Our findings indicate that there is an association of SNP C677T in the MTHFR gene with male infertility, suggesting that this polymorphism might be a genetic risk factor for male infertility in Chinese men.

Fkbp6 has been proved to be a new component of synaptonemal complexes and be involved in homologous chromosomes pairing and male infertility in mice. To explore the possible association between variations in the FKBP6 gene and impaired spermatogenesis in human, mutation screening of all the eight exons and the intron/exon boundaries of the gene was performed in 323 patients with azoospermia or severe oligozoospermia and 205 fertile controls by denatured HPLC and DNA sequencing. As a result, four novel and one known single nucleotide transitions were identified, including c.58-2AOG, c.111COT, c.156GOT, c.594GOA, and c.216COA (rs3750075). The frequencies of genotype CA, allele A of c.216COA and haplotype 'GAG' consisting of c.156GOT, c.216COA, and c.594GOA were significantly lower in infertile patients than those in controls. These findings suggest that the FKBP6 gene may play a role in modifying the susceptibility to idiopathic spermatogenic impairment in human and propose that the allele A of c.216COA seems to be a protective factor for the development of male infertility.

The presence of gr/gr-DAZ1/DAZ2 deletion in five men with normozoospermia suggests that this deletion per se may not be sufficient for spermatogenic impairment in Chinese men.

No abstract

The H2B family, member W, testis specific (H2BFWT) gene encodes a testis specific histone that plays a crucial role in reorganization and remodeling of chromatin and epigenetic regulation during spermatogenesis, suggesting that the gene may be involved in spermatogenesis impairment. To test the speculation, the allele and haplotype frequencies of two single-nucleotide polymorphism loci in this gene, -9C>T and 368A>G, were investigated in 409 infertile patients with idiopathic azoospermia or oligozoospermia and 209 fertile men as controls using polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) assay. As the results, the frequencies of -9T (52.8% vs. 41.6%, p = 0.009) and 368G (43.0% vs. 32.5%, p = 0.012) were significantly higher in patients than those in controls; after stratifying patients, the significant higher frequencies were still detected in allele -9T for azoospermia (57.4% vs. 41.6%, p = 0.001) and allele 368G for oligozoospermia (45.4% vs. 32.5%, p = 0.007). The haplotype CA was significantly decreased (22.8% vs. 33.0%, p = 0.006) whereas TG was significantly increased (18.3% vs. 7.2%, p < 0.001) in infertile patients compared with controls. These results indicated that the polymorphism -9C>T and 368A>G in H2BFWT gene are associated with male infertility with idiopathic azoospermia or oligozoospermia, suggesting that H2BFWT gene might be contribute to susceptibility to spermatogenesis impairment in Chinese population.