OBJECTIVETo study the correlation of nucleotide polymorphism in the ubiquitin-specific protease 26 (Usp26) gene with idiopathic male infertility and its action mechanism in spermatogenesis.

METHODSBased on the WHO criteria (4th ed.), we selected 41 patients with idiopathic infertility from 150 infertile males, and enlisted 50 normal fertile men as controls. We examined the selected patients for mutations using polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) analysis, and determined how and where the mutations occurred by gene sequencing.

RESULTSLow sperm concentration and poor sperm motility were found in the 41 men with idiopathic infertility. Nine (22.0%) of them exhibited changes in the Usp26 gene (P = 0.01), including compound mutations of 364insACA and 460G > A in 8 (19.5%, P = 0.01) and 1 044T > A substitution in 1 (2.4%, P > 0.05). The above three variations led to changes in the coding amino acids. No other changes were found in the remaining patients and normal fertile controls.

CONCLUSIONThe nucleotide polymorphisms of the Usp26 gene might be closely related with idiopathic male infertility, and exert negative effect on the testis function.