Diagnostic testing:
- Healthy male individual with azoospermia or oligozoospermia and/or abnormal sperm morphology/motility
The diagnosis of Y chromosome infertility is suspected in otherwise healthy males with azoospermia or oligozoospermia and/or abnormal sperm morphology/motility for whom other causes of infertility have been excluded (PMID: 20301513). Two to 10% of cases of azoospermia or severe oligozoospermia are associated with microdeletions of the Y-chromosome long arm, at the Azoospermia Factor (AZF) locus. These include AZFa, AZFb (P5/proximal P1), AZFbc (P5/distal P1 or P4/distal P1), and AZFc (b2/b4) deletions, which are detected by PCR amplification of selected regions of the Y chromosome.
This test detects the presence/absence of Y chromosome regions by multiplex PCR amplification of genomic DNA and capillary electrophoresis, as per EAA/EMQN best practice guidelines (PMID: 24357628). Two loci per AZF region are tested: sY84, sY86 (AZFa), sY127, sY134 (AZFb), sY254 and sY255 (AZFc). SRY (sY14) is included as a control for the testis-determining factor on Yp and for the presence of Y-specific sequences when ZFY is absent (e.g. in XX males). Amplification of ZFY / ZFX is used as internal PCR control. The extension of AZFa and AZFb deletions is determined by amplification of additional markers as per EAA/EMQN guidelines.
This test detects complete deletions of the AZFa, b and c regions with a sensitivity of approximately 95% (PMID: 24357628). A negative result does not rule out the possibility that the individual harbors a genetic alteration not included in the assay. Analysis is dependent on accurate clinical diagnosis of affected individuals and on correct reporting of ethnicity and family relationships. DNA variants located in primer binding sites and rare genotyping errors can result in inaccurate diagnosis.
Turnaround time: 2-3 weeks
Specimen accepted:
- 2 x 4 mL blood in EDTA tubes (purple top tube)
- DNA: min 10 ug
- For any other sample type, contact the laboratory for testing availability
Submit your test request using our molecular genetics requisition.