一例戊二酸血症Ⅰ型患儿的 GCDH基因变异分析

目的:明确1例经串联质谱筛查诊断为戊二酸血症Ⅰ型患儿的遗传学病因。方法:提取患儿及其双亲外周血基因组DNA,采用基因捕获技术进行高通量测序,对可疑基因变异位点进行Sanger测序验证和生物信息学预测。结果:患儿存在 GCDH基因c.523G>A与c.1190T>C位点复合杂合变异,c.523G>A来源于父亲...     

八例戊二酸尿症Ⅰ型患者的GCDH基因突变分析

目的 分析8例戊二酸尿症Ⅰ型(glutaric aciduria type Ⅰ,GA-1)患者的GCDH基因突变情况.方法 对8例经尿液及血液生化检查诊断为GA-1的患者及其部分家系成员,采集外周静脉血,应用蛋白酶K-盐析法提取DNA,PCR产物直接测序法,进行GCDH基因的所有外显子及侧翼序列的突变筛查.结果 8例GA-1患者中,7例为经典的婴幼儿发病,1例为成年晚发型.基因分析证实8例先证者均存在GCDH基因突变,其中5例为复合杂合性突变,符合隐性遗传;另3例只发现1个杂合性突变位点.共发现9种突变类型,其中c.148T＞C、c.371G＞A、909 delC和c.263G＞A是4个新的突变位点.结论 首次在国内报道8例GA-1患者携带GCDH基因突变,其中1例为罕见的成年晚发型.发现了4个新的突变位点,丰富了GCDH基因的突变谱.     

戊二酸血症1型诊治专家共识

戊二酸血症1型(glutaricacidemia type 1,GA1)是一种常染色体隐性遗传病,由于戊二酰辅酶A脱氢酶活性降低或缺失导致赖氨酸、羟赖氨酸及色氨酸分解代谢受阻,代谢产物戊二酰肉碱、戊二酸等在体内异常蓄积,引起代谢紊乱,主要导致神经系统受损。患者临床表现为巨颅、肌张力障碍、运动障碍及发育落后等,常在婴幼儿期由于感染、疫苗接种及手术等诱发急性脑病。由于GA1罕见,临床表现与其他神经系统疾病表现类似,特异性不强,易漏诊或误诊。为了早期诊断和治疗,改善患儿预后,指导临床医师合理诊治,由国内儿科内分泌遗传代谢科专家共同讨论,结合国内外研究进展及国际指南,制定了本共识。     

三例酪氨酸血症Ⅰ型患者的临床表现及基因突变分析

目的 分析酪氨酸血症Ⅰ型患儿的临床资料和基因突变情况,探讨基因型与临床表型的关系.方法 采用串联质谱检测血酪氨酸、苯丙氨酸和琥珀酰丙酮水平,气相质谱检测尿琥珀酰丙酮及有机酸,确诊酪氨酸血症工型,对确诊患儿进行基因突变检测分析.结果 确诊的3例患者中2例为急性型,1例为亚急性型,表现为肝肿大,血酪氨酸和琥珀酰丙酮显著增高.基因突变分析检测到5种突变类型:c.455G>A(W152X)、 c.520C>T(R174X)、c.974_976delCGAinsGC、c.1027 G>A(G343R)、c.1100 G>A(W367X),其中c.455G>A(W152X)、c.974_976delCGAinsGC、c.1100 G>A(W367X)为新突变.结论 应用串联质谱检测血酪氨酸及琥珀酰丙酮水平、气相质谱检测检测尿琥珀酰丙酮可诊断酪氨酸血症工型.基因突变检测结果为遗传咨询以及后续研究提供依据.     

单纯型甲基丙二酸血症家系MUT基因变异的分析及产前诊断CSCD

目的对20个单纯型甲基丙二酸血症家系MUT基因的变异进行测序分析,为家系产前诊断提供依据。方法应用PCR产物直接测序法对20例单纯型甲基丙二酸血症患儿及其父母的MUT基因进行变异检测和分析,明确基因变异情况,并对9名孕妇进行产前诊断。结果20例患儿的家系共检测出19种MUT基因变异,最常见的变异为C.323G〉A（P．Arg108His）、c．1106G〉A（P．Arg369His）、C．729_730insTT（P．D244Lfs＊39）和c．1107dupT（P．T370Yfs＊22）。C．920_923delTCTT（P．F307SIs＊6）、C．419T〉C（P．Leu140Pro）和C．613G〉A（P．Glu205Lys）为未报道过的新变异。Polyphen2和Mutationtaster软件预测这3个变异均可能致病。产前诊断结果显示1例胎儿未检测到MUT基因变异,3例胎儿为MUT基因杂合变异携带者,5例胎儿为MUT基因复合杂合变异或纯合变异患儿。MUT基因正常或杂合变异携带者胎儿的家系选择继续妊娠,而MUT基因纯合变异或复合杂合变异胎儿的家系均选择终止妊娠,胎儿娩出后随访结果与产前诊断结果一致。结论MUT基因突变分析结果为家系的产前诊断提供了依据,新变异的检出丰富了MUT基因突变谱。     

