Sperm aneuploidy

Sperm with a high rate of aneuploidy have a negative impact on pregnancy rate and are associated with recurrent pregnancy loss.

Chromosomal abnormalities may be somatic cell in origin, in which case they can be detected by a simple blood karyotype analysis. However, most sperm chromosome anomalies arise as a result of errors during meiosis, which cannot be detected by a blood karyotype analysis. These anomalies can only be detected by looking at the sperm chromosomes directly. Studies have shown that sperm with a high rate of aneuploidy have a negative impact on pregnancy rate and are associated with recurrent pregnancy loss.

This test uses fluorescent in situ hybridisation (FISH) to label individual chromosomes with specific probes. Hundreds of sperm are assessed from one ejaculate. There are limitations to the test as, currently, only 5 probes are used routinely for analysis (three of the 22 autosomes: chromosomes 13, 18 and 21, and the sex chromosomes, X and Y); others are available upon specific request.

The results are reported showing incidence of disomy or nullisomy for each of the autosomes and for both sex chromosomes. A sex chromosome ratio is also reported. It is CE-marked.

 

Instructions for collection of Sperm Aneuploidy specimens

Sperm Aneuploidy testing is not part of the Comprehensive Semen Analysis and needs to be requested as a separate test, test code SPPL. Semen samples ideally need to be frozen as soon as possible after liquefaction, but not longer than 60 minutes post ejaculation. Samples must be cryopreserved in TYB for Sperm Aneuploidy.

If samples are prepared by another laboratory, two cryovials containing not less than 0.25 mls of semen are required. Frozen samples can be sent to TDL, or collected by TDL by arrangement, and must be accompanied with relevant patient details, the sperm count and a GDPR consent form.

A count of a minimum 1 million/ml is required for accurate DNA and aneuploidy reporting.