广东汉族人TNF多态性

采用PCR-RFLP技术对103例广东汉族人TNF多态性进行了检测,结果是:TNFβ*1纯合子表型频率为0.2524,TNFβ*2纯合子表型频率为0.2913,TNFβ*1/TNFβ*2杂合子表型频率为0.4563,TNFβ*1基因频率0.4806,TNFβ*1基因频率0.5194.本结果与其他人群的结果进行了比较。 Abstract:The sample of 103 Guangdong Han people were determined for TNF by PCR- RFLP methoid,The results are as follows:genotypefrequency:TNFβ* 1/*1 0.2524,TNFβ* 2/*2 0.2913,TNFβ* 1/* 2 0.4563,Genefrequency:TNFβ* 1 0.4806,TNFβ* 2 0.5194.The results of this investigation were compared with that of others population.     

磺酰脲类受体基因多态性与2型糖尿病的相关性研究

研 究磺酰脲类受体1（SUR1）基因外显子16-3c/t多态性在中国某南方汉族人群中是否为2型糖尿病的致病基因座。采用聚合酶链反应-限制酶酶切片段长度多态性（PCR-RFLP）方法对南方汉族46个2型糖尿病高发家系成员的SUR1基因外显子16的多态性进行分析。利用Mantel-Haenszel分层分析研究该基因座多态性与2型糖尿病的关系。在高发家系人群中,SUR1基因外显子16-3c/t多态性的基因型频率为：cc型29.3%、ct型507%、tt型20%,c等位基因频率为54.7%;患者组基因型频率为：cc型30.2% 、ct型53.8%、tt型16.0% ,c等位基因频率为57.1% ;未患病亲属组基因型频率为：cc型28.3% 、ct型47.2%、tt型24.5%,c等位基因频率为519%,两组间基因型和等位基因的差异经检验无统计学意义（分别为χ2=3.224,P=0.199;χ2=1.250,P=0264）。在性别、吸烟、饮酒、肥胖、高血压等混杂因素中的频率差异亦无显著性。c等位基因频率低于北方汉族人。在中国某南方汉族2型糖尿病高发家族人群中,未发现SUR1基因外显子16-3c/t多态性与2型糖尿病存在关联,该基因座可能不是该人群的致病基因。 Abstract:To study whether the 3c/t polymorphism of the sulfonylurea receptor 1 (SUR1) gene exon16 increased the risk of type 2 diabetes mellitus in type 2 diabetes mellitus pedigrees in Han population in south area of China.Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method was used in 46 type 2 diabetes mellitus pedigrees.The polymorphism in SUR1 was tested and analyzed by Mantel-Haenszel χ2 test.Frequencies of SUR1-3c/t polymorphism had no significant difference between type 2 diabetes mellitus and normal relatives（genotypes χ2=3.224,P=0.199;frequency of allele χ2=1.250,P=0.264）.In all subjects,type 2 diabetes mellitus and normal relatives,SUR1-3c/t genotypes were listed (cc:29.3%,30.2%,28.3%;ct:50.7%,53.8%,47.2%;tt:20%,16.0%,24.5% respectively).The frequencies of c were 54.7%,57.1% and 51.9% respectively.The frequency of c is lower than Han population in northern China.The results show that SUR1 exon16-3c/t polymorphism is not associated with type 2 diabetes mellitus in the population.     

