线粒体DNA3537A→G、4824A→G、5351A→G突变与2型糖尿病的相关性研究

目的研究T2DM患者线粒体ND1基因3537A→G和ND2基因4824A→G、5351A→G突变与T2DM的相关性。方法应用PCR-RFLP技术检测145例T2DM和334例正常对照者（NC）线粒体DNA（mtDNA）3537A→G、4824A→G、5351A→G突变情况。结果NC组mtDNA4824A→G突变率高于T2DM组（P＜0．05）。3537A→G及5351A→G突变率在两组中无统计学差异（P〉0．05）。结论mtDNA4824A→G突变可能为T2DM患病的保护因素。3537A→G及5351A→G突变可能与T2DM不相关。     

COX-2 polymorphisms -765G →C and -1195A→G and colorectal cancer risk

AIM： TO determine the possible modulating effect of the COX-2 polymorphisms, -765G→C and -1195A→G, on the risk of colorectal cancer （CRC） in a Dutch population. METHODS： This case-control study includes 326 patients with CRC and 369 age- and gender-matched controls. Genotypes of the COX-2 polymorphisms -7dEG→C and -1195A→G were determined by polymerase chain reaction-based restriction fragment length polymorphism. COX-2 genotypes and haplotypes were analyzed and odds ratios with 95% confidence intervals were estimated by logistic regression. RESULTS： The -765GG genotype was associated with an increased risk of developing CRC （OR, 1.45; 95% CI, 1.03-2.04）. No significant difference was observed in the genotype distribution of the -1195A→G polymorphism between patients and controls. The GG/AC haplotype was present significantly less often in patients than in controls （OR 0.44; 95% CI, 0.22-0.85）. When the AC, AG and GG haplotypes were investigated separately, the AC haplotype showed a tendency to be less frequent in patients than in controls （OR（AG/AC） 0.78; 95% CI, 0.57-1.06）. CONCLUSION： The -765GG genotype is associated with an increased risk of developing CRC and the G6/ AC haplotype seems to protect against CRC. These findings suggest a modulating role for the COX-2 polymorphisms -765G→C and -1195A→G in the development of CRC in a Dutch population.     

Neonatal cyanosis due to a new (G)γ-globin variant causing low oxygen affinity: Hb F-Sarajevo [(G)γ102(G4)Asn→Thr, AAC>ACC

A baby girl, born at term, presented with severe cyanosis and received oxygen supplementation. Consecutive arterial blood gas analysis showed a pronounced right shift of the saturation curve, suggesting the presence of a hemoglobin (Hb) variant. A new (G)γ-globin variant was detected, namely HBG2:c.308G, which we have named Hb F-Sarajevo, the city from where the baby's parents originate. This A to C transversion exists in cis to the common (A)γ(T) and the resulting mutant Hb molecule exhibits very low oxygen affinity and cooperativity. Its analogue in the β-globin gene is Hb Kansas [β102(G4)Asn→Thr, AAC>ACC].     

线粒体基因np3316G→A突变与糖尿病

目的 了解线粒体ＮＡＤＨ脱氢酶亚单位１（ＮＤ１）基因中的３３１６位点Ｇ→Ａ突变在我国ＤＭ患者中的存在情况。方法 对随机收集的无血缘关系的２６２例２型ＤＭ、０１７例１型ＤＭ患者进行了研究，同时选择我无糖尿病家中占１．９％（５／２６２），１型ＤＭ中占３．６（４／１０９）。在ＧＡＤ抗体阳性的１型ＤＭ中占８．５％（４／４７），而１２２例非糖尿病患者未检出该突变（Ｐ〈０．０１）。结论 ＮＤ１基因３３１６Ｇ→     

Hb G-MAKASSAR [β6(A3)Glu→Ala; CODON 6 (G A G→G C G)]: MOLECULAR CHARACTERIZATION,CLINICAL, AND HEMATOLOGICAL EFFECTS

We report a Thai family in which five members are Hb G-Makassar heterozygotes and one member is, in addition, a heterozygote for β⁰-thalassemia (IVS-I-1, G→T). We confirm that the previously presumed mutation at codon 6 of the β-globin gene is G A G→G C G. Hb G-Makassar heterozygotes are asymptomatic and hematologically normal. The Hb G-Makassar/β⁰-thalassemia compound heterozygote has features of thalassemia minor. A simple and rapid polymerase chain reaction-restriction fragment length polymorphism for the detection of Hb G-Makassar is described.     

Two new mutations in cis on <Superscript>G</Superscript>γ chain of fetal hemoglobin: Hb F-Madrid [Gγ50(D1)Ser→Cys] and [Gγ75(E19)Ile→Thr]

We describe a new structural hemoglobin variant of (G)gamma with two amino acid replacements in cis found in the umbilical cord blood of a neonate in Madrid, Spain. The substitutions were identified on exon 2 of the (G)gamma globin gene, at codon 50 (T CT-->T GT) and at codon 75 (A TA-->A CA). We have named it Hb F-Madrid. The father of the propositus was the carrier of the same (G)gamma chain variant and, moreover, molecular study of alpha genes revealed the loss of an alpha gene (-alpha(3.7)/alpha alpha) both in the propositus and his mother.     

