The correlation between growth hormone receptor (GHR) polymorphism and obstructive sleep apnea syndrome among the Han and Hani population in China

Obstructive sleep apnea syndrome (OSAS) is a common health problem that is associated with abnormality in craniofacial morphology. The growth hormone receptor (GHR) belongs to the cytokine receptor superfamily and mediates the majority of growth hormone signaling, which, among other functions, determines mandibular growth and development. The aim of this study was to determine if correlations exist between single nucleotide polymorphisms (SNPs) in the GHR gene and OSAS in the Han or Hani ethnic groups in China. A total of 274 Han subjects (106 with OSAS and 168 without OSAS) and a total of 270 Hani subjects (64 with OSAS and 206 without OSAS) were enrolled in our study. Genomic DNA was extracted from peripheral blood obtained from all subjects. Genotyping was undertaken for eight SNPs in the GHR gene (rs3756416, rs7727047, rs2910875, rs12153009, rs2972781, rs12518414, rs4410646, and rs6451620) using PCR amplification and Sanger sequencing. The genotype frequency of rs12518414 was associated with OSAS in both the Han and Hani groups, and the A allele frequency was remarkably lower in Hani OSAS patients compared with Hani controls (16.7 vs 29.9%). In addition, the G allele frequency of the rs3756416 SNP was significantly lower in OSAS patients compared with normal controls in the Hani ethnic group (12.5 vs 24.6%). In a comparison between ethnic groups, genotype frequencies of four SNPs (rs2972781, rs6451620, rs12518414, and rs7727047) differed between Han and Hani OSAS patients, with the A allele frequency of the rs12518414 and G allele frequency of the rs7727047 were significantly higher in the Han OSAS patients. In conclusion, significant associations were detected between some SNPs in the GHR gene and OSAS occurrence while others appeared to be ethnicity-dependent.