Tumour necrosis factor-α (-308) gene polymorphism in obstructive sleep apnoea-hypopnoea syndrome

Patients with obstructive sleep apnoea-hypopnoea syndrome (OSAHS) have elevated circulating levels of tumour necrosis factor (TNF)-alpha. The hypothesis in this study was that OSAHS might be associated with the TNF-alpha (-308A) gene polymorphism, which results in increased TNF-alpha production. This hypothesis was examined in OSAHS patients, their siblings and population controls. A total of 206 subjects were recruited. All underwent sleep studies and clinical review, and were subsequently classified as having OSAHS or not depending on apnoea-hypopnoea frequency, sex, age and symptoms. All subjects had blood collected and genotyping was performed on DNA extracted from peripheral leukocytes. Some 192 random UK blood donors were used as population controls. The results demonstrated a significant association for TNF-alpha (-308A) allele carriage with OSAHS (OR=1.8; 95% Confidence interval: 1.18-2.75) when compared with population controls. Siblings with OSAHS were significantly more likely to carry the TNF-alpha (-308A) allele. In addition, 21 pairs of male siblings discordant for carriage of the -308A allele showed a significant level of discordance for the OSAHS phenotype. In conclusion, this study demonstrates an association of tumour necrosis factor-a (-308A) carriage with obstructive sleep apnoea-hypopnoea syndrome, suggesting that inflammation may be implicated in the pathogenesis of this condition.