Lack of association between orexin receptor gene polymorphisms and obstructive sleep apnea syndrome in Japanese

The pathogenesis of obstructive sleep apnea (OSA) is not fully understood, particularly at the genetic level. The orexins have pleiotropic effects on several aspects of the OSA phenotype. The purpose of this study was to investigate the relation between orexin receptor gene polymorphisms and obstructive sleep apnea syndrome (OSAS) in Japanese people. A prospective case-control study was conducted. The study population consisted of one hundred OSAS patients and one hundred control subjects. Nine single-nucleotide polymorphisms (SNPs) in the two orexin receptor genes were genotyped using Applied Biosystems TaqMan SNP Genotyping Assays technology. Both genotypic distribution and allelic frequencies were compared between patients and control subjects. We found that between OSAS patients and control subjects, there were no significant differences in either genotypic distributions or allelic frequencies of the examined SNPs. In conclusion, there are some reports evaluating the plasma level of orexins in patients with OSAS compared to normal subjects. However, the role of orexin genes in the pathogenesis of OSAS has yet to be evaluated. This candidate gene study shows that orexin receptor gene polymorphisms are unlikely to be associated with OSAS in Japanese people.