摘要
目的研究中国黏多糖贮积症（MPS）ⅣA型患儿半乳糖胺-6-硫酸盐硫酸酯酶（GALNS）基因突变谱。方法对2006—2012年诊断为MPSIVA型的38例患儿进行GALNS基因突变分析；采用不同物种氨基酸比对、PolyPhen-2软件等验证新错义变异；羊水酶学及基因分析进行产前诊断。结果（1）38例患儿中检出38种GALNS基因突变（错义突变占71％），P．M318R为热点突变（21％），5种突变（P.P163H、P．G168L、P．A324E、P．L366P及P．F452L）仅见于中国患儿。发现18种基因新变异：P．E315K、P．G304D、P．R251Q、P．Y240C、P．G161E、P．N32D、P．L390P、P．D60E、P．P420S、W403C／T404S、P．IA54P、P．W405X、P．M1l、D409-c．420dell2、e1176—1178del3、c．1046delG、c．1188delG及IVS9．2A〉C；（2）11个新错义变异位点的氨基酸为高度或中度保守氨基酸；PolyPhen-2软件预测突变可能影响蛋白结构及功能，为致病新突变；（3）为7个患儿家庭实施了产前诊断，3例胎儿为MPS1VA型。结论中国MPSIVA型患儿基因突变谱不同他国，5种突变仅见于中国患儿；发现了18种GALNS基因新突变；中国MPSIVA型患儿基因突变热点报道不一，需累积更多基因突变资料及流行病学调查等综合分析。
Objective Mucopolysaccharidosis （MPS） type IV A （ MPS IV A ） is an autosomal recessive lysosomal storage disease caused by deficiency of N-acetylgalactosamine-6-sulfate sulfatase （GALNS） needed to degrade glycosaminoglycanes （GAGs）, accmnulation of GAGs in the tissue resulting in disorder of function. So far, the small number of articles about clinical study of Chinese MPS IV A were published and only one paper about gene mutation analysis was published, This study aimed to investigate the mutation spectrum and characteristic of GALNS gene in Chinese patients with MPS IV A who were diagnosed in our hospital. Method Thirty-eight patients from 36 families （ male 17, female 21 ） were diagnosed as MPS IVA by GALNS activity determination [ （0. 85 -＋ 1.33） nmol/（17 h ~ rag） 1 and clinical symptoms during 2006-2012. The average age of diagnosis was （5.7 _＋ 3.6）years. Mutation analysis of GALNS gene performed performed by PCR-direct DNA sequencing for 38 patients. PCR-restfiction fragment length polymorphism analysis was used for validating novel mutation, and also to assess amino acid conservation for novel missense variants in five different species. PolyPhen-2 tool was used to predict the possible impact of missense mutations on the structure and function of the human GALNS protein, etc. Analysis of GALNS activity and gene mutation in amniotic fluid were performed to provide the prenatal diagnosis for some families with MPS type IV A. Result （ 1 ） Thirty-eight kinds of mutation in GALNS gene were identified in 38 patients of them, 71% were missense mutations, p. M318R was a hot-spot mutation （21%） tested. Five kinds of mutation i. e. , p. P163H, p. G168L, p. A324E, p. L366P and p. F452L were only found in Chinese patients with MPS IV A. Eighteen kinds of novel mutation were detected including p. E315K, p. G304D, p. R251Q, p. Y240C, p. G161E, p. N32D, p. L390P, p. D60E, p. P420S, W403C/ T404S, p. L454P, for p. W405X, p. MII, e. 409 _ e. 420del12, e. 1176 _ 1178de13, e. 1046delG, c. 1188delG and IVS9-2A 〉 C. （2） The polymorphism of novel missense variants were ruled out by the PCR- restriction fragment length polymor-phism analysis and no related mutations were found in 50 normal controls. A splice site mutation IVS9-2A 〉 C had been validated by reverse transeription PCR direet sequencing. The amino aeid of mutant position of 10 kinds of missense variants are highly conserved and only p. L454 is moderately conserved position. These missense variants were predicted to cause damage to the structure and funetion of human GALNS protein possibly according to the PolyPhen-2 tool, so these novel missense variants may be disease-causing mutations. （ 3 ） Prenatal diagnosis was provided for 7 families and three fetuses were diagnosed as MPS IVA. Conclusion The GALNS gene mutation spectrum in Chinese patients with MPS IV A is really different from that in other countries, five kinds of mutation were only found in Chinese patients with MPS IV A. The reports of hot-spot mutation in Chinese patients were also different, and should be analyzed by more data of gene mutation analysis and epidemiological study.
出处
《中华儿科杂志》
CAS
CSCD
北大核心
2013年第6期414-419,共6页
Chinese Journal of Pediatrics
基金
上海市科委重大课题（11dz1950300）
“十二五”国家科技支撑计划项目（2012BA109800）