中国傣族、景颇族人群中与艾滋病相关的CCR5△32、CCR2b-64I、SDF1-3′A等位基因多态性分布

为了调查HIV-1感染相关的等位基因CCR5△32、CCR2b-64I、SDF1-3′A在我国云南省德宏州傣族景颇族人群中的频率和多态性分布,此课题以101例傣族和113例景颇族人群为研究对象,应用PCR、PCR-RFLP(聚合酶链反应-限制性片段长度多态性)分析方法进行检测,计算突变基因频率;并对其群体分布、性别分布进行统计学分析。结果表明,中国傣族景颇族人群中未发现CCR5△32等位基因突变;傣族CCR2b-64I、SDF1-3′A基因突变频率分别为0.2130和0.2030,景颇族CCR2b-64I和SDF1-3′A基因突变频率分别为0.1637和0.1770;与中国汉族人群相比较,傣族和景颇族中SDF1-3′A突变频率较低（P值分别为0.0322和0.0021）;两个民族的CCR2b-64I和SDF1-3′A等位基因群体分布符合Hardy-Weinberg平衡,在性别之间分布无显著差异。中国傣族景颇族人群的CCR2b-64I等位基因的突变频率与汉族人相似,SDF1-3′A等位基因的突变频率比汉族人低,此两种突变基因在艾滋病发病过程中的影响值得进一步研究。由于未发现CCR5△32基因突变,中国傣族景颇族人群对HIV-1感染可能有较大的遗传易感性。 Abstract:The purpose of the work is to investigate the frequencies and polymorphisms of HIV-1 resistant CCR5delta32,CCR2b-64I,SDF1-3′A alleles in Chinese Dai and Chingpaw populations.Whole blood samples from 101 Dai subjects and 113 Chingpaw were collected randomly and their genomic DNA were extracted with QIAgen Blood Kits.Allelic frequencies were identified by PCR-RFLP analysis.Allelic polymorphisms in Dai population or Chingpaw population and both sexes in the samples were analyzed by χ2 test.The frequencies of CCR5delta32,CCR2b-64I,SDF1-3′A alleles in Dai population were 0.0000,0.2130,0.2030,respectively;The frequencies of CCR5delta32,CCR2b-64I,SDF1-3′A alleles in Chingpaw population were 0.000,0.1637,0.1770,respectively.Distributions of the CCR2b-64I,SDF1-3′A alleles among the both populations were in accordance with Hardy-Weinberg equilibrium.No statistical difference was found in the allelic frequencies of both CCR2b-64I and SDF1-3′A between male and female individuals.The frequencies of CCR5delta32,CCR2b-64I alleles in Chinese Dai and Chingpaw populations are similar to that in Chinese Han population,while the frequency of SDF1-3′A allele in Chinese Dai and Chingpaw populations are lower in contrast to that in Chinese Han population.The genotyping and polymorphism of CCR5delta32,CCR2b-64I,SDF1-3′A alleles in Chinese Dai and Chingpaw populations of Yunnan Province are the first time studied in China.The significance of the three mutant alleles conferring genetic resistance to HIV-1 and AIDS progression remains to be clarified.     

中国傣族、景颇族人群中与艾滋病相关的CCR5△32、CCR2b-64I、SDF1-3′A等位基因多态性分布

为了调查HIV-1感染相关的等位基因CCR5△32、CCR2b-64I、SDF1-3′A在我国云南省德宏州傣族景颇族人群中的频率和多态性分布,此课题以101例傣族和113例景颇族人群为研究对象,应用PCR、PCR-RFLP(聚合酶链反应-限制性片段长度多态性)分析方法进行检测,计算突变基因频率;并对其群体分布、性别分布进行统计学分析。结果表明,中国傣族景颇族人群中未发现CCR5△32等位基因突变;傣族CCR2b-64I、SDF1-3′A基因突变频率分别为0.2130和0.2030,景颇族CCR2b-64I和SDF1-3′A基因突变频率分别为0.1637和0.1770;与中国汉族人群相比较,傣族和景颇族中SDF1-3′A突变频率较低（P值分别为0.0322和0.0021）;两个民族的CCR2b-64I和SDF1-3′A等位基因群体分布符合Hardy-Weinberg平衡,在性别之间分布无显著差异。中国傣族景颇族人群的CCR2b-64I等位基因的突变频率与汉族人相似,SDF1-3′A等位基因的突变频率比汉族人低,此两种突变基因在艾滋病发病过程中的影响值得进一步研究。由于未发现CCR5△32基因突变,中国傣族景颇族人群对HIV-1感染可能有较大的遗传易感性。 Abstract:The purpose of the work is to investigate the frequencies and polymorphisms of HIV-1 resistant CCR5delta32,CCR2b-64I,SDF1-3′A alleles in Chinese Dai and Chingpaw populations.Whole blood samples from 101 Dai subjects and 113 Chingpaw were collected randomly and their genomic DNA were extracted with QIAgen Blood Kits.Allelic frequencies were identified by PCR-RFLP analysis.Allelic polymorphisms in Dai population or Chingpaw population and both sexes in the samples were analyzed by χ2 test.The frequencies of CCR5delta32,CCR2b-64I,SDF1-3′A alleles in Dai population were 0.0000,0.2130,0.2030,respectively;The frequencies of CCR5delta32,CCR2b-64I,SDF1-3′A alleles in Chingpaw population were 0.000,0.1637,0.1770,respectively.Distributions of the CCR2b-64I,SDF1-3′A alleles among the both populations were in accordance with Hardy-Weinberg equilibrium.No statistical difference was found in the allelic frequencies of both CCR2b-64I and SDF1-3′A between male and female individuals.The frequencies of CCR5delta32,CCR2b-64I alleles in Chinese Dai and Chingpaw populations are similar to that in Chinese Han population,while the frequency of SDF1-3′A allele in Chinese Dai and Chingpaw populations are lower in contrast to that in Chinese Han population.The genotyping and polymorphism of CCR5delta32,CCR2b-64I,SDF1-3′A alleles in Chinese Dai and Chingpaw populations of Yunnan Province are the first time studied in China.The significance of the three mutant alleles conferring genetic resistance to HIV-1 and AIDS progression remains to be clarified.     

