Chromosome anomalies and Y chromosome microdeletions as causal factors in male infertility.

Among the 10% or so of men who are diagnosed as oligo- or azoospermic in the absence of any physical obstruction, research is now showing that between 8 and 15% carry a microdeletion in the long arm of the Y chromosome which, by loss of specific DNA segments, leads to loss of vital genes for sperm production. Chromosomal anomalies account for approximately 2% of all men who attend infertility clinics, rising to 15% among those with azoospermia. There are serious implications for couples seeking help by intracytoplasmic sperm injection (ICSI), since chromosomal or gene defects which might normally be lost or eliminated by natural means could be transmitted in offspring. The need for genetic testing of ICSI donors and their offspring is raised, and a requirement for counselling is recommended.