Li Jian-guo, Zhao Dan, Ding Jie, Xiao Hui-jie, Fan Qing-feng, Guan Na, Chen Yan, Zhang Hong-wen
Department of Pediatrics, Peking University First Hospital, Beijing 100034, China.
Zhonghua Er Ke Za Zhi. 2008 Sep;46(9):692-7.
To analyze the clinical features and WT1 gene mutations in patients with steroid-resistant nephrotic syndrome (SRNS) accompanied with genitourinary malformations. The expression of podocyte molecules was also investigated in renal specimen of these WT1 mutated patients.
From January 2005 to May 2007, 3 cases of SRNS accompanied with genitourinary malformations were involved in this study. The expression of podocyte molecules (nephrin, podocin, alpha-actinin 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.
The age of onset of the 3 cases were 6 months, 1 year and 10 years, respectively. The age at diagnosis was 7 months, 9 years and 15 years, respectively. The phenotype of case 1 and case 3 was male accompanied with genitourinary malformations. Case 2 was phenotypic female. Karyotype analysis of the 3 cases revealed 46, XY. Each case was diagnosed as SRNS. Focal segmental glomerulosclerosis (FSGS) was confirmed in 2 cases. Podocyte molecular expression altered in renal tissues of 2 cases. WT1 staining was negative in case 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 was detected in case 3. No WT1 mutation was detected in case 1.
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 isoforms caused by WT1 mutations along with abnormal expression of podocyte molecules were involved in the pathogenesis of proteinuria.
分析伴有泌尿生殖系统畸形的激素抵抗型肾病综合征（SRNS）患者的临床特征及WT1基因突变情况。同时，对这些WT1基因突变患者的肾组织标本中足细胞分子的表达进行研究。
2005年1月至2007年5月，本研究纳入3例伴有泌尿生殖系统畸形的SRNS患者。对其中2例患者的肾组织进行免疫荧光和免疫组化分析，检测足细胞分子（nephrin、podocin、α -辅肌动蛋白4、WT1和CD2AP）的表达；采用聚合酶链反应（PCR）扩增基因组DNA，逆转录聚合酶链反应（RT-PCR）扩增WT1互补DNA（cDNA）。使用基因扫描（GeneScan）及相关软件定量分析+KTS/-KTS异构体的比例。
3例患者的发病年龄分别为6个月、1岁和10岁，诊断年龄分别为7个月、9岁和15岁。病例1和病例3为男性，伴有泌尿生殖系统畸形，病例2为表型女性。3例患者的核型分析均显示为46, XY。3例均诊断为SRNS，其中2例确诊为局灶节段性肾小球硬化（FSGS）。2例患者肾组织中的足细胞分子表达发生改变。病例1中WT1染色呈阴性。病例2中WT1表达显示弥漫性核染色，与对照组相比斑点不太明显。病例2检测到WT1第9内含子+5 G>A突变，病例3检测到WT1第9外显子1186 G>A突变，病例1未检测到WT1突变。
对于所有早发性SRNS女性患者及伴有泌尿生殖系统畸形的SRNS男性患者，均应进行核型分析及WT1基因分析。WT1基因突变导致的+KTS/-KTS异构体比例异常以及足细胞分子表达异常参与了蛋白尿的发病机制。