乙醛脱氢酶2（ALDH2）基因研究进展及其与饮酒行为的关系

亚洲人群中普遍存在突变型的乙醛脱氢酶2（ALDH2*2）。此酶突变后活性缺失,导致乙醛在肝脏内大量累积使突变携带者在喝酒后会有脸红等不适反应,因此这可能影响他们的饮酒行为。由于ALDH2*2等位基因与饮酒行为相关,它也可能与酒精引起的肝脏损伤及某些癌症密切相关,而且,它在不同的亚洲人群中有不同的频率分布。近年来对ALDH2*2等位基因的序列结构、表达及其重要功能等有了更深入的了解,对ALDH2的多态性在研究方法、研究群体分布范围等都有很大进展。本文还讨论了不同地理分布、不同年龄结构、性别差异条件下,中国人群中ALDH2基因型频率与饮酒行为的关系。 Abstract: An atypical allele （ALDH2*2） in low Km aldehyde dehydrogenase (ALDH2), which is highly prevalent in Asian, may influence drinking behavior because of higher production of acetaldehyde in the liver. High alcohol sensitivity such as flushing after drinking has been shown to be mainly due to the atypical ALDH2 genotypes. The atypical allele is associated with alcohol-induced liver injury and some cancers. Recently, the researches on the polymorphisms not only in the gene itself but also its frequencies in different Asian populations have been made great progress. Three factors, including different sex, age and geography, were also analyzed with the genotypes of ALDH2 in Chinese populations.     

乙醇代谢酶基因多态性与酒精性肝病关系

目的:研究乙醇代谢酶基因ADH3、ALDH2及CYP2E1 RsaⅠ/PstⅠ位点多态性与酒精性肝病(ALD)的关系。探讨遗传因素对其易感性的影响。方法:PCR-RFLP法检测东北地区汉族男性健康者、嗜酒者及ALD患者中ADH3、ALDH2和CYP2E1的基因型并比较其基因频率。结果:ADH3和CYP2E1的两种等位基因在各组中的分布差异无统计学意义;ALDH2的两种等位基因在三组间的频率存在统计学差异,ALDH2~*1在嗜酒及ALD组中的频率显著高于其在对照组中的频率,二组均以ALDH2~*1/2~*1基因型为主,未见ALDH2~*2/2~*2;与嗜酒者相比,ALDH2~*2在ALD组中的频率显著提高,且均为ALDH2~*1/2~*2。结论:ADH3及CYP2E1 RsaⅠ/PstⅠ位点多态性与东北地区汉族男性ALD的发生无关;ALDH2~*1是嗜酒的诱因,ALDH2~*2/2~*2可防止嗜酒及ALD的发生,ALDH2~*1/2~*2具有最高的患病风险。     

应用SSP-PCR/SSO方法进行中国辽宁汉族人HLA-DRB1基因的遗传多态性研究

对159名中国辽宁汉族个体的基因组DNA进行分析,共检出42种等位基因,其中以DRB1*09012(12.8%)、*0701(10.7%)、*1501(10.4%) 最为常见,其次为DRB1*1201(7.9%)、*1202(7.5%)、*1101(6.6%)、*0301(5.0%)。并发现辽宁汉族人DRB1等位基因频率与白种人间存在明显差异,揭示不同人种有其自己的主要等位基因。同时对本技术在HLA-DRB1分型应用中的优点进行了讨论。 Abstract　HLA-DRB1 alleles of 159 Chinese donors from Liaoning Han population were determined by using a set of 23 sequence specific oligonucleotide probes directed to various DRB1 alleles. The samples were first amplified and divided into 8 groups by allele/group specific primers. The SSOs enable us to identify 58 different DRB1subtypes. 42 alleles were detected in the study of this population. Among them, the DRB1*09012(12.8%), *0701(10.7%), *1501(10.4%), *1201(7.9%), *1202(7.5%), *1101(6.6%), *0301(5.0%) are the most frequent. The significant difference was found in Chinese northern Han population by comparing the gene frequencies in Caucasoid samples, suggesting that there were principal DRB1 alleles in different races.     

