MedGen

A severe deficiency of spermatogenesis. Chromosome Y deletions are a frequent genetic cause of male infertility. The mode of transmission follows a Y-linked pattern, with incomplete penetrance, but as deletions are often associated with infertility, they generally occur de novo. Molecular diagnosis is made by PCR amplification of STS type sequences (sequence-tagged sites) from the AZFa, b, and c regions. All chromosome Y deletions do not necessarily lead to infertility: firstly, some deletions (especially some partial deletions) do not result in spermatogenesis defects; secondly, among men with severe oligospermia, some can father children without infertility treatment. Finally, when mature spermatozoa are found in the sperm or in the testicles, the infertility problem can be solved with medically assisted procreation techniques. However, there is a risk of transmitting the microdeletion to every male infant. [from SNOMEDCT_US]

A rare disorder of sex development (DSD) characterised by histologically confirmed testicular and ovarian tissue in an individual with a 46,XX karyotype. The cause is not elucidated for the majority of cases. A small proportion of individuals have a translocation of a Y chromosome fragment, including the SRY gene, to an X or another chromosome but most individuals (65%) are SRY negative. Some individuals may have a chromosomal mosaicism or a chimerism that results in the presence of Y chromosome containing cells in the gonad. The majority of cases arise as de novo gene variants. [from SNOMEDCT_US]