中国人遗传性高铁血红蛋白血症NADH-细胞色素b5还原酶基因L72P突变

目的：鉴定导致中国人遗传性高铁血红蛋白血症（ＲＣＭ）的ＮＡＤＨ－细胞色素ｂ５还原酶（ｂ５Ｒ）基因突变类型，探讨ＲＣＭ发病的分子基础。方法：逆转录－聚合酶链反应产物直接测序和ｃＤＮＡ克隆测序分析先证者的ｂ５Ｒ编码基因；限制性酶切分析其基因组ＤＮＡ。结果：发现一例ＲＣＭ患者ｂ５Ｒ基因第７２密码子存在新的错义突变（ＣＴＣ→ＣＣＣ）。结论：该突变导致ｂ５Ｒ蛋白第７２位亮氨酸被脯氨酸替换（Ｌ７２Ｐ）是该先证者致病的分子基础；进一步证实Ⅰ型ＲＣＭ患者的ｂ５Ｒ基因突变多发生在近５′端部分。     

中国人遗传性高铁血红蛋白血症NADH—细胞色素b5还原酶基因L …

目的：鉴定导致中国人遗传性高铁血红蛋白血症（ＲＣＭ）的ＮＡＤＨ－细胞色素ｂ５还原酶（ｂ５Ｒ）基因突变类型，探讨ＲＣＭ发病的分子基础。方法：逆转录－聚合酶链反应产物直接测序和ｃＤＮＡ克隆测定分析先证者的ｂ５Ｒ编码基因，限制性酶切分析其基因组ＤＮＡ。结果；发现一例ＲＣＭ患者ｂ５Ｒ基因第７２密码子存在新的错义突变（ＣＴＣ→ＣＣＣ）。结论：该突变导致ｂ５Ｒ蛋白第７２位亮氨酸被脯氨酸替换（Ｌ７２Ｐ）是该先证     

一种新的NADH-细胞色素b5还原酶基因C203Y突变

我中心从９０年代初起共对５个家庭的１５例遗传性高铁血红蛋白血症（ＲＣＭ）患者的ＮＡＤＨ细胞色素ｂ５还原酶（Ｃｙｔｂ５Ｒ）进行了生化、免疫学测试，并对其ｂ５ＲｃＤＮＡ基因进行了序列分析和限制性片段长度多态性分析，已发现并报道了两种基因突变类型（Ｒ５７...     

细胞色素b5还原酶基因L72P突变的分子诊断

１９９８年,我们曾报道一隐性遗传性高铁血红蛋白血症（ＨＭ）先证者的基因序列［１］,发现了细胞色素ｂ５还原酶（ｂ５Ｒ）基因Ｌ７２Ｐ（ＣＴＣ→ＣＣＣ）突变。运用ＰＣＲ限制性片段长度多态性（ＲＦＬＰ）方法,分析家系其他成员的ｂ５Ｒ基因,证明ＰＣＲ结合ＡｐａⅠ限制性内切酶分析可用于ｂ５Ｒ基因Ｌ７２Ｐ突变的基因诊断。一、材料和方法１模板制备：取先证者［１］之兄、父、母及正常成人外周全血细胞２００μｌ,分别提取其基因组ＤＮＡ。２目的ＤＮＡ片断的扩增：使用Ｓａｇｏｎ公司合成、用于扩增ｂ５Ｒ基因片段（含３…     

中国人遗传性高铁血红蛋白血症二个家系所见Gytb5R基因Arg^57…

目的：探明遗传性高铁血红蛋白血症ＮＡＤＨ－细胞色素ｂ５还原酶（Ｃｙｔｂ５Ｒ）缺陷的分子机制。方法：用逆转录－多聚酶链反应（ＲＴ－ＰＣＲ）方法，克隆３个遗传性高铁血红蛋白血症家系Ｃｙｔｂ５Ｒ９２１ｂｐ的ｃＤＮＡ编码序列，并用限制性酶切ＰＣＲ产物分析３个家系的基因组ＤＮＡ。结果：２个家系存在Ａｒｇ＾５７→Ｇｌｎ突变，３个家系均未发现Ｇｌｕ＾２２２→ｇｌｙ突变。结论：Ａｒｇ＾２２２→Ｇｌｎ突变是中国人民     

