New gene linked to male infertility

1. Mutations in TEX11 were found in 2.4% of infertile men with non-obstructive azoospermia without another known cause.

Evidence Rating Level: 3 (Average)

Study Rundown: Azoospermia refers to the absence of sperm cells in the semen. This may be due to an obstruction, or an inability to produce mature sperm cells (non-obstructive azoospermia). While some chromosomal abnormalities have been associated with subtypes of non-obstructive azoopermia, the genetic basis of the majority of patients affected is not fully understood.

The authors of this study applied various molecular techniques to identify mutations in the gene TEX11 as a cause of non-obstructive azoospermia. TEX11 gene mutations were found in 2.4% of men in this study who had non-obstructive azoospermia without another known cause. The study results indicate that TEX11 mutations may be a newly found genetic cause of non-obstructive azoospermia in European men. More genetic causes remain to be found.

Click to read the study, published today in NEJM

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In-Depth [case-control study]: The authors first performed array comparative genome hybridization (aCGH) using the DNA of 15 American men with idiopathic non-obstructive azoospermia. One of the patients had a 90kb deletion in the X-linked gene TEX11, which is involved in chromosomal crossover in meiosis. TEX11 mutations are known to cause meiotic arrest in mice when deleted.

The authors then sequenced TEX11 in 48 additional men with azoospermia, and found two more patients with TEX11 mutations. A replication study was performed in 240 German men with azoospermia. Four were found to have TEX11 mutations. Out of the seven patients with TEX11 mutations, 5 had azoospermia with meiotic arrest and 2 had mixed testicular atrophy. Immunohistochemistry showed that TEX11 expression was germ cell specific.

Image: PD

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