ApoE genotype and obstructive sleep apnea syndrome

Abstract

The obstructive sleep apnea syndrome (OSAS) is frequently associated with obesity, hypertension, diabetes and dyslipidemia and other cardiovascular risk factors. In addition, patients with untreated of OSAS have an increased cardio-vascular mortality and morbidity Apolipoprotein E (ApoE) plays an important role in the metabolism and transport of lipids. The three main isoforms (E2, E3, and E4) are coded by three common alleles ( ε 2, ε 3, and ε 4), resulting in six main genotypes: ε 2/ ε 2, ε 2/ ε 3, ε 2/ ε 4, ε 3/ ε 3, ε 3/ ε 4, and ε 4/ ε 4. Presence of the APOE ε 4 allele is also associated with HDL (High Density Lipoprotein). The aim of this study was to determine what is in our population the prevalence of different alleles of the ApoE gene, if there is an association of allele ε 4 with OSAS and what is their contribution to metabolic syndrome. Cross-sectional study of 440 men patients. Mean age 54 ± 12 years (range 25–79 years), referred to the sleep unit for study.Written informed consent was obtained from all subjects for the extraction of genetic material, with exclusive analysis of the ApoE gene. Each patient has a clinical history reflecting metabolic and cardiovascular risk and medication in use. nthropometric data were recorded: weight, height, waist circumference and neck circumference. Determination of blood pressure (BP) at baseline. The study protocol included polysomnography (PSG) overnight in our sleep unit. Upon awakening, the BP was measure and simultaneously blood samples were collected, one for biochemical and other for the molecular biology laboratory, in order to extract DNA.The recorded variables were studied with the statistical program Statview. Parametric test was applied ANOVA for quantitative variables and chi-square (X2) for qualitative variables. Accepting a degree of significance of p < 0.05. The distribution of genotypes revealed that the prevalence of the ε 3/ 3 allele was the most predominant (73.6% of cases), followed by the ε 4 allele in 16.4, which is heterozygous in 15.4% ( ε 3/ 4) and 1% homozygous ( ε 4/ 4).The ε 2 allele was the 10% off the population of the study. The ApoE ε 4 patients have more severe OSAS with longer arterial oxygen desaturation during sleep, expressed by the T90. This genotype was associated with a statistically significant increase of inflammation markers and decreased melatonin. Also note that these patients has high tobacco consumption. In our population the distribution of the genotype correlates with is in the literature; there is an evidence of a relationship between ApoE ε 4 genotype with moderate to severe sleep beathing disordered. sleep unit, Hospital General de Castellón.