Distribution of HLA class Ⅰ and class Ⅱ haplotypes in Chinese Han population based on family segregation

HLA haplotype analysis has important application value in human population genetics, anthropological research and HLA matching transplantation. Based on HLA-A, -B, -C, -DRB1 and -DQB1 genotyping data from 663 families including 663 leukemia patients and 991 related donors, the allele frequency (AF) and haplotype frequency (HF) of two-, three- and five-locus haplotype distribution patterns in the Chinese Han population were determined by family segregation. A total of 38 alleles at A locus, 75 alleles at B locus, 35 alleles at C locus, 53 alleles at DRB1 locus and 22 alleles at DQB1 locus were discovered in this population. The frequencies of these alleles were basically consistent with those of previous reports except for some tiny differences. The study found 11 A-C, 15 C-B, 4 B-DRB1 and 11 DRB1-DQB1 two-locus haplotypes with a frequency over 2%. The number of A-C-B and A-B-DRB1 three-locus haplotype with a frequency over 1% were 11 and 3 respectively. The most common HLA-A-C-B-DRB1-DQB1 haplotype (HF>1%) were A*3001-C*0602-B*1302-DR*0701-DQ*0202 (4.30%), A*0207-C*0102-B*4601-DR*0901-DQ*0303 (3.07%), A*3303-C*0302-B*5801-DR*0301-DQ*0201 (1.49%) and A*1101-C*0102-B*4601-DR*0901-DQ*0303 (1.01%). The results are helpful for finding matching donors for hematopoietic stem cell transplant patients and also contribute to transplant immunology, HLA-related diseases, research of human genetics and other fields.     

中国南方汉族群体MPSI型Kpn I酶切位点的遗传多态性

为研究中国汉族群体IDUA 基因Kpn I 酶切位点的遗传多态性以及该位点等位基因片段传递的规律, 采用PCR-RFLP技术, 对162例无血缘关系的健康中国汉人的324条 染色体进行检测,另又对5个家系16位成员进行同样的检测,然后用χ2检验进行统计学处理。结果表明,等位基因A1 频率为0.17,等位基因A2 频率为0.83,杂合率为29%;A1 、A2 的传递规律与理论上预计的完全符合。认为中国汉族群体IDUA 基因 Kpn I 酶切位点也具有遗传多态性, 并且与国外报道的无显著性差异;A1、A2 在世代中的传递完全符合孟德尔遗传规律。 Abstract:To investigate the genetic polymorphism of the Kpn I site in the α-L-iduronidase(IDUA) gene from a Han population in southern China and to study the mode of transmission of alleles, PCR-RFLP was used to analyze 324 chromosomes from 162 Chinese unrelated healthy Han individuals, and the analysis of the genotypes of 16 members in five families. To compare the frequencies and heterzygosity between Chinese Han population and Caucasians in Western by using χ2test. The frequency of allele 1 (450bp) was 0.17,allele 2 (390 plus 60 bp) 0.83, the heterozygosity was 29%.The genotypes of each member of all families detected was completely agreement with the theorical assessment. The locus of Kpn I in the IDUAgene from Han population has polymorphism. There is no significant difference between Chinese Han population and Caucasians in Western countries. The transmission of alleles was agreement with the Mendelian genetic law.     