胎儿全外显子组测序诊断戊二酸血症ⅡC型一例

目的对1例孕期超声提示肾脏增大、回声增强的胎儿进行全外显子组测序, 以明确其病因。方法收集胎儿的影像学资料, 穿刺收集羊水样本20 mL, 抽取胎儿父母静脉血样各2 mL。提取羊水DNA进行文库构建和全外显子组测序, 对与胎儿表型相关的变异位点进行家系Sanger测序验证。结果产前超声提示胎儿双肾增大、回声增强且肾内存在多个小囊肿。全外显子组测序发现胎儿ETFDH基因存在致病性复合杂合变异c.3G>C与c.1436dupA, 家系Sanger测序提示上述变异分别遗传自其母亲和父亲。结论结合临床表现与全外显子组测序的结果, 胎儿被诊断为戊二酸血症ⅡC型, 其病因为ETFDH基因复合杂合变异。上述结果为胎儿的产前诊断及遗传咨询提供了依据。胎儿全外显子组测序将成为产前诊断的重要手段。     

先天性高铁血红蛋白血症I型1例

临床病例 患儿，女，70天，全身皮肤及口唇青紫7天伴轻微腹泻，在当地治疗腹泻止，经输氧等治疗，紫绀无改善，不吸奶，恶心，呕吐，病情加重转来我院，于1990年6月27日入院．     

3例瓜氨酸血症I型患儿基因与外周血代谢物表达特点

目的 探究瓜氨酸血症I型患儿基因与外周血代谢物表达特点,提高临床对瓜氨酸血症I型的认识.方法 收集瓜氨酸血症I型患儿病例信息,利用液相串联质谱技术对3例瓜氨酸血症I型患儿进行外周血代谢物的测定,归纳总结瓜氨酸血症I型患儿外周血小分子代谢物表达特点,并且对瓜氨酸血症I型患儿进行高通量二代测序,获取患儿的基因突变类型.结果...     

糖原累积病I b型1例的临床和分子遗传分析

目的 初步探讨1例糖原累积病I b型(GSD I b)患者的临床特点和致病基因,分析该疾病发生的分子遗传机制.方法 收集患者临床资料,抽提患者外周血白细胞基因组DNA,通过多聚酶链反应扩增葡萄糖-6-磷酸酶转位酶基因SLC37A4的9个外显子,用DNA直接测序法确定其突变位点.结果 患者临床表现及实验室检查完全符合GSD I b.经PCR测序发现SLC37A4基因第3外显子572位碱基C→T纯合突变(c.572 C>T),造成第191位的脯氨酸被亮氨酸替代(P.P191L),导致葡萄糖-6-磷酸转位酶活性下降.结论 SLC37A4基因突变导致的葡萄糖-6-磷酸转位酶结构改变是该GSD I b患者临床表现的分子遗传基础.P191L纯合突变在中国大陆的报道尚属首次.相信不久DNA突变分析将会成为糖原累积病I b型的主要确诊方法.     

Glutaryl-CoA dehydrogenase mutations in glutaric acidemia (type I): Review and report of thirty novel mutations

Glutaric acidemia type I (GA1) is caused by mutations in the gene encoding the enzyme glutaryl-CoA dehydrogenase (GCD). Sixty-three pathogenic mutations identified by several laboratories are presented, 30 of them for the first time, together with data on expression in Escherichia coli and relationship to the clinical and biochemical phenotype. In brief, many GCD mutations cause GA1, but none is common. There is little if any relationship between genotype and clinical phenotype, but some mutations, even when heterozygous, seem especially common in patients with normal or only minimally elevated urine glutaric acid. Hum Mutat 12:141–144, 1998. © 1998 Wiley-Liss, Inc.     

