Research On Angiotensin-converting Enzyme (Insert/Deletion) Gene Polymorphism In Children With Primary Nephrotic Syndrome

Objective:To investigate the correlation between angiotensin-converting enzyme(ACE) gene insertion/deletion(I/D) polymorphism and the susceptibility,clinical characteristics and response of treatment of primary nephrotic syndrome in children.Methods:We examined 120 children of the Han nationality including 60 patients with PNS and 60 controls.Salting-out method was used to extract the genomic DNA.Polymerase chain reaction(PCR) technique was performed to identify the ACE(I/D) gene polymorphism in all subjects.Blood pressure,renal function,total cholesterin, triglycerid,uric acid,plasma-albumin,and 24-hours'urinary protein were measured. The treatment response of steriod and progression were recorded.Results:1.The frequencies of the ACD DD genotype and D-allele in PNS patients were 38.3%vs.55.0%,respectively;the corresponding numbers for the control group were 26.7%vs.50.8%.It was similar in patients and control group.2.In the total patient group,SSNS were 45 cases and SRNS were 15 cases.In comparison of the distribution of ACE gene polymorphism and D-allele,there was no difference between SSNS and control group(P=0.757,P= 0.661),but there was significant difference between SRNS and control group(P=0.014,P=0.011),and also between SSNS and SRNS(P=0.021,P=0.006).3.In the total patient group,there were 35 patients with relapse and 25 patients without relapse;8 patients with frequent relapse and 52 patients without frequent relapse.In comparison of the distribution of ACE gene polymorphism and D-allele frequence,there were no significant differences in patients with or without relapse, and also in patients with or without frequent relapse(P＞0.05).4.In patients group,49 patients with clinical type of simpleness and 11 patients of nephritis.In comparison of the distributions of ACE gene polymorphism and D-allele frequence,there was no significant difference in patients with two clinical types (P＞0.05).5.In comparison of the distributions of ACE gene polymorphism and D-allele frequence,there were no significant differences in patients with hypercholesterolemia, patients with both hypercholesterolemia and typertriglyceridemia,and control group (P＞0.05).6.In the patients group,The distribution of ACE gene polymorphism and D-allele frequence were not significantly different in patients with high serum IgE and normal serum IgE(P＞0.05).7.The median age of onset with DD genoype patients was 6.0 years,it was the eldest;the median age of onset withⅡgenotype patients was 2.25 years,it was the youngest.There was significant difference between them(P=0.010).8.The serum creatinine was highest in patients with DD gene type,and lowest in patients withⅡgene type.There was significant difference between them(P=0.024).9.Comparisons of protienuria,plasma-albumin,and uric acid level of different ACE genotypes in patients were not significantly different(P＞0.05).Conclusions:1.Patients with ACE DD genotype may have much higher risk of steroid resistence.2.This study suggests that the D-allele may be a risk factor for PNS combine with renal function injury.3.The age of onset with DD genotype was eldest,and that withⅡgenotype was youngest.The patients with elder age should notice the possibility of steroid-resistant.4.There were no relationships between ACE genotypes polymorphism with susceptibility of PNS,clinical classification,blood fat,protienuria level,plasma-albumin level,uric acid level and relapse or not.