A Clinical Study On The Polymorphism Of Angiotensin Converting Enxyme Genes In Children Patients With Obstructive Sleep Apnea-syndrome

Objective: To study the feature of the polymorphism of angiotensin converting enzyme (ACE) gene insertion/deletion (I/D) and the level of plasma angiotensin â…¡ (Angâ…¡) , endothelin-1 (ET-1) and lipids in children patients with obstructive sleep apnea-syndrome (OSAS) and to discuss their clinical significance.Methods: The genotype was determined by polymerase chain reaction (PCR) in the124 children patients with OSAS and 100 healthy children control. The levels of serum ACE by enzyme kinetics and the lipids by enzyme method or immunoturbidimetric assay were also assessed in the 124 children patients with OSAS and 100 healthy children control; The levels of plasma ET-1 and Angll by radio-immunity assay (RIA) were measured in the 124 children patients with OSAS and 30 healthy children control. To compare the different between the children patients with OSAS and healthy children control.Result: 1. A marked difference in the serum ACE levels was observed among the 3 genotypes (DD, â…¡ and ID). The mean levels of serum ACE in DD genotype class were the highest [DD: (52.1 ± 18.9) U/L, II: (35.5±11.1) U/L, ID: (46.0±15.2) U/L; P<0.01, DD Vs â…¡, P=0.000; ID Vs â…¡, P= 0.007;DD Vs ID, P=0.213]. The mean plasma Angâ…¡ levels in â…¡, ID and DD allele were (81.9±20.4) pg/ml, ( 88.7 ± 32.7) pg/ml and (84.1 ±23.2) pg/ml respectively, with no differences among them. The mean levels of ET-1 and lipids among the ACE genotypes in the OSAS patients have no difference.2. Multifactor linear regression demonstrated that there was no correlation between the polysomngram (PSG) result and the ACE genotypes, the levels of serum ACE, lipids, plasma ET-1 in the children patients with OSAS. There were only positive correlation between the concentration of Angll and the lowest oxygen saturation (SaO₂%) in all the 124 children patients with OSAS. Multifactor linear regressiondemonstrated that there were positive correlations between the concentration of Angll and the age or sex. The ACE genotypes and the levels of the serum ACE did not affect the concentration of plasma Angll.3. The frequency of DD genotype and D allele were significantly higher in the OSAS patients than those in the healthy control (x2=29.701, -ï¿¡=22.611,respectively). There were significantly different in lipids, RBC and MCHC between the 124 children patients with OSAS and the 100 healthy children control. The RBC level was significantly higher and the MCHC level was significantly lower in the OSAS patients than those in the healthy control. Plasma levels of ET-1 and Angll were significantly higher in the 124 children patients with OSAS than those in the 30 healthy children control (/><0.05) .Conclusion: 1. The frequency of DD genotype and D allele were significantlyhigher in the OSAS patients than those in the healthy control. In the DD genotype serum ACE level was greater than it in the ID genotype and II genotype. The polymorphism of angiotensin converting enzyme (ACE) gene insertion/deletion (I/D) ACE genotype may be correlated with OSAS in children patients.2. The ACE genotypes and the levels of the serum ACE did not affect the concentration of plasma Angll. Plasma levels of ET-1 and Angll were significantly higher in the 124 children patients with OSAS than those in the 30 healthy children control. There was no correlation between the PSG result and the ACE genotypes, the levels of serum ACE, lipids, plasma ET-1 in the children patients with OSAS. There were only positive correlation between the concentration of Angll and the lowest oxygen saturation (SaO2%) in all the 124 children patients with OSAS.3. The levels of lipids in OSAS children patients were significantly lower than those in healthy control. The RBC level was significantly higher in the OSAS patients than it in the healthy control. The OSAS children patients may be easy to accompany hypercythemia.