中国人遗传性高铁血红蛋白血症二个家系所见 Cytb5R 基因 Arg~(57)→Gln 突变

目的：探明遗传性高铁血红蛋白血症ＮＡＤＨ－细胞色素ｂ５还原酶（Ｃｙｔｂ５Ｒ）缺陷的分子机制。方法：用逆转录－多聚酶链反应（ＲＴ－ＰＣＲ）方法，克隆３个遗传性高铁血红蛋白血症家系Ｃｙｔｂ５Ｒ９２１ｂｐ的ｃＤＮＡ编码序列，并用限制性酶切ＰＣＲ产物分析３个家系的基因组ＤＮＡ。结果：２个家系存在Ａｒｇ５７→Ｇｌｎ突变，３个家系均未发现Ｇｌｕ２２２→Ｇｌｙ突变。结论：Ａｒｇ５７→Ｇｌｎ突变是中国人遗传性高铁血红蛋白血症的致病原因之一。     

一例凝血因子Ⅷ B区错义突变导致重型血友病A

目的：检测一例重型血友病Ａ患者（ＳＨ９）的基因突变。方法：用ＰＣＲ、变性梯度凝胶电泳（ＤＧＧＥ）和ＤＮＡ测序检测因子Ⅷ基因突变。先用Ｓｏｕｔｈｅｒｎｂｌｏｔｉｎｇ排除内含子２２倒位，然后应用ＰＣＲ对凝血因子Ⅷ基因进行扩增。扩增范围包括所有外显子及其侧翼内含子序列。结果：片段１４２在ＤＧＧＥ中泳动异常。ＤＮＡ测序证实Ｃ２５３５Ａ导致Ｂ区错义突变８２６Ａｓｐ（ＧＡＣ）→Ｇｌｕ（ＧＡＡ）。结论：该突变可能是导致重型血友病Ａ的原因，但有待进一步研究证实。     

对142例β地中海贫血基因携带者进行缺失型α地中海贫血1基因分析

目的了解广东地区常见的β地中海贫血（地贫）与α地贫１复合存在的发生率。方法应用聚合酶链反应（ＰＣＲ）技术对１４２例经筛查确定为轻型β地贫的成人血样ＤＮＡ进行α地贫１基因检测,阳性者又应用突变引物ＰＣＲ特异扩增或用等位基因特异寡核苷酸探针反向点杂交（ＡＳＯ／ＲＤＢ）技术,确定其β地贫基因突变类型。结果１４２例中有１３例轻型β地贫样本同时合并有α地贫１基因,占总数的９１５％,其β地贫基因的突变类型分别是：ＣＤ４１４２（－ＴＣＴＴ）突变５例,ＩＶＳ２６５４（Ｃ→Ｔ）突变３例,ＣＤ１７（Ａ→Ｔ）突变２例,ＣＤ７１７２（＋Ａ）、ＣＤ４３（Ｇ→Ｔ）和－２８（Ａ→Ｇ）突变各１例。结论β地贫复合α地贫１的双重杂合子在轻型β地贫个体中的发生率较高,是该地区在地贫的遗传咨询和产前诊断工作中值得重视的一个问题。     

N-甲基天冬氨酸受体拮抗剂AP-5在海马对兔P3波电位的作用

目的推测Ｎ甲基天冬氨酸受体（ＮｍｅｔｈｙｌＤａｓｐａｒａｔｅｒｅｃｅｐｔｏｒ,ＮＭＤＡＲ）的兴奋性突触后电位（ｅｘｃｉｔａｔｏｒｙｐｏｓｔｓｙｎａｐｔｉｃｐｏｔｅｎｔｉａｌｓ,ＥＰＳＰ）活动对兔Ｐ３波的作用。方法采用ＮＭＤＡＲ竞争性拮抗剂ＡＰ５（３．１２５、６．２５、１２．５ｍｍｏｌ／Ｌ）在海马ＣＡ１、ＣＡ３微量注入,观察Ｐ３波电位变化。结果ＡＰ５在ＣＡ１区呈一定量效依赖延长Ｐ３ａ波潜伏期,在ＣＡ１、ＣＡ３为明显量效依赖延长Ｐ３ｂ波潜伏期,ＡＰ５对Ｐ３ａ、Ｐ３ｂ波电压振幅无明显影响。结论ＣＡ１区ＮＭＤＡＲＥＰＳＰ活动是Ｐ３ａ波发生相关神经元兴奋的易化因素,可能是海马实施对Ｐ３ａ波潜伏期调节的重要机制。ＣＡ１、ＣＡ３区ＮＭＤＡＲＥＰＳＰ可能共同对Ｐ３ｂ波发生相关神经元兴奋起易化作用,故可影响其潜伏期。     

