Azoospermia associated with a mutation in the ligand-binding domain of an androgen receptor displaying normal ligand binding, but defective trans-activation.
Results suggest that an increase in the number of CAG repeats in the androgen receptor gene to 31 or greater may be associated with the etiology of at least some cases of idiopathic azoospermia.
Androgen receptor (AR) gene mutations have been shown to cause androgen insensitivity syndrome with altered sexual differentiation in XY individuals, ranging from a partial insensitivity with male phenotype and azoospermia to a complete insensitivity with female phenotype and the absence of pubic and axillary sexual hair after puberty.
Deletions in the DAZ (deleted in azoospermia) loci sgamma254 and sgamma255 were found in three patients with idiopathic azoospermia, resulting in an estimated frequency of deletions of 10.7% in idiopathic azoospermia men.
These data, although highly suggestive, do not constitute formal proof that DAZ actually plays a role in azoospermia, as no small intragenic deletions, rearrangements or point mutations in the gene have been found.
The DAZLA (DAZ Like Autosomal) gene on human chromosome 3 shares a high degree of homology with the DAZ (Deleted in AZoospermia) gene family on the Y chromosome, a gene family frequently deleted in males with azoospermia or severe oligospermia.
In men with AZFc subdeltions, loss of two DAZ and one CDY1 gene copy made them highly susceptible to azoospermia and severe oligozoospermia with OR of 29.7 and 26, respectively.
Previous studies have shown that total AR knockout would lead to incomplete spermatogenesis and lowered serum testosterone levels in mice, resulting in azoospermia and infertility.
Blood, spermatozoa or testicular cells from 47 men (27 oligozoospermia, 20 azoospermia), including six Y-deleted patients, were screened for mosaicism using double target fluorescence in-situ hybridization (FISH) with Y centromeric and deleted in azoospermia (DAZ) gene-specific probes.
Copy deletion screening of DAZ gene family on the Y chromosome in 485 patients with idiopathic azoospermia or oligozoospermia and 236 fertile men revealed that the prevalence of deletion patterns of the entire DAZ gene and DAZ1/DAZ2 gene were significantly higher in the patients than in fertile men.
From these, sperm from 40 randomly selected men with no DAZ microdeletions in their leukocytes (n = 10 oligozoospermia; n = 10 asthenozoospermia; n = 10 oligoasthenozoospermia; and n = 10 near-azoospermia) were were compared to sperm from men of normal semen quality (n = 10) using combined primed in situ labelling and fluorescent in situ hybridization (PRINS-FISH) technique as well as screening for sex chromosome aneuploidy.
To investigate the expression of deleted in azoospermia (DAZ), RNA-binding motif (RBM), and chromodomain y1 (CDY1) genes in the testes of men with azoospermia with variable histopathologies.
To assess the contribution of these genetic defects to male infertility, 61 Israeli men with severe oligo- (n = 15) or azoospermia (n = 46), were screened for Y chromosome microdeletions, and the AR-(CAG)n repeat length.
We conclude that partial deletions of the DAZ genes are associated with oligozoospermia but not with azoospermia; however, an increased number of DAZ genes does not seem to be a statistically significant risk factor for spermatogenic failure.