The Function Of LMX1B Gene Mutation In Steroid Resistant Nephrotic Syndrome Of Early Diagnosis In Children

OBJETIVE Detect the relationship between the SRNS and the normal children, steroid sensitive nephrotic syndrome (SSNS) and steroid resistant nephrotic syndrome (SRNS) in serum of children with LMX1B gene mutation, to investigate the mutation of LMX1B gene in early diagnosis of SRNS value.METHODS collected 200 cases of children’s Morning fasting serum in the First Affiliated Hospital of Guangxi Medical University from January2011 to February 2013, they are including 100 children with SRNS (SRNS group),100 with SSNS (SSNS group),100 normal children as control group, the application of the kit to extract peripheral blood DNA, design LMX1B gene ’s exons 4-6 primers, amplificate them by DNA polymerase chain reaction (PCR), with agarose gel electrophoresis detect the products, single strand conformation polymorphism (SSCP) analyse PCR products, DNA sequencing was performed on the mobility or abnormal strips.RESULTS PCR-SSCP analysis find parts of abnomal single stranded DNA strips, DNA sequencing confirme that the abnormal bands have gene mutations in LMX1B exon4. the 5 and 6 exons found no obvious mutation. Homozygous missense mutation C.744.745 C>A、G>A, R246K (SRNS group five cases, SSNS group and control group all zero case); homozygous missense mutation c.731.733T>C、C>G, G>A, S242R (SRNS group 23 cases, SSNS group 9 cases,2 cases of control group); synonymous mutation c.733G> C, S242S (SRNS group 2 cases,SSNS group 11 cases,3 cases of control group). The comparison between SRNS group and control group、SSNS group and control group, SRNS group and SSNS group:R246k:X2=5.128 P=0.024, the difference was statistically significant between the three groups (P<0.05); S242R:X2=1 8.286 P=0.012, X2=3.463 P=0.063, X2= 7.292 P=0.070, the difference was statistically significant between SRNS group and control group (P<0.05); S242S:X2=0.205 P=0.651 X2=3.763 P=0.052 X2=5.265 P= 0.050, there was no significant difference between the three groups (P≧0.05).CONCLUSION 1.LMX1B gene homozygous missense mutation.C.744.745 C>A、G>A may be the reason of the primary nephrotic syndrome in children with steroid-resistant, and it has some certain value in early diagnosis of children with SRNS。2.LMX1B gene homozygous missense mutation c.731.733 T>C、C>G、G> A, may lead to the incidence of PNS more than the normal children, and more resistant to steroid treatment, the result has not been reported in the literature.3.LMXIB gene mutation c.733 G>C, which encodes a serine, may be a manifestation of gene polymorphism.