黏多糖贮积症Ⅱ型一家系IDS基因分析及产前诊断

目的 确定黏多糖贮积症Ⅱ型(Mucopolysaccharidosis type Ⅱ,MPS Ⅱ)一家系的致病基因突变,并对高危胎儿进行产前诊断.方法 应用聚合酶链反应和直接测序的方法,对先证者、胎儿及部分家系成员艾杜糖-2-硫酸酯酶(iduronate-2-sulfatase,IDS)基因的所有外显子及其与内含子交界处序列进行检测;对测序发现的性质未知的碱基改变采用高效液相色谱技术(denatruring high-performance liquid chromatography,DHPLC)在正常人群中进行筛查.结果 检测到先证者IDS基因3个碱基改变:5号外显子c.684A>G,6号外显子c.851C>T,7号外显子c.892C>T;先证者母亲和外祖母的IDS基因存在c.684A>G杂合改变,c.851C>T杂合改变及c.892C>T杂合改变;100例家系外正常男性未发现IDS基因5号外显子c.684A>G和6号外显子c.851C>T的碱基改变;胎儿基因型与先证者相同.结论 IDS基因c.892C>T突变是该MPS Ⅱ患者的主要致病原因;产前诊断证明胎儿为男性患病胎儿.     

黏多糖贮积症Ⅲ型的鉴别诊断与产前诊断

目的 建立以人工合成荧光底物测定乙酰肝素N-硫酸酯酶(SGSH),α-N-乙酰葡萄糖苷酶(NAGLU)活性的方法,应用这两种方法对黏多糖贮积症Ⅲ型中的A、B亚型(MPSⅢA和ⅢB)病例进行鉴别诊断,并对MPSⅢB高危妊娠的孕妇进行了产前诊断,同时从分子遗传学方面对MPSⅢA患儿进行了SGSH基因分析.方法 采用人工合成的荧光底物(4-甲基伞形酮-α-D-N-硫酸葡萄糖苷4-methylumbelliferyl-α-D-N-sulphoglucosaminide.Na,4-甲基伞形酮-N-乙酰-α-葡萄糖苷4-methylumbelliferyl-α-N-acetylglucosaminide)测定疑似患儿白细胞和血浆中SGSH及NAGLU活性,在收集的12例患儿中,女4例,男8例,年龄3~10岁.来自10个无相关的家庭.用MPSⅢA的患儿外周血白细胞DNA进行SGSH基因的外显子PCR扩增,并通过的序列测定确定突变位置.用绒毛或经培养的羊水细胞为检材,对MPSⅢB高危妊娠的孕妇进行产前诊断.结果 获得中国正常人白细胞中SGSH活性正常值4.4～8.1 nmot/(17 h·mg蛋白),各种组织中NAGLU活性正常值:血浆中为33.3～62.4 nmoL/(4 h·ml),绒毛组织为44.9~91.7 nmol/(17 h ·mg蛋白),经培养的羊水细胞为53.2-82.2 nmol/(17 h·mg蛋白);在12例疑似患儿中确诊了7例MPSⅢA(其中两例为同胞),5例MPS ⅢB患者(其中2例为同胞),SGSH基因分析发现6种突变类型,已知突变5种(G191R,D235N,R377C,E447K和R233X),插入突变1种(D219Wfs264X),此插入突变为新生突变.3例MPSⅢB产前诊断中,2例胎儿正常,1例胎儿受累.结论 应用荧光法测定SGSH和NAGLU酶活性是敏感、可靠、快速的方法,可用于MPSⅢA和ⅢB病例的鉴别诊断及产前诊断;SGSH基因分析方法成本低,突变检出率高,可用于MPSⅢA的诊断和产前诊断.     

