CAJ | 학술논문

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、W403 C/T404S、p.L454P、p.W405X、p.M1I、c.409_c.420de112、c.1176_1178de13、c.1046delG、c.l188delG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MPSⅣA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.
목적 연구중국점다당저적증(MPS)ⅣA형환인반유당알-6-류산염류산지매(GALNS)기인돌변보.방법 대2006-2012년진단위MPSⅣA형적38례환인진행GALNS기인돌변분석；채용불동물충안기산비대、PolyPhen-2연건등험증신착의변이；양수매학급기인분석진행산전진단.결과 (1)38례환인중검출38충GALNS기인돌변(착의돌변점71％),p.M318R위열점돌변(21％),5충돌변(p.P163H、p.G168L、p.A324E、p.L366P급p.F452L)부견우중국환인.발현18충기인신변이:p.E315K、p.G304D、p.R251Q、p.Y240C、p.G161E、p.N32D、p.L390P、p.D60E、p.P420S、W403 C/T404S、p.L454P、p.W405X、p.M1I、c.409_c.420de112、c.1176_1178de13、c.1046delG、c.l188delG급IVS9-2A＞ C; (2) 11개신착의변이위점적안기산위고도혹중도보수안기산；PolyPhen-2연건예측돌변가능영향단백결구급공능,위치병신돌변；(3)위7개환인가정실시료산전진단,3례태인위MPSⅣA형.결론 중국MPSⅣA형환인기인돌변보불동타국,5충돌변부견우중국환인；발현료18충GALNS기인신돌변；중국MPSⅣA형환인기인돌변열점보도불일,수루적경다기인돌변자료급류행병학조사등종합분석.
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),accumulation 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 · mg)] 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-restriction 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 ⅣA.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.M1I,c.409 _ c.420de112,c.1176 _ 1178de13,c.1046delG,e.1188delG and IVS9-2A ＞ C.(2) The polymorphism of novel missense variants were ruled out by the PCRrestriction fragment length polymorphism analysis and no related mutations were found in 50 normal controls.A splice site mutation IVS9-2A ＞ C had been validated by reverse transcription PCR direct sequencing.The amino acid 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 function 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.