变性梯度凝胶电泳检测到四例新的FⅨ基因突变

目的：研究凝血因子Ⅸ的基因突变。方法：应用聚合酶链反应（ＰＣＲ）和变性梯度凝胶电泳（ＤＧＧＥ）筛选技术，分析了１２例血友病Ｂ患者ＦⅨ基因的全部８个外显子，剪接区及３′，５′端部分非编码区，并对ＤＧＧＥ行为异常片段进行双脱氧链终止法ＤＮＡ序列分析。结果：发现４例新的基因突变，分别位于ＦⅨ基因第１号外显子Ｔ（ＴＧＴ）１１１Ｇ（ＧＧＴ），导致Ｃｙｓ－１９Ｇｌｙ；第３号内含子剪接位点Ｃ１０３８０Ｔ和第８号外显子Ａ（ＴＡＣ）３０９１８Ｇ（ＴＧＣ），导致Ｔｙｒ２６６Ｃｙｓ；第８号外显子Ａ（ＡＣＧ）３１００７Ｃ（ＣＣＧ），导致Ｔｈｒ２９９Ｐｒｏ。结论：阐明血友病Ｂ的点突变有助于进一步了解ＦⅨ蛋白各功能域的精细功能，并为血友病Ｂ家系携带者检测和产前诊断提供了一个重要的遗传信息。     

遗传性高铁血红蛋白血症分子诊断方法的研究

目的 探讨遗传性高铁血红蛋白血症的分子诊断方法。方法 采用RT-PCR和PCR产物直接测序法,对3例遗传性高铁血红蛋白血症患者细胞色素b5还原酶(b5R)cDNA编码区序列进行分析。通过基因组DNA的PCR-限制性酶切或PCR-序列测定,验证cDNA策略所检出的突变。结果 患者A的b5R cDNA在第527位碱基呈T/C杂合状态,第608位碱基呈G/A杂合状态;患者B的b5R cDNA在第170位碱基和第179位碱基均呈G/A杂合状态;患者C的b5R cDNA在第608位碱基呈G/A杂合状态,第791位碱基呈C/T杂合状态。基因组DNA策略与cDNA策略所得结果一致。结论 建立了遗传性高铁血红蛋白血症的分子诊断方法,并在3例患者中发现了3个以复合杂合子形式存在的、新的b5R基因突变。     

NADH-细胞色素b5还原酶突变型蛋白的结构与功能研究

目的 探讨NADH-细胞色素b5还原酶基因突变引起遗传性高铁血红蛋白血症的分子病理机制。研究突变型（b5R）蛋白结构和功能的关系。方法 用基因重组技术将野生型和突变型（L72P）b5R cDNA克隆于pGEX-2T载体,在大肠杆菌BL21中诱导表达。Western印迹鉴定表达的蛋白为CST-b5R融合蛋白。应用谷胱甘肽-Sepharose 4B亲扫层析,还原型谷胱甘肽洗脱得到纯化的GST-b5R和GST-b5R L72P融合蛋白,比较GST-b5R和GST-b5R L72P酶活性。结果 突变型酶活性低,为野生型的3％。结论 L72P突变可引起蛋白质二级结构改变从而导致酶的活性下降。     

A compound heterozygote for a novel missense mutation (G105R) in exon 3 and a missense mutation (D204E) in exon 5 of the lipoprotein lipase gene in a Japanese infant with hyperchylomicronaemia

We systematically investigated the molecular defects resulting in primary lipoprotein lipase (LPL) deficiency in a Japanese male infant (hereafter called 'the patient') with severe fasting hypertriglyceridaemia (type I hyperlipoproteinaemia). The primary LPL deficiency was diagnosed on the basis of the findings that no LPL activity was detected in post-heparin plasma (PHP) and that the immunoreactive LPL mass in PHP was less than 2% of the control level. The patient was a compound heterozygote for a novel missense mutation (G(568)GA-->AGA/Gly(105)-->Arg; G105R) in exon 3 and a missense mutation (GAC(867)-->GAG/Asp(204)-->Glu; D204E) in exon 5 of the LPL gene. The biological significance of both missense mutations was examined by an in vitro study of the expression of the mutant G105R LPL cDNA and D204E LPL cDNA in COS-1 cells. Both mutant LPLs were catalytically inactive and were barely released by heparin from the expressing COS-1 cells. These findings explain the failure to detect LPL activity and immunoreactive LPL mass in the patient's PHP. The G105R allele could be detected by digestion with the BsmAI restriction enzyme, and the D204E allele by digestion with HincII. The patient inherited the G105R allele from his mother and the D204E allele from his father. His parents were heterozygotes for the corresponding mutant allele, but normolipidaemic. The novel G105R missense mutation could not be detected by conventional analysis of single-strand conformation polymorphism, but it was identified by extensive sequencing of the entire exons and their flanking regions in the LPL gene.     