IDS 基因同义突变致黏多糖贮积症Ⅱ型一家系报告

目的探讨黏多糖贮积症Ⅱ型(MPSⅡ)的临床表现及基因变异。方法分析1例MPSⅡ先证者及其家系成员的临床资料、基因检测及艾杜糖-2-硫酸酯酶活性检测结果。结果先证者,男,15岁,体格发育障碍、听力下降。影像学示脑室系统扩大,椎骨、肋骨等骨发育不良。尿黏多糖阳性。IDS的8号外显子同义突变(c.1122CT)。先证者及其母亲的艾杜糖-2-硫酸酯酶活性分别为0、6.96 nmol/(4h·mg)。诊断为MPSⅡ。家系中有6例患者及1例疑似者,全为男性,除先证者外,还有1例存活,其余4例夭折。1例疑似者于孕7月余时产前诊断脑积水终止妊娠。检测到5例女性携带者。结论先证者经艾杜糖-2-硫酸酯酶活性检测和基因检测确诊为MPSⅡ,发现多名女性致病基因携带者及男性患者。     

黏多糖贮积症Ⅱ型分子遗传学研究进展

黏多糖贮积症Ⅱ型是罕见的单基因遗传疾病.以往研究集中于对发现的散在突变作热点突变区域分析.近年来,随着更多新突变的发现,探讨基因突变如何影响剪切,使该疾病基因型与表型的联系成为该领域研究难点和热点.该文从分子遗传学角度,对该病的致病基因IDS的基本特点、基因突变、女性患者基因突变分析、基因型与表型关系研究及进展作概述.研究发现,在今后对该疾病的基因检测应考虑基因-假基因重组的可能性,尽可能从cDNA水平研究突变对剪切的影响,从而更有助于理解基因型与表型的关系.     

黏多糖贮积症47例的常见酶学分型

目的 对临床疑似黏多糖贮积症患儿进行常见酶学分型.方法 收集70例临床疑似黏多糖贮积症的患儿,临床疑似黏多糖贮积症的指征包括:生长落后,丑陋面容,骨骼畸形,肝脾增大,智力落后,关节僵硬/松弛等.收集疑似黏多糖贮积症患儿外周血,分离白细胞后,用人工荧光底物法和生物化学方法,分别检测导致Ⅰ,Ⅱ,ⅣA,ⅣB,Ⅵ及Ⅶ缺陷的酶,α-L-艾杜糖酶,艾杜糖醛酸硫酸酯酶,半乳糖胺-6-硫酸硫酸酯酶,β-半乳糖苷酶,芳基硫酸酶酶B及β葡萄糖醛酸酶的活性.结果 在70例可疑患儿中,共确诊黏多糖贮积症47例,其中Ⅰ型7例(占确诊黏多糖贮积症例数的15%),Ⅱ型28例(59%),ⅣA型12例(26%),未发现ⅣB,Ⅵ及Ⅶ型的患儿.黏多糖贮积症Ⅱ型患儿临床表型多样,ⅣA型患儿中67%有典型的关节松弛表现.结论 Ⅱ型可能是中国人黏多糖贮积症中最主要的一型,其他较常见的是ⅣA型和Ⅰ型.     

粘多糖贮积症Ⅱ型IDS基因的1343-TT新突变

目的研究中国粘多糖贮积症Ⅱ型（MPSⅡ）艾杜糖-2-硫酸酯酶（IDS）的基因突变,为产前基因诊断打下基础。方法应用尿粘多糖含量检测、聚合酶链反应．变性高效液相色谱（PCR-DHPLC）对1例MPSⅡ患儿及其父母的IDS基因的突变热点exons9,3,8,进行突变检测,并对PCR-DHPLC检出的突变样品进行直接测序。结果经PCR-DHPLC分析,发现患儿的IDS基因exon9有明显异常峰形;DNA序列分析进一步发现,患儿IDS基因的exon9发生1343-TT新移码突变,突变部位在第407位密码子（TTT）内,即IDS基因cDNA第1343bp的T后缺失了2个T,并在第429位提前遇上终止密码TGA,导致肽链从550个氨基酸缩短至428个。患儿为这一突变的半合子,而其母为这一突变的杂合子。结论新发现的移码突变（1343-TT）导致肽链比正常的少了122个氨基酸,极可能引起酶活性大大降低,因此可能是该MPSⅡ患儿发病的真正原因。     