2型糖尿病中线粒体DNA的3316G→A和3394T→C点突变

目的　了解天津地区线粒体DNA点突变 (3 2 43A→G、3 3 16G→A、3 3 94T→C和 3 42 6A→G)与 2型糖尿病的关系。方法　对无血缘关系的 478例 2型糖尿病患者进行研究 ,同时选择 43 0例无糖尿病家族史的糖耐量正常者作为对照 ,用PCR RFLP筛选点突变。结果　 2型糖尿病组 3 3 16点突变发生率为2 .72 % (13 / 478) ,3 3 94点突变发生率为 2 .5 1% (12 / 478) ;两种点突变在对照组发生率分别为 0和 0 .47%(2 / 43 0 ) ,两组比较差异均有显著性 (P <0 .0 1或P <0 .0 5 )。 2型糖尿病组 3 42 6点突变发生率为 0 .42 %(2 / 478) ;对照组未见该突变 ,两组间差异无显著性。两组中皆未发现 3 2 43A→G突变。结论　线粒体DNA 3 3 16G→A和 3 3 94T→C突变与天津地区人群糖尿病的发病有关。     

Hb F‐M‐Osaka [Gγ63(E7)His→Tyr] in a Newborn from Southwest France

We have monitored a sequence of reactions involving hemoglobin (Hb) oxidation in the presence of phospholipid bilayers in carefully characterized buffer systems in order to delineate molecular events that may have cytotoxic effects, some of which may even lead to cellular death of erythrocytes. We followed reactions of subunit cross-linking, heme iron oxidation, heme destruction and iron release in normal (Hb A) and sickle [Hb S or β6(A3)Glu→Val] Hbs under different experimental conditions. Our results show that, in the presence of lipid surfaces, the reaction rates for heme Fe^{+ 2} to Fe^{+ 3} oxidation in Hb A and Hb S molecules were both enhanced by lipid surfaces. However, the extent of the enhancement in Hb A and Hb S was quite different in T5K6.5, a Tris buffer with low ionic strength and low pH. In T5K6.5, the rate constants were 0.8 h^{? 1} for Hb A and 4.3 h^{? 1} for Hb S, a 5-fold difference. This finding supports a published suggestion that sickle Hb exhibits abnormal heme oxidation in erythrocytes of sickle cell disease patients. We found that the rates were quite similar in P110N7.4, a phosphate buffer near physiological conditions. Even in T5K6.5, the lipid surface did not enhance Hb S reactions involving subunit cross-linking, heme destruction, or iron release. These findings suggest that heme oxidation and related reactions may not be responsible for detrimental cellular events in sickle erythrocytes under physiological conditions, as suggested in the literature.     

A Second Observation of the Fetal Methehoglobin Variant HB F-M-Fort Ripley or α2Gγ292(F8)HIS→TYR

We have identified a second baby with the fetal methemoglobin F-M-Fort Ripley. It was observed in a Caucasian infant from Canada; at least eleven additional members of that family were known to have had a neonatal cyanosis similar to that seen in the propositus and in a previously described baby (2). Sequencing of amplified DNA that included (part of) the G_γ gene greatly facilitated the characterization. The G_γx chain was readily isolated by reversed phase high performance liquid chromatography; its quantity was ～12.5% of total γ. Interestingly, the baby also carried the AγT mutation on one chromosome, either in cis or in trans to the Gγx mutation. Hb F-M-Fort Ripley could be isolated in reasonably pure form by DEAE-cellulose chromatography. The isolated Hb Fx was unstable, had spectral changes characteristic for the M-hemoglobins, while its methemqglobin derivative reacted rapidly with cyanide. Oxygen affinity data could not be obtained. It is suggested that the formation of a rather large amount (～25%) of mixed hybrids (α₂G_γX.γ) with low oxygen affinity is the main cause for the occurrence of the neonatal cyanosis.     

线粒体DNA3316G→A基因突变与2型糖尿病的关系

部分学者认为3316G→A点突变可能是2型糖尿病和谷氨酸脱氢酶抗体阳性的1型糖尿病的易感因素,为探讨其相关性,我们于2003年3月～2004年7月进行了以下研究。     

Molecular identification of the novel Gγ-β hybrid hemoglobin: Hb Gγ-β Ulsan (Gγ through 13; β from 19)

Gene fusion is a very rare mechanism that produces hemoglobin variants. Less than ten types of β-like hybrid globins have been reported to date. Herein we identified the first hybrid hemoglobin between Gγ- and β-globins in a five-year-old Korean male who had thalassemia minor feature and triplication of the HBA2 gene (αα/αααα). The novel globin originated from a 27,707-base pair deletion spanning from the HBG2 to HBB gene (NG_000007.3:g.42947_70653del). Its protein sequence included 13 N-terminal amino acids from Gγ-globin, five common amino acids from Gγ- and β-globins, and 128 amino acids from β-globin (Gγ through 13; β from 19). Molecular genetic analyses characterized the hybrid DNA and RNA. Mass spectrometry and de novo protein sequencing successfully identified the fusion peptide in the hybrid hemoglobin. We named this novel hybrid Hb Gγ-β Ulsan. The novel hemoglobin constituted 37.0% of the total hemoglobin and showed reduced oxygen affinity.     

