microdeletion, which is highlighted in a summary table that can be used as a report.
The protocol stipulates that each deletion must be confirmed by first amplifying the corresponding region in duplex (along with a previously positive contiguous region) and then in singleplex (as recommended in European guidelines).