X-linked sex-determining region Y box 3 (SOX3) gene mutations are uncommon in men with idiopathic oligoazoospermic infertility

Abstract

The X-linked sex-determining region Y box 3 (SOX3) gene is expressed in the developing gonads and brain. Sox3-null mice developed according to genetic sex, but the hemizygous null males were hypogonadal, with extensive Sertoli cell vacuolization, loss of germ cells, and reduced sperm count. We hypothesized that SOX3 mutations might occur in a subset of infertility patients. Genomic DNA samples from 56 infertile men with idiopathic oligo-azoospermia were screened for SOX3 mutations. Three nucleotide substitutions (609 T→C, 732 A→C, and 978 G→A) were identified, none of which altered the amino acid sequence, suggesting that they are polymorphic variants. The 609 T→C substitution was in the HMG box, and the two other substitutions were identified within the polyalanine repeat regions. Three patients had 609 T→C, 2 patients had 609 T→C and 732 A→C, and one had 978 G→A. These data indicate that mutations in the SOX3 gene are not a common cause of male infertility.