激素依赖型肾病综合征患儿NPHS2基因突变

Mutations in NPHS2 Gene in A Child with Steroid-Dependent Nephrotic Syndrome

目的分析中国激素依赖型肾病综合征(SDNS)汉族儿童NPHS2基因突变及其特点。方法分别取1例SDNS患儿及其父母、弟弟(汉族)及50例尿检正常成年人外周静脉血各3mL,枸橼酸钠抗凝,提取基因组DNA。应用PCR方法扩增NPHS2基因的全部8个外显子及其启动子全长,对PCR扩增产物直接进行DNA测序。结果在SDNS患儿NPHS2基因外显子5上检测到1个杂合错义突变-596A>T;在NPHS2基因外显子8上检测到1个杂合同义突变-954T>C。在该患儿NPHS2基因启动子区检测到-116C>T纯合变异,其母亲和弟弟NPHS2基因上也检测到596A>T的杂合错义突变和954T>C杂合同义突变。在其父亲和弟弟NPHS2基因启动子区检测到-116C>T杂合变异。但患儿的父母和弟弟尿检均正常。596A>T为新发现的突变,导致NPHS2基因的编码蛋白podocin的第199位的天冬氨酸(位于stomatin蛋白家族的高度保守区)变为异亮氨酸,即N199I。分析对照人群100条染色体,未发现NPHS2基因596A>T突变;但检测到954T>C同义突变和-116C>T变异。结论汉族肾病综合征患儿对激素依赖可能与NPHS2基因突变有关。

Objective To examine mutations in NPHS2 gene in a Chinese child with steroid -dependent nephrotie syndrome （SDNS）. Methods Peripheral blood samples were collected for genetic analysis from the Chinese child with SDNS, her sibling and parents, and 50 eontrols whose urinalyses were normal. Genomic DNA was isolated from peripheral blood leueoeytes. All 8 exons, exon - intron boundaries and promoter of the NPHS2 gene were amplified by polymerase chain reaction. Mutational analysis of the NPHS2 gene was performed by direct sequencing. Results A heterozygous missense mutation in exon 5 of NPHS2,596A 〉 T,which was novel and leads to an asparagine to isoleueine substitution （N199I） ,was identified in the patient,her sibling and mother,whereas it was not found in 100 chromosomes from 50 controls. A heterozygous silent mutation of 954T 〉 C and a homozygous variant of - 116C 〉 T in promoter of NPHS2 were also detected in the case and her mother. A heterozygous 954T 〉 C and a heterozygous - 116C 〉 T were detected in her sibling,and a heterozygous - 116C 〉 T in her father. In addition,954 T 〉 C and - 116 C 〉 T were also detected in the controls. ConcIusion Nephrotic syndrome may be associated with NPHS2 identified in children.