中国汉蒙两族人群MTHFR基因热敏感性多态性分布的比较

为比较中国蒙汉两族人群MTHFR基因第677位核苷酸多态性的分布情况,获得该位点多态性的群体遗传学数据,本研究应用PCR扩增技术, 其扩增产物用限制性核酸内切酶Hinf I消化后进行非变性聚丙烯酰胺凝胶电泳,分析蒙汉族人群中MTHFR基因第677位核苷酸基因型（野生型、杂合型和突变纯合型）的分布频率。结果表明,蒙族人群基因型构成以野生型为主,占45.6％,突变杂合型占39.2％,突变纯合型仅占15.2％,汉族人群基因型构成以突变杂合型为主,占55.7％,野生型仅占17.9％,突变纯合型占26.4％,明显高于蒙族人群。经χ2检验,两组基因型构成比具有显著性差异（P<0.001）;蒙族人群MTHFR 677T等位基因频率为34.8％,经u检验显著低于汉族人群（54.2％）的频率。据此认为,中国蒙族人群MTHFR热敏感性基因突变频率显著低于汉族人群,提示该基因多态性分布在中国不同民族人群中存在差异。 Abstract：The purpose of this study is to compare the genetic polymorphism distribution of the 677th nucleotide of MTHFR between the Mongolian population and the Hans of China,and to obtain the population genetic data of this polymorphism.Using PCR－RFLP method,the authors analyzed the genotypes of the 677th nucleotide of MTHFR in Mongolians and Hans.Results show that in Mongolian population,the proportion of wild type is 45.6％,proportion of heterozygotes is 39.2％ and that of homozygotes is 15.2％; While in Hans,proportions are wild type 17.9％,heterozygotes 55.7％ and homozygotes 26.4％.The ratios of genotypes are significantly different between Mongolian and Han populations(χ2－test,P<0.001).The 677th allele frequency in Mongolians is 34.8％,lower than that in Hans(54.2％,u－test,P<0.001).This suggests that the mutant MTHFR gene frequency is significantly higher in the Han population than in the Mongolian population in China.     

Alcohol and aldehyde dehydrogenase genotypes and alcoholism in Chinese men.

The liver enzymes alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH), which are responsible for the oxidative metabolism of ethanol, are polymorphic in humans. An allele encoding an inactive form of the mitochondrial ALDH2 is known to reduce the likelihood of alcoholism in Japanese. We hypothesized that the polymorphisms of both ALDH and ADH modify the predisposition to development of alcoholism. Therefore, we determined the genotypes of the ADH2, ADH3, and ALDH2 loci of alcoholic and nonalcoholic Chinese men living in Taiwan, using leukocyte DNA amplified by the PCR and allele-specific oligonucleotides. The alcoholics had significantly lower frequencies of the ADH2*2, ADH3*1, and ALDH2*2 alleles than did the nonalcoholics, suggesting that genetic variation in both ADH and ALDH, by modulating the rate of metabolism of ethanol and acetaldehyde, influences drinking behavior and the risk of developing alcoholism.     

Interaction between the functional polymorphisms of the alcohol-metabolism genes in protection against alcoholism.

The genes that encode the major enzymes of alcohol metabolism, alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH), exhibit functional polymorphism. The variant alleles ADH2*2 and ADH3*1, which encode high-activity ADH isoforms, and the ALDH2*2 allele, which encodes the low-activity form of ALDH2, protect against alcoholism in East Asians. To investigate possible interactions among these protective genes, we genotyped 340 alcoholic and 545 control Han Chinese living in Taiwan at the ADH2, ADH3, and ALDH2 loci. After the influence of ALDH2*2 was controlled for, multiple logistic regression analysis indicated that allelic variation at ADH3 exerts no significant effect on the risk of alcoholism. This can be accounted for by linkage disequlibrium between ADH3*1 and ADH2*2 ALDH2*2 homozygosity, regardless of the ADH2 genotypes, was fully protective against alcoholism; no individual showing such homozygosity was found among the alcoholics. Logistic regression analyses of the remaining six combinatorial genotypes of the polymorphic ADH2 and ALDH2 loci indicated that individuals carrying one or two copies of ADH2*2 and a single copy of ALDH2*2 had the lowest risk (ORs 0.04-0.05) for alcoholism, as compared with the ADH2*1/*1 and ALDH2*1/*1 genotype. The disease risk associated with the ADH2*2/*2-ALDH2*1/*1 genotype appeared to be about half of that associated with the ADH2*1/*2-ALDH2*1/*1 genotype. The results suggest that protection afforded by the ADH2*2 allele may be independent of that afforded by ALDH2*2.     

Polymorphisms of alcohol metabolizing enzyme and cytochrome P4502E1 genes in mongolian population