Detection of PHKA2 gene mutation in four Japanese patients with hepatic phosphorylase kinase deficiency

We analyzed the PHKA2 gene in four Japanese families with hepatic phosphorylase kinase (PhK) deficiency. Mutational analysis of PHKA2 cDNA was performed by reverse-transcribed polymerase chain reaction (RT-PCR) and direct sequencing, and each mutation was confirmed on the genomic DNA. In boys with low erythrocyte PhK activity (i.e., x-linked liver glycogenosis [XLG] type I), deletion of exon 2 (splice site mutation of 79-1 G > T) or nonsense mutation of Q1169X or R497X was identified. However, missense mutation of R295C was identified in one boy with normal erythrocyte PhK activity (i.e., XLG type II). This mutation was not found in 100 control alleles, and was considered responsible for presentation of the XLG type II phenotype. Excluding Q1169X, all mutations detected in this study represented novel mutations. All mothers were found to be heterozygous carriers of the mutations. Gene analysis was confirmed to represent a useful procedure for diagnosing XLG type II, for which liver biopsy had previously been required to detect hepatic PhK deficiency.     

Identification of a point mutation resulting in a heat-labile adenosine deaminase (ADA) in two unrelated children with partial ADA deficiency.

We have determined the mutation in a child with partial adenosine deaminase (ADA) deficiency who is phenotypically homozygous for a mutant ADA gene encoding a heat-labile enzyme (Am. J. Hum. Genet. 38: 13-25). Sequencing of cDNA demonstrated a C to A transversion that results in the replacement of a proline by a glutamine residue at codon 297. As this mutation generated a new recognition site in exon 10 of genomic DNA for the enzyme Alu I, Southern blot analysis was used to establish that this child was indeed homozygous for the mutation. The abnormal restriction fragment generated by this mutation was also found in a second partially ADA-deficient patient who phenotypically is a genetic compound and also expresses a heat-labile ADA (in addition to a more acidic than normal ADA) (Am. J. Hum. Genet. 38: 13-25). Sequencing of cDNA clones from the second patient established the identical codon 297 mutation. Transfection of the mutant cDNA into heterologous cells resulted in expression of a heat-labile ADA of normal electrophoretic mobility and isoelectric point, properties exhibited by the ADA in the patients' cells.     

F9基因Arg327Ile新突变导致血友病B的分子发病机制研究

目的探讨F9基因Arg327Ile(R327I)突变导致血友病B的分子发病机制研究。方法对1名血友病B患者作实验室和基因诊断,定点突变法构建F9基因R327I突变的表达质粒;瞬时转染HEK293细胞,一期法检测细胞上清液中凝血因子Ⅸ活性(FⅨ∶C),ELISA法检测细胞上清液和裂解中FⅨ抗原(FⅨ∶Ag),Western blotting检测R327I突变蛋白的分子量及表达量;免疫荧光共定位染色法检测突变蛋白在内质网和高尔基体内分布。结果瞬时表达显示该患者突变细胞标本上清液中R327I突变型FⅨ∶C为野生型的4.49%,明显降低;细胞上清液和裂解液FⅨ∶Ag分别为野生型的31%和129%,为交叉反应物质减低型(CRMR)。Western blotting显示细胞上清液中R327I突变蛋白分子量与野生型相同,但含量比野生型明显降低;免疫荧光共定位染色显示R327I突变蛋白在内质网中分布较野生型多,而在高尔基体中较野生型少。结论 F9基因R327I突变影响蛋白质合成和分泌,突变蛋白较野生型表达量偏低,同时R327I突变蛋白存在凝血功能缺陷从而导致血友病B。     

Deficiency of UDP-galactose:N-acetylglucosamine beta-1,4-galactosyltransferase I causes the congenital disorder of glycosylation type IId

Deficiency of the Golgi enzyme UDP-Gal:N-acetylglucosamine beta-1,4-galactosyltransferase I (beta4GalT I) (E.C.2.4.1.38) causes a new congenital disorder of glycosylation (CDG), designated type IId (CDG-IId), a severe neurologic disease characterized by a hydrocephalus, myopathy, and blood-clotting defects. Analysis of oligosaccharides from serum transferrin by HPLC, mass spectrometry, and lectin binding revealed the loss of sialic acid and galactose residues. In skin fibroblasts and leukocytes, galactosyltransferase activity was reduced to 5% that of controls. In fibroblasts, a truncated polypeptide was detected that was about 12 kDa smaller in size than wild-type beta4GalT I and that failed to localize to the Golgi apparatus. Sequencing of the beta4GalT I cDNA and gene revealed an insertion of a single nucleotide (1031-1032insC) leading to premature translation stop and loss of the C-terminal 50 amino acids of the enzyme. The patient was homozygous and his parents heterozygous for this mutation. Expression of a corresponding mutant cDNA in COS-7 cells led to the synthesis of a truncated, inactive polypeptide, which localized to the endoplasmic reticulum.