CCR5del32 Homozygous deletion in the chemokine receptor R5 gene provides almost complete protection to individuals against HIV infection. However, data relating to the protective effect for CCR5del32 heterozygous individuals have been contradictory. The frequency of the CCR5del32 allele in population control cohorts was compared with that of a group of children (27 Kalmyks and 50 Russians) infected by G-subtype HIV-1 in a nosocomial outbreak. The frequency of the CCR5del32 allele was shown to be lower among the infected children in comparison with that of the control group; however, the difference was small and statistically insignificant. Similar results were obtained in a number of earlier studies. The insignificance of the small differences could be a result of one of two reasons. (i) The fact that there is no protective effect of the heterozygous state, and that the phenomenon depends only on the fluctuation of allele frequencies. In this case, there would be no differences even if the infected cohort is enlarged. (ii)The protective effect of the heterozygous state is real; however, the size of the studied cohort is insufficient to demonstrate it. In order to discern between these two reasons, a meta-analysis of data from 25 published articles (a total of 5,963 HIV-infected individuals and 5,048 individuals in the control group, including the authors' own data) was undertaken. A conclusion was drawn from the meta-analysis that the CCR5del32 allele protects individuals against the HIV infection even in a heterozygous state (OR=1.22, 95%CI=1.10-1.36). The risk of HIV infection for CCR5 wt/del32 heterozygotes was lower by at least 13% as compared to that for wild type CCR5 wt/wt homozygotes. Prior to this study, no data of the type or any conclusions had been published for Caucasians. The mortality rate in the 15 years following the infection was found to be approximately 40% lower for CCR5del32 heterozygotes in comparison with that for the wild type homozygotes in the studied group. The size of the studied group was insufficient to claim difference validity (OR=2.0; p=0.705), even though the effect quantitatively matched the published data. The features of the meta-analysis influencing the threshold level and the statistical validity of the effects are being discussed. The level of the CCR5del32 protective effect on the chances to be infected with HIV and on the outcome of the HIV infection was assessed for various ethnic groups.
Tuberculosis (TB) is one of the most important concerns of public health. There is evidence suggesting that genetic status is responsible for predisposition to infectious diseases including TB. To determine genetic risk factors of TB development, the frequencies of polymorphisms of genes CYP1A1, CYP2D6, CYP2C9, CYP2C19, GSTT1, GSTM1, NAT2, MDR1, and NRAMP1 in 73 TB patients and 352 healthy individuals were determined by allele-specific hybridizatio n using microarray technology. The TB patients have shown a significant increase in the frequency of the null GSTT1 genotype (OR = 3.26, 95% CI = 1.91–5.55, p = 0.000028) as well as the double null GSTT1/GSTM1 genotype (OR = 4.05, 95% CI = 2.14-7.65,p = 0.000034) compared to the group of healthy donors. It was shown that the NAT2* 5/* 5 genotype in combination with the “null” GSTT1 and the double “null” GSTT1/GSTM1 genotypes was observed significantly more often in the TB patients than in the control sample. Thus the examined GSTT1, GSTM1 and NAT2 gene polymorphisms may potentially alter the risk of TB development in ethnic Russians and are of interest for further research using larger cohorts of patients.
Polymorphism of Biotransformation Genes and Risk of Relapse in Childhood Acute LeukemiaLeukemia is a hematological malignancy that involves bone marrow. Polymorphism of biotransformation genes plays an important role in primary childhood leukemia and affects the incidence and character of acute leukemia relapse. A biochip designed to assess some polymorphisms of biotransformation genes was used to determine the frequency of the polymorphic variants ofCYP1A1, CYP2D6, GSTT1, GSTM1, MTHFR, MTRR, NQO1, CYP2C9, CYP2C19andNAT2in 332 children with acute lymphoblastic leukemia (ALL) and 71 children with acute myeloblastic leukemia (AML). TheCYP1A1 *1/*2A, GSTT1non null andGSTM1non null genotypes were more frequent in patients with primary leukemia than in relapse. Analysis of theNAT2genotype frequency revealed a characteristic genotype for each type of leukemia, which prevailed in patients with relapse: the genotype341C/-, 481T/-, 590G/G, 857G/Gprevailed in ALL patients with relapse, and the genotype341T/T, 481C/C, 590A/- in AML patients with relapse when compared with patients having primary ALL or AML, respectively. Thus, the polymorphisms ofCYP1A1, GSTT1, GSTM1andNAT2genes can be considered as markers for risk of relapse in childhood acute leukemia and can be used for the prognosis and individualization of standard therapy.