Although the genetic polymorphism of the alcohol-metabolizing enzymes was extensively studied at the molecular level by many investigators, the genetic polymorphism studies for ethanolmetabolizing enzymes in Mongolians are very rare. The present study was therefore performed to determine the genetic distribution of various forms of alcohol-metabolizing enzymes such as alcohol dehydrogenase 2 (ADH2, currently accepted nomenclature ADH1B), ADH3 (ADH1C), aldehyde dehydrogenase 2 (ALDH2) and cytochrome P4502E1 (CYP2E1) in 300 healthy Mongolian males. Genetic polymorphisms were determined by polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP) methods. The allele frequencies ofADH2 *1 andADH2 *2 were 0.24 and 0.76;ADH3 *1 andADH3 *2 were 0.92 and 0.08;ALDH2 *1 andALDH2 *2 were 0.96 and 0.04; andCYP2E1 *C andCYP2E1 *D were 0.15 and 0.85, respectively. Compared to the results reported by other investigators, the allele frequencies ofALDH2 *2 andCYP2E1 *C among Mongolian subjects were much lower than among East Asians (Korean, Japanese, and/or Han-Chinese), while those ofADH2 andADH3 were more similar. Interestingly, this study shows that the ineffectiveALDH2 gene (ALDH2*2 allele) among Mongolians is not as common as among East Asians.     

Genotoxic effects of alcohol in human peripheral lymphocytes modulated by ADH1B and ALDH2 gene polymorphisms

Ethanol is almost totally broken down by oxidative metabolism in vivo. Ethanol per se is considered to be neither carcinogenic, mutagenic nor genotoxic. However, during the metabolic conversion of ethanol to acetaldehyde and acetate, the organism is exposed to both ethanol and acetaldehyde and therefore ethanol is suspected to be co-carcinogenic. The genetic polymorphisms of alcohol dehydrogenase-2 (ADH1B) and acetaldehyde dehydrogenase-2 (ALDH2) influence the metabolism of alcohol. The ADH1B*1/*1 genotype encodes the low-activity form of ADH1B, and ALDH2*1/*2 and ALDH2*2/*2 genotype encode inactive ALDH2. The aim of this study was to test the hypothesis that polymorphisms of the ADH1B and ALDH2 genes are significantly associated with genotoxicity induced by alcohol drinking, measured using the cytokinesis-block micronucleus (CBMN) assay, an established biomarker of genome instability, in peripheral blood lymphocytes of 286 healthy Japanese men. There was a significant trend for the mean micronuclei (MN) frequency in habitual or moderate drinkers without a smoking habit to increase as the numbers of the *1 allele in ADH1B increased (P=0.039 or P=0.029) and the *2 allele in ALDH2 increased (P=0.019 or P=0.037). A logistic regression analysis showed that the number of subjects with MN frequency levels more than median value of MN (3.0) was significantly higher in the subjects with the ADH1B*1 allele as adjusted estimates (OR 2.08, 95% C.I. 1.24-3.48), when the OR for the subjects with the ADH1B*2/*2 genotype was defined as 1.00. The number of subjects with MN frequency levels more than median value of MN was also significantly higher in the subjects with the ALDH2*2 allele as adjusted estimates (OR 1.79, 95% C.I. 1.04-3.11), when the OR for the subjects with the ALDH2*1/*1 genotype was defined as 1.00. The results of this study have identified important novel associations between ADH1B/ALDH2 polymorphisms and genotoxicity in alcohol drinkers.     

Gene-environmental interactions between alcohol-drinking behavior and ALDH2 and CYP2E1 polymorphisms and their impact on micronuclei frequency in human lymphocytes

Ethanol is converted to acetaldehyde by alcohol dehydrogenase (ADH), cytochrome p4502E1 (CYP2E1) and catalase. This metabolite is then detoxified by aldehyde dehydrogenase 2 (ALDH2), a key enzyme in the elimination of acetaldehyde, via further oxidation to acetic acid. The toxic effects of acetaldehyde are well documented and may be partially mediated by genotoxic damage. In the present study, we investigated the effects of alcohol-drinking behavior and genetic polymorphisms in two different genes (ALDH2 and CYP2E1) on the micronuclei (MN) frequency in 248 healthy Japanese men. Genotyping was performed by PCR-RFLP analysis. The ALDH2 variant (deficient type) was significantly associated with an increased MN frequency in subjects drinking more than three times/wk, while habitual drinkers with wild-type CYP2E1 also had a significantly increased MN frequency. Furthermore, when the subjects were divided into eight groups according to their drinking frequency and genotypes of ALDH2 and CYP2E1, we found that habitual drinkers with homozygous CYP2E1*1/*1 and heterozygous ALDH2*1/*2 or homozygous ALDH2*2/*2 showed the highest mean MN frequency. In the present study, we found clear associations among ALDH2 and CYP2E1 gene polymorphisms, alcohol-drinking behavior and genotoxic effects in a healthy Japanese population. Therefore, analysis of the polymorphisms of alcohol-metabolizing enzymes may lead to elucidation of the mechanism(s) for individual susceptibilities to the toxicity of ethanol metabolites.     

