Y chromosome microdeletion

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Y chromosome microdeletion (YCM) is a family of genetic disorders caused by missing gene(s) in the Y chromosome. Many men with YCM exhibit no symptoms and lead normal lives. However, YCM is also known to be present in a significant number of men with reduced fertility. Men with reduced sperm production (in up to 20% of men with reduced sperm count, some form of YCM has been detected^[1]) varies from oligozoospermia, significant lack of sperm, or azoospermia, complete lack of sperm.

Various genes shown to have some correlation with spermatogenesis in men with reduced fertility include^[2] RBM, DAZ, SPGY, and TSPY.

1 Diagnosis
2 References
3 External links
4 See also

[edit] Diagnosis

Y chromosome microdeletion is currently diagnosed by extracting DNA from leukocytes in a man's blood sample, mixing it with some of the about 300 known genetic markers for sequence-tagged sites (STS) on the Y chromosome, and then using polymerase chain reaction amplification and gel electrophoresis in order to test whether the DNA sequence corresponding to the selected markers is present in the DNA.

Such procedures can test only the integrity of a tiny part of the overall 23 million basepair long Y chromosome, therefore the sensitivity of such tests depends on the choice and number of markers used. Present diagnostic techniques can only discover certain types of deletions and mutations on a chromosome and give therefore no complete picture of genetic causes of infertility. They can only demonstrate the presence of some defects, but not the absence of any possible genetic defect on the chromosome.

[edit] References

^ Krausz, Csilla; Lluis Quintana-Murci and Ken McElreavey (July 2000). "Prognostic value of Y deletion analysis". Human Reproduction 15 (7): 1431-1434.
^ Goncalves, J; Lavinha J. (Apr 1998). "Y chromosome and male infertility" (in Portuguese). Acta Med Port 11 (4): 365-72. PMID: 9644848.