Polymorphism of the ACE Gene and the Risk of Obstructive Sleep Apnoea

Introduction: Obstructive sleep apnoea/hypopnea syndrome (OSA) is characterized by obstruction of the upper airway during sleep, resulting in repetitive breathing pauses accompanied by oxygen desaturation and arousal from sleep. Among the candidate genes affecting the risk of OSA, genes whose polymorphisms influence the development of diseases with similar pathogenesis such as OSA could be listed: APOE, genes for leptin and leptin receptor, TNFA1, ADRB2 and ACE (gene for angiotensin-converting enzyme). Until now there has been a confirmed relationship between ACE gene polymorphism and cardiovascular diseases, but its effect on the incidence of OSA is debatable. The aim of this study was to investigate the effect of ACE gene insertion/deletion (I/D) polymorphism on the risk of OSA. Material and methods: Fifty-five patients with confirmed diagnose of OSA and qualified to CPAP therapy entered the study. The control group included 50 subjects who did not complain of any sleep related symptoms. Diagnose of OSA was set on the basis of full overnight polysomnography together with Epworth Sleepiness Scale according to American Academy of Sleep Medicine guidelines. DNA was isolated from peripheral blood leukocytes with Qiagen DNA mini Kit. ACE gene polymorphism was determined in genomic DNA using allele specific polymerase chain reaction. Different sizes of PCR products were observed on agarose gel electrophoresis. Results: There were non-significant differences in the frequency of ACE genotypes. However, allele D had significantly lower prevalence in the study group than in the control group. (χ² = 4.25 p = 0.04). Moreover, I allele carriers had a threefold greater risk of developing OSA (HR = 2.748, 95% CI = 1.029–7.340, p < 0.05). Conclusions: Analysis of ACE gene polymorphism might be useful to determine the risk of developing OSA in clinically predisposed patients.