Characterization of variant alleles of cytochrome CYP2D6 in a Spanish population

The CYP2D6 gene codes for a P450 monooxygenase which is involved in the biotransformation of a large number of commonly prescribed drugs. Adverse drug effects and therapeutic failure can be related to abnormal CYP2D6 activity. We investigated the allele and genotype frequencies of cytochrome P4502D6 in a Spanish population to predict the prevalence of ultra-rapid and poor metabolizer phenotypes in our population and to design a feasible CYP2D6 genotyping protocol. The study included 105 healthy unrelated Spanish Caucasian volunteers. CYP2D6 genotyping was performed by a combination of long-PCR, direct sequencing and allele-specific real-time PCR. The frequency of the wild-type CYP2D6*1 allele was 31%. The alleles coding for slightly (CYP2D6*2) or moderately (*9 and *10) reduced activity showed frequencies of 40.47, 2.38 and 1.90%, respectively. Frequencies of defective alleles *3, *4, *5 and *6 were 0.95, 13.8, 3.33 and 0.95%, respectively. The defective CYP2D6 alleles *7, *8, *12, *14, *15 and *21 were not found. Duplicated CYP2D6 alleles were detected at a frequency of 4.27%. Our protocol allows the identification of the four inactive CYP2D6 alleles (*3, *4, *5 and *6) and the detection of alleles with CYP2D6 *1, CYP2D6 *2 and CYP2D6*4 gene duplications. Testing for this reduced CYP2D6 allele set would facilitate its use in clinical practice by assisting in the development of individualized pharmacotherapy.     

Polymorphisms of ethanol-oxidizing enzymes in alcoholics with inactive ALDH2

Inactive aldehyde dehydrogenase-2 (ALDH2) is a well-known biological deterrent of heavy drinking among Asians, although some individuals who have inactive ALDH2 do become alcoholics. Unknown biological mechanisms facilitating the development of the disease may operate in such a way that these individuals overcome adverse reactions, or they may lower the intensity of the reactions. To examine our hypothesis that ethanol-oxidizing isoenzymes have lower catalytic properties in some persons, we investigated polymorphisms of ethanol-oxidizing enzymes that may alter their catalytic activities, viz., alcohol dehydrogenase-2 (ADH2) and –3 (ADH3), and cytochrome P450 2E1 (CYTP2E1), among 80 Japanese alcoholics with inactive ALDH2, 575 alcoholics with active ALDH2, and 461 controls. Although higher ADH2*1 and ADH3*2 allele frequencies were observed in alcoholics than in controls, there was no significant difference in ADH2 and ADH3 genotypes between alcoholics with inactive ALDH2 and alcoholics with active ALDH2. The genotype distributions of CYTP2E1 did not differ among the three groups, indicating no allelic association of the c1/c2 polymorphism of CYTP2E1 with alcoholism. These results suggest that genetic variations in ethanol-oxidizing activities are involved in the development of the disease, but that these variations are not specific in alcoholics with inactive ALDH2, a group at genetically low risk for alcoholism.     

Acetaldehyde as an underestimated risk factor for cancer development: role of genetics in ethanol metabolism

Chronic ethanol consumption is a strong risk factor for the development of certain types of cancer including those of the upper aerodigestive tract, the liver, the large intestine and the female breast. Multiple mechanisms are involved in alcohol-mediated carcinogenesis. Among those the action of acetaldehyde (AA), the first metabolite of ethanol oxidation is of particular interest. AA is toxic, mutagenic and carcinogenic in animal experiments. AA binds to DNA and forms carcinogenic adducts. Direct evidence of the role of AA in alcohol-associated carcinogenesis derived from genetic linkage studies in alcoholics. Polymorphisms or mutations of genes coding for AA generation or detoxifying enzymes resulting in elevated AA concentrations are associated with increased cancer risk. Approximately 40% of Japanese, Koreans or Chinese carry the AA dehydrogenase 2*2 (ALDH2*2) allele in its heterozygous form. This allele codes for an ALDH2 enzyme with little activity leading to high AA concentrations after the consumption of even small amounts of alcohol. When individuals with this allele consume ethanol chronically, a significant increased risk for upper alimentary tract and colorectal cancer is noted. In Caucasians, alcohol dehydrogenase 1C*1 (ADH1C*1) allele encodes for an ADH isoenzyme which produces 2.5 times more AA than the corresponding allele ADH1C*2. In studies with moderate to high alcohol intake, ADH1C*1 allele frequency and rate of homozygosity was found to be significantly associated with an increased risk for cancer of the upper aerodigestive tract, the liver, the colon and the female breast. These studies underline the important role of acetaldehyde in ethanol-mediated carcinogenesis.     