N-acetyltransferase 2 (NAT2) is a key enzyme of biotransformation phase II that metabolizes genotoxic compounds such as carcinogens and mutagens in different types of cells. A decreased NAT2 activity may correlate with sensitivity to harmful environmental factors, thus increasing susceptibility to different multifactorial diseases, including dermatologic conditions like psoriasis. A biochip developed in our lab to detect 17 NAT2 SNPs was tested on 279 clinical DNA samples from 180 patients with psoriasis and 99 healthy individuals, all residents of Moscow. Six polymorphisms that are most common in European populations (282C > T, 341T > C, 481C > T, 590G > A, 803A > G, and 857G > A) were detected. The NAT2 allele and genotype frequencies for individual SNPs did not differ between patients and healthy individuals. The frequency of the slow acetylation phenotype was increased in patients with type II psoriasis and in normosthenic patients as compared to controls (OR = 1.76, P = 0.177 and OR = 2.07, P = 0.050, respectively). Genotype 341C/C,481T/T,803G/G was significantly more frequent in patients who smoked at least one pack of cigarettes per day and in those who regularly consumed alcohol than in controls (OR = 7.42, P = 0.008 and OR = 106.11, P = 0.003, respectively). The frequency of genotype 341T/T, 481C/C, 590A/-, 803A/A was increased in patients with adverse reactions to medications (OR = 2.05, P = 0.099). Thus, our data suggest that some NAT2 genotypes in combination with certain lifestyles can be considered risk factors of psoriasis in the Moscow population.
Background. Polymorphisrns that reduce the activity of thiopurine S-methyltransferase (TPMT) Cause adverse reactions to conventional closes of thiopurines, routinely used for antileukemic and immunosuppressive treatment. There are more than 20 variant alleles of TPMT that Cause decreased enzymatic activity. We Studied the most common variant alleles of TPMT and their frequency distribution in a large cohort Of Multiracial residents in the Russian Federation and Compared their frequencies in children with and Without malignancy to determine whether TPMT gene abnormality is associated with hematologic malignancy. Procedure. The TPMT biochip was used to detect 6 TPMT single nucleotide polymorphisms (SNPs) corresponding to 7 TPMT-deficiency alleles (TPMT*2, TPMT*3A, TPMT-3B, TPAIT-3C, TPA4T*3D, TPMT*7, and TPMT*8). We analyzed allele frequencies in the whole cohort, the childhood cancer group, and the non-cancer group. We also characterized disease features and Outcome according to the presence of TPMT SNP's in children With acute lymphoblastic leukemia (ALL). Results. Fifty-five (5.5%) study participants overall had heterozygous TPMT genotypes (1 variant and 1 wild-type allele): TPA17'*1/*3A (n=45; 4.5%), TPMT*1/*31C (n = 8; 0.8%), and TPMT*1/*2 (n = 2; 0.2%). TPMT SNP's were more frequent in children with hematologic malignancy than in other participants (7.5% vs. 4.0%, P=0.02). We found no significant association between TPMT SNPs and ALL treatment Outcome (median follow-up, 31.3 months). Conclusions. TPMT*3A is the most prevalent variant allele in the Russian Federation. The estimated frequency of variant alleles in the study cohort (5.5%) was similar to that observed in the White Populations in the U.S. and Eastern Europe. Pediatr Blood Cancer 2009;52:203-208. (C) 2008 Wiley-Liss, Inc.
