Male Endocrine and Genetic Factors · Genetic Causes of Male Infertility
Rocca MS et al., 2023 · The Journal of clinical endocrinology and metabolism
Mutations in the androgen receptor (AR) gene might be associated with infertility mainly because they cause various degrees of androgen insensitivity.
The aim of the study was to evaluate the frequency and type of AR variants in a large cohort of infertile males.
A total of 8224 males of Italian idiopathic infertile couples were referred to the University Hospital of Padova. The main outcome measures were mutational screening of AR, computational, and functional analyses.
We found 131 patients (1.6%) harboring 45 variants in AR gene, of which 18 were novel missense AR variants. Patients with AR gene variants had lower sperm count (P = .048), higher testosterone (T) concentration (P < .0001), and higher androgen sensitivity index (ASI) (luteinizing hormone × T, P < .001) than patients without variants. Statistical analyses found T ≥ 15.38 nmol/L and ASI ≥ 180 IU × nmol/L2 as the threshold values to discriminate with good accuracy patients with AR variants. Patients with oligozoospermia and T ≥ 15.38 nmol/L had a 9-fold increased risk of harboring mutations compared with patients with normal sperm count and T < 15.38 nmol/L (odds ratio 9.29, 95% CI 5.07-17.02). Using computational and functional approaches, we identified 2 novel variants, L595P and L791I, as potentially pathogenic.
This is the largest study screening AR gene variants in men of idiopathic infertile couples. We found that the prevalence of variants increased to 3.4% in oligozoospermic subjects with T ≥ 15.38 nmol/L. Conversely, more than 80% of men with AR gene variants had low sperm count and high T levels. Based on our findings, we suggest AR sequencing as a routine genetic test in cases of idiopathic oligozoospermia with T ≥ 15.38 nmol/L.
Male Endocrine and Genetic Factors · Genetic Causes of Male Infertility
Zuccarello D et al., 2008 · Clinical endocrinology
Mutations in the androgen receptor (AR) gene can cause the androgen insensitivity syndrome (AIS). For complete and severe partial AIS, well-characterized in vitro functional assays can be used for genotype-phenotype correlation; however, for mild forms of AIS, as associated with male infertility, experimental evidence is scarce or lacking. In particular, optimal in vitro functional tests informative about the genotype-phenotype relation have not been described.
The objective of this study was to investigate the association among genotype and phenotype for AR mutations found in infertile males by conventional functional assays and additional in-depth studies performed with several gene reporters.
To this aim, we selected four AR missense mutations associated with isolated male infertility (L547F and two novel mutations A474V and S650G) or partial AIS (Y571H). After introduction of the specific mutations in AR expression plasmid, we performed classical in vitro studies (Western immunoblotting, electrophoretic mobility shift assay, hormone-response curves) and transactivation assays with different reporter constructs (MMTV, Sc-ARU-TK, TAT-GRE- 2X, Slp-ARU-TK and PEM).
Our results showed that standard functional tests provide sufficient information only for severe AR mutations, whereas for AR mutations found in mild AIS patients with male infertility, only an extensive analysis with different in vitro systems, and in particular with PEM promoter, can give information on the functionality of the AR and therefore on the pathogenicity of the mutations and on genotype-phenotype correlation.
Male Endocrine and Genetic Factors · Genetic Causes of Male Infertility
Foresta C et al., 2005 · The Journal of clinical endocrinology and metabolism
Recent reports suggest that children born after intracytoplasmic sperm injection performed for male factor infertility are at increased risk of congenital malformations and chromosome aberrations. To explain these observations, we hypothesized that infertile men may be more likely than fertile men to have genetic abnormalities. We studied 750 severely oligozoospermic men (sperm count <5 million/ml) who were candidates for intracytoplasmic sperm injection, and 303 fertile men. We analyzed the peripheral blood karyotype, the Y chromosome long arm for detection of microdeletions in the azoospermia factors, and mutations in the cystic fibrosis gene and the androgen receptor gene. We also analyzed sperm for chromosome aneuploidies among the 421 men who subsequently entered the in vitro fertilization program. A total of 104 genetic abnormalities were diagnosed, corresponding to a frequency of 13.9% (104 of 750). Chromosomal aberrations were present in 5.6% (42 of 750) of infertile men and 0.3% of controls (one of 295), and they were in most cases alterations of the sex chromosomes. Y chromosome long-arm microdeletions were detected in 6.0% (45 of 750) of infertile men and most frequently included the azoospermia factor c, whereas no cases were found in controls (zero of 210). Mutations in the cystic fibrosis gene were diagnosed in 1.2% (nine of 750) of infertile men and 1.0% of controls (three of 303), and mutations in the androgen receptor gene were found in 1.1% (eight of 750) of infertile men and none of the 188 controls. Sperm sex chromosome aneuploidies were increased in men with karyotype anomalies and Y chromosome microdeletions as well as in subjects without constitutional genetic abnormalities. This study shows that the frequency of genetic alterations is increased among men with severe spermatogenic impairment. Genetic tests and genetic counseling should therefore be considered in oligozoospermic men who are candidates for intracytoplasmic sperm injection.
Male Endocrine and Genetic Factors · Genetic Causes of Male Infertility
Pengo M et al., 2006 · Reproductive biomedicine online
In women, single nucleotide polymorphisms (SNP) of the FSH receptor (FSHR) gene influence FSH concentrations and the sensitivity of the FSHR to FSH in vivo. In contrast, the significance of FSHR R gene SNP in the male is poorly understood. To this aim, the possible role of three FSHR SNP was evaluated in male infertility. SNP in exon 10 (codon 307 and 680) and in the core promoter region (at position -29) of the FSHR gene were analysed by polymerase chain reaction-restriction fragment length polymorphism technique in 150 men representative of the general population, 107 proven fathers, 92 normozoospermic controls, and 215 infertile patients classified according to sperm parameters (38 azoospermia, 53 severe oligozoospermia, 48 moderate oligozoospermia, and 76 slight oligozoospermia). Reproductive hormones were measured in infertile males and normozoospermic controls. No significant difference was found in allelic variants frequency and genotype distribution between each category of subjects when analysing the FSHR exon 10 SNP alone and in combination with the SNP at position -29. Serum FSH concentrations and other andrological parameters did not differ between subjects with different genotype within each group. The data showed that in the Italian population, FSHR genotypes have no influence on FSH concentrations both in normal and infertile males and do not associate with spermatogenetic impairment.
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