黏多糖贮积症Ⅰ型二例基因突变检测及产前诊断

目的 对黏多糖贮积症Ⅰ型病例进行基因检测,对再孕母亲进行产前诊断.方法 用酶学检测方法 确诊2例黏多糖贮积症Ⅰ型先证者;采用PCR扩增技术结合序列分析的方法,检测2例先证者血液及其再孕母亲羊水细胞中IDUA基因外显子及其两侧内含子.结果 在2例经酶学检测确诊的先证者中共检测出4种基因突变:p.L238R、c.883InsC、c.531InsT、p.L346R,2种为插入突变,2种为错义突变.在先证者1母亲羊水细胞IDUA基因中未发现致病基因突变,羊水细胞中IDUA酶活性为9.0 nmol/(h·mg蛋白);在先证者2母亲羊水细胞IDUA基因中检测到与先证者相同的两个致病突变,羊水细胞中IDUA酶活性为0.5 mol/(h·mg蛋白).结论 从黏多糖贮积症Ⅰ型先证者发现的4种突变中,p.L346R为已知突变,p.L238R,c.883InsC,c.531InsT为首次发现的新突变.胎儿1未获得与先证者相同致病基因,为正常胎儿.胎儿2获得与先证者相同致病基因,为受累胎儿.产前基因诊断结果 与酶学产前诊断结果 相符合.

Abstract：

Objectiye Mucopolysaccharidosis type Ⅰ(MPS Ⅰ; MIM# 252800)is an autosomal recessive disease that results from the deficiency in the lysosomal enzyme α-L-iduronidase(IDUA).IDUA is one of the enzymes involved in degradation of glycosaminoglycans heparan sulphate and dermatan sulphate.The deficiency of IDUA leads to widespread accumulation of partially degraded mucopolysaccharides inside lysosomes,resulting in progressive cellular and multiorgan dysfunction. Up to now there is no definitely effective treatment for this disorder,therefore it is important to provide an accurate genetic diagnosis and prenatal diagnosis for the MPS Ⅰ families.This study was conducted to detect IDUA gene mutation in patients with MPS Ⅰ and make a definite diagnosis of homozygote or heterozygote and make first trimester prenatal diagnosis.Method The 2 male probands included in this study were diagnosed as MPS Ⅰ patients in Peking Union Medical College Hospital,case 1 was 2 years old and case 2 was 5 years old.Genomic DNA was extracted from leucocytes in the 2 patients and 2 mothers' cultured amniocytes.IDUA gene DNA sequence was amplified by polymerase chain reaction(PCR)and the PCR products were sequenced directly.Novel mutations were analyzed in 100 normal chromosomes.Result The genotype of case 1 was p.L238R/c.883InsC,while of case 2 was c.531InsT/p.L346R.The fetal case 1 did not inherit the same pathogenic inherited the same pathogenic mutations with the proband,the genotype of fetal 2 was c.531InsT/p.L346R,in 2 MPS Ⅰ patients,p.L238R,c.883InsC,c.531InsT were novel.The fetal case 1 was diagnosed as normal fetus while the fetus 2 was diagnosed as affected.The results of the two kinds of prenatal diagnostic methods were correspondent with each other.     

造血干细胞移植治疗黏多糖贮积症Ⅱ型代谢指标分析

目的从实验室代谢指标探讨黏多糖贮积症Ⅱ型患儿造血干细胞移植治疗后的疗效。方法回顾分析23例男性黏多糖贮积症Ⅱ型患儿造血干细胞移植治疗年龄及治疗前后外周血白细胞艾杜糖醛酸-2-硫酸酯酶(IDS)活性、尿黏多糖(GAG)定性和电泳结果变化。结果 23例男性患儿,移植中位年龄为4.5岁(1.75～12岁)。移植前23例患儿IDS活性均显著低于正常值;移植后100天,90.9%(20/22)患儿IDS活性达到正常值;至移植后2年,100%(9/9)患儿IDS活性达到正常值;移植2年后,患儿IDS活性稳定于正常值范围。移植后2年内患儿IDS活性数值变化差异无统计学意义(P0.05)。移植后100天即有53.3%(8/15)患儿尿GAG含量较移植前下降。截止到资料收集时间,75.0%(15/20)患儿移植后尿GAG含量较移植前下降,但仅2例(10.0%,2/20)患儿移植后尿GAG完全转阴。结论造血干细胞移植治疗可恢复黏多糖贮积症Ⅱ型患儿外周血白细胞IDS活性至正常值,但对于降低黏多糖贮积症Ⅱ型患儿尿GAG含量作用有限,其可在一定程度上降低尿GAG含量但大多未至正常水平。     