Ruacetyltransferase 2 (NAT2) is one of key enzymes of the second phase of biotransformation that metabolize genotoxic compounds such as carcinogens and mutagens in different types of cells. There is a correlation between the decreasing activity of NAT2 gene product and the sensitivity to harmful environmental factors that increase the risk of occurrence of different multifactorial diseases, including dermatological ones like psoriasis. We developed the NAT2-biochip for 17 SNPs. The biochip was been tested on 279 clinical DNA samples from 180 patients with psoriasis and 99 healthy individuals, residents of Moscow. We found only six SNPs that were significant for European populations (282C > T, 341T > C, 481C > T, 590G > A, 803A > G and 857G > A). The analysis in psoriasis group did not show any genotype association. The increase in frequency of a slow acetylation phenotype in group of patients with type II psoriasis and in group of patients with normosthenic constitution, in comparison with control group (OR = 1.76,p = 0.177 and OR = 2.07,p = 0.050, respectively) has been revealed. The results for patients smoking one or more pack of cigarettes per day, and daily alcohol drinking in comparison with the control showed an increase in frequency for the genotype 341C/C, 481T/T, 803G/G (OR = 7.42, p = 0.008 and OR = 106.11, p = 0.003, respectively). We also found an increase of frequency of genotype 341T/T, 481C/C, 590A/-, 803A/A in patients with side reactions to medical products comparing with group of healthy donors (OR = 2.05, p = 0.099). Thus, the present data show that the certain NAT2 genotypes and some styles of life can be considered as risk factors of psoriasis development in this muscovite population.
Продукт гена NAT2 (N-ацетилтрансфераза 2) участвует в биотрансформации и детоксикации ряда ароматических аминов (в частности, 2-аминофлуорена, 4-аминобифенила и 4-нафтиламина), которые являются сильными мутагенами и канцерогенами, а также влияет на метаболизм лекарственных препаратов, ацетилируемых этим ферментом. Разработан биологический микрочип для обнаружения 16 точечных мутаций гена NAT2, сочетания которых определяют 36 аллелей и 660 генотипов гена NAT2. Эти генотипы можно разделить на четыре группы по фенотипу ацетилирования: фенотип “быстрого” (R/R), “промежуточного” (R/S), “медленного” (S/S) ацетилирования и группа, в которой могут быть аллели с фенотипом как промежуточного, так и медленного ацетилирования (R/S или S/S). Группа “R/S или S/S” включает аллели, определяемые сочетанием 7 мутаций (191G/A, 282C/T, 341T/C, 481C/T, 590G/A, 803A/G, 857G/A), цис-транс-положение которых можно установить с помощью рестрикционного анализа. Однозначно определен NAT2-генотип 37 из 71 образца ДНК, а 34 образца охарактеризованы более чем двумя генотипами. По фенотипу ацетилирования в группу “R/S или S/S” из этих 34 образцов ДНК вошли 16, содержащих шесть мутаций: 282C/T, 341T/C, 481C/T, 590G/A и 803A/G. Таким образом, данный биочип позволяет проводить первичный анализ большинства полиморфных замен в гене NAT2.
The product of gene NAT2 (N-acetyltransferase 2) is involved in the biotransformation system and participates in detoxication of some arylamine derivatives (in particular 2-aminofluorene, 4-aminobiphenyl and 4-naphthylamine) which are strongly mutagenic and carcinogenic. It also renders toxicological and pharmacological influence on a metabolism of medical products metabolized by the enzyme. We developed a microchip for detection of 16 functionally significant mutations coding 36 alleles of gene NAT2. Combinations of these alleles allow us to reveal more than 660 genotypes, which can be divided into four groups according acetylation phenotype: "fast" (R/R), "intermediate" (R/S), "slow" (S/S) and group with average or slow acetylating (R/S or S/S) alleles. The groups "R/S or S/S" include alleles, formed by a combination of 7 mutations (191G/A, 282C/T, 341T/C, 481C/T, 590G/A, 803A/G, 857G/A), theirs cis-trans position can be revealed by restriction analysis. In 37 of 71 DNA samples we unequivocally defined NAT2-genotypes, and other 34 samples have been characterized by more than two genotypes. 16 samples out of 34 had acetylation phenotype of group "R/S or S/S", which is characterized by the following combination of mutations: 282C/T, 341T/C, 481C/T, 590G/A and 803A/G. Thus, the developed biochip is a convenient screening method for primary detection of the majority of polymorphic replacements in gene NAT2.
