Single nucleotide polymorphisms of the heat shock protein 90 gene in varicocele-associated infertility.
OBJECTIVE
Varicoceles are associated with impaired testicular function and male infertility, but the molecular mechanisms by which fertility is affected have not been satisfactorily explained. Spermatogenesis might be affected by increased scrotal temperature, such as that caused by varicocele. HSP90 is a molecular chaperone expressed in germ cells and is related to spermatogenesis, motility, and both heat and oxidative stress. Possible correlations between coding single region nucleotide polymorphisms (cSNPs) in the HSP90 gene in patients with varicocele associated with infertility were analyzed, and polymorphisms in these exons were characterized through DNA sequencing.


METHODS
PCR-SSCP and DNA sequencing were used to search for mutations in 18 infertile patients with varicocele, 11 patients with idiopathic infertility and 12 fertile men. DNA was extracted from leucocytes for PCR amplification and SSCP analysis. DNA from samples with an altered band pattern in the SSCP was then sequenced to search for polymorphisms.


RESULTS
Three silent polymorphisms that do not lead to amino acid substitutions were identified.


CONCLUSIONS
Mutations in the HSP90 gene do not appear to be a common cause of male factor infertility. The low incidence of gene variation, or SNPs, in infertile men demonstrates that this gene is highly conserved and thus confirms its key role in spermatogenesis and response to heat stress.
Department of Surgery, Division of Urology, Federal University of Sao Paulo, Sao Paulo, Brazil. pericles.hassun@gmail.com
Pericles A
PA
Hassun Filho
Agnaldo P
AP
Cedenho
Samira B
SB
Lima
Valdemar
V
Ortiz
Miguel
M
Srougi
D018841:HSP90 Heat-Shock Proteins / Q000235:genetics*; D006801:Humans; D007248:Infertility, Male / Q000209:etiology* / Q000235:genetics; D008297:Male; D009154:Mutation / Q000235:genetics*; D016133:Polymerase Chain Reaction; D020641:Polymorphism, Single Nucleotide / Q000235:genetics*; D018807:Polymorphism, Single-Stranded Conformational; D011446:Prospective Studies; D017422:Sequence Analysis, DNA; D012720:Severity of Illness Index; D014646:Varicocele / Q000150:complications* / Q000235:genetics
D018841:HSP90 Heat-Shock Proteins