艾杜糖-2-硫酸酯酶活性测定在黏多糖贮积病Ⅱ型产前诊断中的应用

目的评估黏多糖贮积病Ⅱ型(MPSⅡ)高危孕妇胎儿绒毛和孕妇外周血血浆艾杜糖-2-硫酸酯酶(IDS)活性以及基因分析在MPSⅡ产前诊断中的应用。方法回顾性分析2013年2月至2020年12月在广州市妇女儿童医疗中心进行产前诊断的23例MPSⅡ高危孕妇的酶学检测及基因分析结果, 采用人工底物荧光法检测胎儿绒毛(30例)和血浆(28例)IDS酶活性, 以非高危妊娠孕妇的28例绒毛和34例血浆检测值为对照, 绒毛同时送检基因检测和胎儿性别鉴定。组间比较采用独立样本t检验。结果非MPSⅡ高危孕妇胎儿绒毛和血浆IDS活性正常参考值为绒毛(71.2±23.4) nmol/(mg·4 h), 血浆(611.1±114.5) nmol/(mL·4 h);30例高危胎儿绒毛中8例男性受累胎儿绒毛IDS酶活性为(1.7±0.3) nmol/(mg·4 h), 显著低于11例男性非受累胎儿[(83.2±6.3) nmol/(mg·4 h)]和9例女性非携带者胎儿[(80.0±7.5) nmol/(mg·4 h)](t=10.8、8.8, 均P<0.01)。28份MPSⅡ高危孕妇外周血血浆IDS酶活性中8...     

Recognition and diagnosis of mucopolysaccharidosis II (Hunter syndrome)

Mucopolysaccharidosis II, also known as Hunter syndrome, is a rare, X-linked disorder caused by a deficiency of the lysosomal enzyme iduronate-2-sulfatase, which catalyzes a step in the catabolism of glycosaminoglycans. In patients with mucopolysaccharidosis II, glycosaminoglycans accumulate within tissues and organs, contributing to the signs and symptoms of the disease. Mucopolysaccharidosis II affects multiple organs and physiologic systems and has a variable age of onset and variable rate of progression. Common presenting features include excess urinary glycosaminoglycan excretion, facial dysmorphism, organomegaly, joint stiffness and contractures, pulmonary dysfunction, myocardial enlargement and valvular dysfunction, and neurologic involvement. In patients with neurologic involvement, intelligence is impaired, and death usually occurs in the second decade of life, whereas those patients with minimal or no neurologic involvement may survive into adulthood with normal intellectual development. Enzyme replacement therapy has emerged as a new treatment for mucopolysaccharidosis disorders, including Hunter syndrome. The purpose of this report is to provide a concise review of mucopolysaccharidosis II for practitioners with the hope that such information will help identify affected boys earlier in the course of their disease.     

Non-viral transfer approaches for the gene therapy of mucopolysaccharidosis type II (Hunter syndrome)