Recurrent and novel mutations of GCDH gene in Chinese glutaric acidemia type I families

Glutaric acidemia type I is caused by mutations of the glutaryl-CoA dehydrogenase (GCDH) gene resulting in loss of GCDH enzyme activity. Patients present with progressive dystonia and lesions in basal ganglia. Dietary treatment, when instituted from the early neonatal period, markedly reduces dystonia and morbidity. Early diagnosis and prenatal diagnosis will be facilitated by knowledge of locally prevalent GCDH mutations. Several common GCDH mutations have been found in different ethnic groups. GCDH mutations were studied in 5 Chinese glutaric acidemia type I families. We detected two novel recurrent mutations (A219T and IVS10-2A>C) which were found in two unrelated families. An asymptomatic carrier of IVS10-2A>C was also found on screening of 120 individuals. Other mutations were identified, including two other novel (R386G & IVS3+1G>A) and two known mutations (G178R & R355H). Fibroblasts from patients carrying the novel mutations were confirmed to be deficient for GCDH activity. This is the first report of GCDH mutations describing recurrent mutations in Chinese patients. The carrier rate of IVS10-2A>C may be particularly high in Chinese.     

Novel mutations of the glutaryl-CoA dehydrogenase gene in two Japanese patients with glutaric aciduria type I

We identified three different point mutations in the glutaryl-CoA dehydrogenase (GCDH) gene in two unrelated Japanese patients with glutaric aciduria type I (GA-I). One patient was a homozygote for Arg355His and the other a compound heterozygote for Ser305Leu and Met339Val. Arg355His and Met339Val are mutations hitherto undescribed, and all three mutations are predicted to alter the secondary structure of GCDH. Molecular analysis is useful for definite diagnosis and/or prenatal diagnosis of GA-I. Am. J. Med. Genet. 80:327–329, 1998. © 1998 Wiley-Liss, Inc.     

Mitochondrial energetic impairment in a patient with late‐onset glutaric acidemia Type 2

Glutaric acidemia type 2 (GA2), also called multiple acyl‐CoA dehydrogenase deficiency, is an autosomal recessive disorder of fatty acid, amino acid, and choline metabolism resulting in excretion of multiple organic acids and glycine conjugates as well as elevation of various plasma acylcarnitine species (C4–C18). It is caused by mutations in the ETFA, ETFB, or ETFDH genes which are involved in the transfer of electrons from 11 flavin‐containing dehydrogenases to Coenzyme Q₁₀ (CoQ₁₀) of the mitochondrial electron transport chain (ETC). We report a patient who was originally reported as the first case with primary myopathic CoQ₁₀ deficiency when he presented at 11.5 years with exercise intolerance and myopathy that improved after treatment with ubiquinone and carnitine. At age 23, his symptoms relapsed despite increasing doses of ubiquinone and he was shown to have biallelic mutations in the ETFDH gene. Treatment with riboflavin was started and ubiquinone was changed to ubiquinol. After 4 months, the patient recovered his muscle strength with normalization of laboratory exams and exercise tolerance. Functional studies on fibroblasts revealed decreased levels of ETFDH as well as of very long‐chain acyl‐CoA dehydrogenase and trifunctional protein α. In addition, the mitochondrial mass was decreased, with increased formation of reactive oxygen species and oxygen consumption rate, but with a decreased spared respiratory capacity, and decreased adenosine triphosphate level. These findings of widespread dysfunction of fatty acid oxidation and ETC enzymes support the impairment of a larger mitochondrial ETC supercomplex in our patient.     

Phenotypic and genotypic spectrum of Turkish patients with isovaleric acidemia

We aim to investigate the genetic basis of isovaleryl-CoA dehydrogenase (IVD) gene mutations and genotype–phenotype correlations in Turkish patients. Accordingly, bi-directional sequencing was performed to screen 26 patients with isovaleric acidemia (IVA). Nine novels (c.145delC, c.234 + 3G > C, c.506_507insT, p.Glu85Gln, p.Met147Val, p.Ala268Val, p.Ile287Met, p.Gly346Asp and p.Arg382Trp) and six previously reported (c.456 + 2T > C, p.Arg21His, p.Arg21Pro, p.Arg363Cys, p.Arg363His p.Glu379Lys) pathogenic mutations were identified. Pathogenicity of the novel mutations was supported using computational programs. No clear genotype–phenotype correlation could be determined. One of the cases with the novel c.234 + 3G > C mutation has portoseptal liver fibrosis, the clinical condition that was first reported for IVA. This study is the first comprehensive report from Turkey related to IVA genetics that provides information about the high number of disease-causing novel mutations.     