Identification of three novel Hb F variants: Hb F-Hayward [Gγ1(NA1)Gly→Asp, GGT>GAT], Hb F-Chori-I [AγT16(A13)Gly→Asp, GGC>GAC] and Hb F-Chori-II [AγI29(B11)Gly→Glu, GGA>GAA

Three new γ-globin chain mutations were identified in four newborn samples referred to the Hemoglobinopathy Reference Laboratory at the Children's Hospital & Research Center Oakland, Oakland, CA, USA, for diagnostic testing. The variants were characterized by sequencing of amplified γ-globin genes. These three novel variants have been named Hb F-Hayward [(G)γ1(NA1)Gly→Asp, GGT>GAT], Hb F-Chori-I [(A)γ(T)16(A13)Gly→Asp, GGC>GAC] and Hb F-Chori-II [(A)γ(I)29(B11)Gly→Glu, GGA>GAA], respectively. No functional studies could be performed.     

慢性乙型肝炎患者体内病毒基因G→A超突变的检测及分析

载脂蛋白B mRNA编辑酶催化多肽样3G(APOBEC3G)是一种胞嘧啶脱氨酶,是Sheehy等[1]在对人类免疫缺陷病毒 (HIV)进行允许细胞和非允许细胞基因差异表达分析过程 中发现的一种新型抗病毒因子;它能使HIV病毒基因组发生鸟嘌呤(G)→腺嘌呤(A)的碱基突变,致使其病毒基因组不能执行正常的功能而具有抗病毒活性[2].     

载脂蛋白AI基因启动子区域G→A置换 与冠心病关系的研究

目的探讨载脂蛋白AI(apoAI)基因启动子区域—78bp位点G→A置换与血浆高密度脂蛋白(HDL)含量及冠心病(CHD)的关系。方法PCR扩增apoAI基因启动子—259至—1bpDNA片段,限制性内切酶MspI酶切的PCR产物,3％琼脂糖凝胶电泳分离酶切后的DNA,确定基因型。结果共检测CHD患者169例(CHD组),健康对照者115例(正常对照组)。两组间基因型及等位基因频率分布差异无显著性意义。总体看基因型不影响血浆apoAI及高密度脂蛋白胆固醇(HDL－C)水平。在cHD伴HDL－c低下的患者中,AA型纯合子例数,尤其是男性患者高于正常对照者(P=0.0028)。结论AA纯合子并伴有HDL－C低下的男性患者患CHD的危险性可能会增加,应予以重视。     

线粒体基因ND_13316G→A突变与2型糖尿病的关系

256例2型糖尿病和140例健康对照者研究显示,线粒体基因ND13316G→A突变在中国北部2型糖尿病人群中的发生率约为3.52%,突变对T2DM的发生有一定风险性,但不是主要的易感基因。     

过氧化物酶体增殖体激活型受体γ(PPARγ)C161→T变异与冠心病关系研究

目的 :探讨过氧化物酶体增殖体激活型受体γ (PPARγ)C1 6 1→T变异与冠心病的关系。　　方法 :本研究采用病例—对照设计 ,筛选 1 50例冠心病患者 (冠心病组 )及 1 57例非冠心病患者 (对照组 )为研究对象。采用聚合酶链式反应—限制性片段多态性方法测定PPARγ基因多态型。　　结果 :冠心病组PARγCT基因型频率显著低于对照组 ( 2 2 7%vs 34 4 % ,P <0 0 5)。各PPARγ基因型之间的体重指数、总胆固醇、低密度脂蛋白胆固醇、高密度脂蛋白胆固醇无显著差异。PPARγCT基因型与体重指数之间存在对冠心病的交互作用 (P =0 0 2 2 )。　　结论 :本研究观察了PPARγC1 6 1→T基因变异在中国人群的分布 ,冠心病患者PPARγCT基因型显著低于对照组。该基因型与体重指数存在对冠心病危险的相互作用。     

Hb L'Aquila [β106(G8)Leu→Val,CTG→GTG]: A Novel Thalassemic Hemoglobin Variant

A new β-globin variant at codon 106 (CTG→GTG), and which we named Hb L'Aquila [β106(G8)Leu→Val], was detected by DNA analysis. The proband and her father presented with the features of a mild β⁺-thalassemia (thal), confirmed by their α/β-globin chain biosynthesis ratios.     

Neonatal Cyanosis Due to a Novel Fetal Hemoglobin: Hb F-Circleville [Gγ63(E7)His→Leu,CAT>CTT]

Neonatal cyanosis can result from a multitude of acquired and inherited causes. Cyanosis resulting from fetal M hemoglobin (Hb) variants is very rare. Only two ^Gγ variants causing methemoglobinemia and cyanosis in the newborn have been reported to date. Here we describe a novel fetal Hb variant, Hb F-Circleville [^Gγ63(E7)His→Leu], associated with methemoglobinemia and cyanosis in the newborn. The patient's sister also had neonatal cyanosis at birth.