Aims : Hunter syndrome is a rare X-linked lysosomal storage disorder caused by the deficiency of the housekeeping enzyme iduronate-2-sulphatase (IDS). Deficiency of IDS causes accumulation of undegraded dermatan and heparan-sulphate in various tissues and organs. Approaches have been proposed for the symptomatic therapy of the disease, including bone marrow transplantation and, very recently, enzyme replacement. To date, gene therapy strategies have considered mainly retroviral and adenoviral transduction of the correct cDNA. In this paper, two non-viral somatic gene therapy approaches are proposed: encapsulated heterologous cells and muscle electro-gene transfer (EGT). Methods : Hunter primary fibroblasts were co-cultured with either cell clones over-expressing the lacking enzyme or with the same incorporated in alginate microcapsules. For EGT, plasmid vector was injected into mouse quadriceps muscle, which was then immediately electro-stimulated. Results : Co-culturing Hunter primary fibroblasts with cells over-expressing IDS resulted in a three- to fourfold increase in fibroblast enzyme activity with respect to control cells. Fibroblast IDS activity was also increased after co-culture with encapsulated cells. EGT was able to transduce genes in mouse muscle, resulting in at least a tenfold increase in IDS activity 1–5 weeks after treatment.
Conclusion : Although preliminary, results from encapsulated heterologous cell clones and muscle EGT encourage further evaluations for possible application to gene therapy for Hunter syndrome.     

Non-viral transfer approaches for the gene therapy of mucopolysaccharidosis type II (Hunter syndrome)

AIMS: Hunter syndrome is a rare X-linked lysosomal storage disorder caused by the deficiency of the housekeeping enzyme iduronate-2-sulphatase (IDS). Deficiency of IDS causes accumulation of undegraded dermatan and heparan-sulphate in various tissues and organs. Approaches have been proposed for the symptomatic therapy of the disease, including bone marrow transplantation and, very recently, enzyme replacement. To date, gene therapy strategies have considered mainly retroviral and adenoviral transduction of the correct cDNA. In this paper, two non-viral somatic gene therapy approaches are proposed: encapsulated heterologous cells and muscle electro-gene transfer (EGT). METHODS: Hunter primary fibroblasts were co-cultured with either cell clones over-expressing the lacking enzyme or with the same incorporated in alginate microcapsules. For EGT, plasmid vector was injected into mouse quadriceps muscle, which was then immediately electro-stimulated. RESULTS: Co-culturing Hunter primary fibroblasts with cells over-expressing IDS resulted in a three- to fourfold increase in fibroblast enzyme activity with respect to control cells. Fibroblast IDS activity was also increased after co-culture with encapsulated cells. EGT was able to transduce genes in mouse muscle, resulting in at least a tenfold increase in IDS activity 1-5 weeks after treatment. CONCLUSION: Although preliminary, results from encapsulated heterologous cell clones and muscle EGT encourage further evaluations for possible application to gene therapy for Hunter syndrome.     

Enzyme replacement therapy in mucopolysaccharidosis type II (Hunter syndrome): a preliminary report

Mucopolysaccharidosis type II (MPS II; Hunter syndrome) is an X-linked disease caused by a deficiency of the enzyme iduronate-2-sulphatase (IDS), which results in the lysosomal accumulation of glycosaminoglycans (GAG). This paper describes a knockout mouse model of MPS II which has been used to assess the effect of enzyme replacement therapy. Therapy with IDS results in a marked decrease in urinary GAGs, as well as reduced GAG accumulation in several tissues. These studies have been used to support the first clinical trial of recombinant IDS in patients with Hunter syndrome.     

Enzyme replacement therapy in mucopolysaccharidosis type II (Hunter syndrome): a preliminary report

Mucopolysaccharidosis type II (MPS II; Hunter syndrome) is an X-linked disease caused by a deficiency of the enzyme iduronate-2-sulphatase (IDS), which results in the lysosomal accumulation of glycosaminoglycans (GAG). This paper describes a knockout mouse model of MPS II which has been used to assess the effect of enzyme replacement therapy. Therapy with IDS results in a marked decrease in urinary GAGs, as well as reduced GAG accumulation in several tissues. These studies have been used to support the first clinical trial of recombinant IDS in patients with Hunter syndrome.     

The presenting features of mucopolysaccharidosis type IH (Hurler syndrome)

The presenting features of 39 patients with mucopolysaccharidosis (MPS) type IH are described. The mean age at diagnosis was approximately 9 months and it is difficult to see how this can be reduced without consideration of newborn screening. An earlier age at diagnosis is likely to lead to better results following therapy such as bone marrow transplantation. Clinical features which should arouse suspicion of MPS IH include frequent ENT surgery and recurrent herniae. Clinical vigilance is needed for early diagnosis