Analysis of NF1 gene mutations in two sporadic patients with neurofibromatosis type 1CSCD

Objective: To detect mutations of the NF1 gene in two sporadic cases with neurofibromatosis type 1 (NF1) and explore their molecular mechanisms. Methods: Clinical data of the two patients was collected. Genomic DNA was extracted from peripheral blood samples. Specific primers were designed to exclude pseudogenes. PCR was performed to amplify all coding exons of the NF1 gene. PCR products were directly sequenced. Results: Two novel mutations of the NF1 gene (c. 1019-1020delCT in exon 9 and c. 7189G> A in exon 48) were respectively identified in the two patients but not among their unaffected parents or 100 healthy controls. Conclusion: Mutations of the NF1 gene may have predisposed to the NF1 in the two patients. © 2018 MeDitorial Ltd. All rights reserved.     

Newborn screening for glutaric aciduria type I in Victoria: treatment and outcome

Between October 2001 and September 2007, a total number of 391,651 neonates were screened in Victoria using Tandem Mass Spectrometry and 6 newborns were diagnosed as having GA I, giving an incidence of 1:65,275 (CI: 1:29,988 = 1:177,861). Another patient was diagnosed through cascade screening of children born before the implementation of the expanded newborn screening program. Patients were treated by mild protein restriction (2–2.5 g/kg/day) and carnitine supplementation when well, focussing on the aggressive management of intercurrent illnesses (temporary cessation of protein intake, increase in calorie intake, IV carnitine, aggressive anti febrile and anti infectious treatment), including prophylactic admissions to hospital. Overall, our patients had 35 admissions to hospital, of which 15 were in the first year of life. None had a post infectious dystonic syndrome. Neuropsychological examinations revealed normal to high cognitive and gross motor function in all patients but one, with some deficiencies in fine motor activities and different levels of speech abnormalities in all patients. Since therapeutic approaches for GA I, although not uniform, are well established and have been documented to be effective, newborn screening for this disorder should prove justified. A therapeutic approach of dietary modification, IV carnitine and aggressive treatment of intercurrent illness seems to prevent the severe neurological complications of GA I. More in-depth consideration of speech and language function is necessary to document specific deficits in children with GA I and plan proactive interventions.     

Identification of novel mutations in the PCCB gene in European propionic acidemia patients

Propionyl‐CoA carboxylase (PCC) is a biotin‐dependent enzyme located in the mitochondrial matrix. Mutations in the PCCA and PCCB genes, which encode the a and b subunits of this heteropolymer, result in propionic acidemia (PA). We report the molecular analysis of b‐deficient patients from Spain and Austria. Subjects were screened for defects affecting the PCCB gene by direct sequencing from genomic PCR products, restriction digests and mRNA analysis by RT‐PCR. Study by western blot of the presence of immunoreactive b‐PCC protein was also performed. A total of four novel sequence variations were found including the point mutations V205D, and M442T, and the frameshift mutation 790‐791insG. Additionaly, a new point change, L17M, was identified on the same allele as 790‐791insG. The missense changes described above were not found in at least 40 control chromosomes analyzed. The Austrian patients were homozygous for V205D. One of the Spanish subjects was heterozygous for M442T and the known mutation c1170insT. The other Spanish patient carried L17M+790‐791insG on one allele, and the described mutation E168K on the other mutant chromosome. The mutations V205D and M442T were confirmed at RNA level and also we have detected the presence of immunoreactive b‐PCC protein translated from these mutant alleles. The patient having L17M+790‐791insG and E168K also presented immunoreactive b‐PCC protein. However, no cDNA product was obtained from the chromosome carrying L17M+790‐791insG. We propose that 790‐791insG, which causes a frameshift and a premature stop codon, is responsible for this finding. In any case, the translation from this mutant cDNA would produce a severily truncated peptide and, in consequence, a non‐functional protein. Expression analysis of all these changes will help us to clarify their structural/functional consequences. Hum Mutat 14:89–90, 1999. © 1999 Wiley‐Liss, Inc.     

Mutation analysis of the GCDH gene in Italian and Portuguese patients with glutaric aciduria type I

Two novel (G390V and X439W) and five already known mutations were identified in a total of 14 GA I alleles from Italy and Portugal. The substitution X439W is a rare type of mutation, which breaks the stop codon of the GCDH gene. As described in other populations, R402W was the most common mutation. Genotype R227P/R402W was found in a patient with low glutarate excretion. Haplotype studies have also been performed.