Clinical characteristics and WT1 genetic analysis of patients with steroid-resistant nephrotic syndrome accompanied with genitourinary malformations

目的 分析激素耐药性肾病伴泌尿生殖器异常患儿的临床特点、WT1基因及足细胞分子表达,提高对WT1基因突变在该类疾病的重要致病作用的认识.方法 收集3例激素耐药性肾病伴有或怀疑有泌尿生殖器异常的患儿.采用PCR及RT-PCR的方法分析WT1基因及+KTS(赖氨酸-苏氨酸-丝氨酸)/-KTS比例;采用间接免疫荧光及免疫组化的方法进行足细胞分子(nephrin,pedocin,α-actinin4,WT1及CD2AP)表达.结果 3例患儿发病年龄分别为6个月、1岁及10岁;2例为男性伴泌尿外生殖器异常,1例为男性假两性畸形;临床均表现激素耐药肾病,2例肾脏病理为局灶节段性肾小球硬化.2例检测到删突变,即WT1 IVS 9+5 G＞A和WT1外显子9 1186 G＞A杂合突变.足细胞分子在WT1突变肾组织表达发生改变;1例无WT1表达,1例WT1在足细胞细胞核内的分布与正常对照不同.结论 对于激素耐药性肾病的女性患者或伴有泌尿生殖器异常的男性患者应行染色体核型和WT1基因分析.WT1突变除可能引起+KTS/-KTS比例异常,还伴有足细胞分子表达异常,从而导致蛋白尿的形成和(或)发展.Objective To analyze the clinical features and WT1 gene mutations in patients with steroid-resistant nephrotic syndrome(SRNS)accompanied with genitourinary malformations.The expression of pedocyte molecules wag also investigated in renal specimen of these WT1 mutated patients.Methods From January 2005 to May 2007.3 cages of SRNS accompanied with genitourinary malformations were involved in this study.The expression of pedocyte molecules(nephfin,pedocin,α-acfinin 4,WT1 and CD2AP)in 2 cases was analyzed by immunofluorescence and immunohistochemistry:using PCR to amplify genomic DNA and RT-PCR to amplify WT1 cDNA.GeneScan and GeneScan software were used to quantify the ratio of +KTS/-KTS isoforms.Results The age of onset of the 3 cases were 6 months.1 year and 10years,respectively.The age at diagnosis wag 7 months,9 years and 15 years,respectively.The phenotype of cage 1 and cage 3 wag male accompanied with genitourinary malformations.Case 2 was phenotypic female.Karyotype analysis of the 3 cases revealed 46,XY.Each ca8e wag diagnosed as SRNS.Focal segmental glomerulosclerosis(FSGS)was confirmed in 2 cases.Podocyte molecular expression alfeted in renal tissues of 2 cages.WT1 staining wag negative in cage 1.WT1 expression in case 2 showed a diffuse nuclear staining with less obvious speckles compared with controls.WT1 IVS 9+5 G＞A mutation was detected in case 2 and WT1 exon 9 1186 G＞A mutation wag detected in case 3.No WT1 mutation wag detected in case 1.Conclusions Karyotype analysis and WT1 genetic analyzing should be performed for all female patients with early onset SRNS and in male patients with SRNS accompanied with genitourinary malformations.The abnormal ratio of +KTS/-KTS iseforms caused by WT1 mutations along with abnormal expression of podocyte molecules were involved in the pathogenesis of proteinuria.国家自然科学基金; 北京市自然科学基金; 国家科技支撑计划中文核心期刊要目总览(PKU)中国科技核心期刊(ISTIC)中国科学引文数据库(CSCD)09692-6974