散发性儿童激素耐药型肾病综合征NPHS2基因突变

Mutations in NPHS2 of sporadic steroid-resistant nephrotic syndrome in Chinese children

目的 分析中国儿童散发性激素耐药型肾病综合征(SRNS)NPHS2基因及其突变特点。方法 研究对象为23例散发性SRNS儿童和53例尿检正常成年人。应用PCR-变性高效液相色谱-DNA序列测定法检测NPHS2基因突变。结果 发现1例患儿为1082T>C突变,该突变引起NPHS2基因编码蛋白podoein第361位亮氨酸变成脯氨酸,而检测对照人群106条染色体,未发现1082T>C。此外,还发现6种NPHS2基因多态性,分别为288C>T、ⅣS3-46C>T、ⅣS3-21C>T、IVS7-74C>G、954T>C和1038A>G。结论 首次证实了中国儿童散发性SRNS存在NPHS2基因突变,其发生率为4.3％(1／23);且1082T>C为新发现的突变,ⅣS3-46C>T和ⅣS3-21C>T为新发现的多态性。

Objective To examine the mutations in NPHS2 gene of sporadic SRNS in Chinese children. Methods Peripheral blood samples were collected for genetic analysis from 23 Chinese children with sporadic SRNS (aged 2. 5 - 14 years). The age of disease onset was (8. 9 ±4. 5) years. Among them, there were 7 patients with renal insufficiency. Fifty-three unrelated adult volunteers whose urianalysis was normal were studied as controls. Genomic DNA was isolated from peripheral blood leucocytes. Eight exons of NPHS2 were amplified by polymerase chain reaction. Mutational analysis was performed by denaturing high-performance liquid chromatography (DHPLC). DNA fragments with aberrant elution profiles revealed by DHPLC were re-amplified and sequenced directly on both strands. Results A heterozygous missense mutation, L361P (1082T > C) that is novel, in exon 8 of NPHS2, was detected in 1 of 23 patients (4. 3% ), whereas it was not found in 106 control chromosomes. Six NPHS2 polymorphisms (288C > T, IVS3-46C > T, IVS3-21C > T, IVS7-74C > G, 954T > C and 1038A > G) were also identified in some of the patients and the controls. Of them, IVS3-46C > T and IVS3-21C > T are novel NPHS2 polymorphisms. There was no significant difference in the genotypic and allelic frequencies of IVS3-46C > T,IVS3-21C > T and IVS7-74C > G between the patients and 53 controls, respectively. Conclusion NPHS2 is also the causative gene in Chinese children with sporadic SRNS. Although this study was limited by the number of patients for analysis, the necessity of genetic examination for mutations in NPHS2 in Chinese children with sporadic SRNS is supported by our investigation.