Acetaldehyde dehydrogenase 2 SNP rs671 and susceptibility to essential hypertension in Mongolians: a case control study

Mongolians are known as heavy drinkers, and they have a high incidence of essential hypertension, which may be an associated pathology. We examined a possible association of essential hypertension and polymorphism of the aldehyde dehydrogenase 2 (ALDH2) gene in Mongolians from Inner Mongolia. Single nucleotide polymorphism rs671 of ALDH2 was detected by TaqMan PCR in 91 essential hypertensive patients (44 males and 47 females) and 70 healthy Mongolians (37 males and 33 females). Frequencies of the ALDH2*1/1 genotype and the ALDH2*1 allele in patients (91.2 and 95.6%, respectively) were significantly higher than in controls (78.6 and 89.3%; P < 0.05), while frequencies of ALDH2*1/2 genotype and ALDH2*2 allele in patients (8.79 and 4.4%) were much lower than in controls (21.4 and 10.7%; P < 0.05). Frequencies of ALDH2*1/1 genotype and ALDH2*1 allele in female patients (95.8 and 94.9%) were higher than in female controls (70.0 and 84.9%; P < 0.05); frequencies of the ALDH2*1/2 genotype and the ALDH2*2 allele in female patients (4.25 and 2.13%) were lower than in female controls (30.3 and 15.2%, P < 0.05). There was no significant difference in male subjects. ALDH2*2/2 was not found in any of the subjects. We conclude that ALDH2 polymorphism is associated with essential hypertension in Mongolians, especially in female Mongolians. ALDH2*2 was found to be a negative risk factor for essential hypertension in Mongolians from Inner Mongolia.     

Alcohol Dehydrogenase-1B (rs1229984) and Aldehyde Dehydrogenase-2 (rs671) Genotypes Are Strong Determinants of the Serum Triglyceride and Cholesterol Levels of Japanese Alcoholic Men

Background

Elevated serum triglyceride (TG) and high-density-lipoprotein cholesterol (HDL-C) levels are common in drinkers. The fast-metabolizing alcohol dehydrogenase-1B encoded by the ADH1B*2 allele (vs. ADH1B*1/*1 genotype) and inactive aldehyde dehydrogenase-2 encoded by the ALDH2*2 allele (vs. ALDH2*1/*1 genotype) modify ethanol metabolism and are prevalent (≈90% and ≈40%, respectively) in East Asians. We attempted to evaluate the associations between the ADH1B and ALDH2 genotypes and lipid levels in alcoholics.

Methods

The population consisted of 1806 Japanese alcoholic men (≥40 years) who had undergone ADH1B and ALDH2 genotyping and whose serum TG, total cholesterol, and HDL-C levels in the fasting state had been measured within 3 days after admission.

Results

High serum levels of TG (≥150 mg/dl), HDL-C (>80 mg/dl), and low-density-lipoprotein cholesterol (LDL-C calculated by the Friedewald formula ≥140 mg/dl) were observed in 24.3%, 16.8%, and 15.6%, respectively, of the subjects. Diabetes, cirrhosis, smoking, and body mass index (BMI) affected the serum lipid levels. Multivariate analysis revealed that the presence of the ADH1B*2 allele and the active ALDH2*1/*1 genotype increased the odds ratio (OR; 95% confidence interval) for a high TG level (2.22 [1.67–2.94] and 1.39 [0.99–1.96], respectively), and decreased the OR for a high HDL-C level (0.37 [0.28–0.49] and 0.51 [0.37–0.69], respectively). The presence of the ADH1B*2 allele decreased the OR for a high LDL-C level (0.60 [0.45–0.80]). The ADH1B*2 plus ALDH2*1/*1 combination yielded the highest ORs for high TG levels and lowest OR for a high HDL-C level. The genotype effects were more prominent in relation to the higher levels of TG (≥220 mg/dl) and HDL-C (≥100 mg/dl).

Conclusions

The fast-metabolizing ADH1B and active ALDH2, and especially a combination of the two were strongly associated with higher serum TG levels and lower serum HDL-C levels of alcoholics. The fast-metabolizing ADH1B was associated with lower serum LDL-C levels.