В 16 популяциях, представляющих 12 этнических групп (всего 1103 индивида) России и сопредельных стран, установлены частоты аллелей и генотипов гена аполипопротеина Е (APOE), участвующего в регуляции липидного обмена. Частоты аллеля 4, являющегося фактором риска болезни Альцгеймера и ишемической болезни сердца, варьируют в исследованных группах от менее 5 до более 20%, а мажорного аллеля 3 от менее 75 до 95%. Частоты аллелей 3 и 4 составили 0.714 и 0.205 у саамов, 0.735 и 0.220 у коми-ижемцев, 0.770 и 0.130 у коми-зырян, 0.771 и 0.149 у удмуртов, 0.734 и 0.149 у мари, 0.841 и 0.122 у эвенков, 0.788 и 0.163 у бурят, 0.764 и 0.202 у чукчей, 0.875 и 0.075 у иранцев, 0.956 и 0.044 у горцев Памира, 0.771 и 0.094 у украинцев, 0.795 и 0.091 у белорусов. У русских разных регионов частоты этих аллелей составили 0.728 и 0.139 (Кострома), 0.795 и 0.105 (Москва), 0.857 и 0.092 (Ростов-на-Дону), 0.824 и 0.083 (Краснодар) соответственно. Показано, что частоты аллелей 3 и 4 гена APOE в исследованных популяциях имеют широтное распределение, соответствующее градиенту частот этих аллелей в популяциях Евразии.
The NAT2 product, N-acetyltransferase 2, is involved in biotransformation and detoxification of several aromatic amines (in particular, 2-aminofluorene, 4-aminobiphenyl, and 4-naphthylamine), which are strongly mutagenic and carcinogenic, and acetylates some drugs, affecting their metabolism. A biological microchip was developed to detect 16 point mutations, which determine 36 alleles and 660 genotypes of NAT2. The genotypes can be divided into four groups according to the acetylator phenotype: groups with rapid (R/R), intermediate (R/S), or slow (S/S) acetylation and a group combining intermediate and slow alleles ("R/S or S/S"). The last group includes the alleles determined by combinations of seven mutations (191G/A, 282C/T, 341T/C, 481C/T, 590G/A, 803A/G, and 857G/A), whose cis or trans position is detectable by restriction enzyme analysis. The NAT2 genotype was unequivocally established for 37 out of 71 DNA specimens, while the other 34 specimens were characterized by more than two genotypes. By the acetylator phenotype, 16 out of the 34 genotypes were assigned to the group "R/S or S/S," combining mutations 282C/T, 341T/C, 481C/T, 590G/A, and 803A/G. Thus, the biochip allows primary analysis of most NAT2 polymorphic substitutions, the acetylator genotype being important to know in predictive medicine and individualized therapy.
Allele and genotype frequencies for the locus encoding apolipoprotein E, involved in the regulation of lipid metabolism (APOE), were evaluated in 16 populations representing 12 ethnic groups (a total of 1103 subjects) from Russia and neighboring countries. In the populations examined, the frequencies of allele ɛ4, which is the risk factor of Alzheimer’s disease and coronary heart disease, varied from less than 5 to more than 20%, while the variation of the major ɛ3 allele in these populations ranged from less than 75 to 95%. The frequencies of alleles ɛ3 and ɛ4 were 0.714 and 0.205 in Saami, 0.735 and 0.220 in Komi-Izhemts, 0.770 and 0.130 in Komi-Zyryans, 0.771 and 0.149 in Udmurts, 0.734 and 0.149 in Maris, 0.841 and 0.122 in Evenks, 0.788 and 0.163 in Buryats, 0.764 and 0.202 in Chukchi, 0.875 and 0.075 in Iranians, 0.956 and 0.044 in mountain-dwellers of the Pamirs, 0.771 and 0.094 in Ukrainians, and 0.795 and 0.091 in Belarussians, respectively. In Russians from different regions of the country, the frequencies of these alleles were 0.728 and 0.139 (Kostroma), 0.795 and 0.105 (Moscow), 0.857 and 0.092 (Rostov-on-Don), and 0.824 and 0.083 (Krasnodar), respectively. The latitudinal distribution of the APOE ɛ3 and ɛ4 allele frequencies in the populations examined was comparable to the frequency distribution pattern of these alleles in other populations of Eurasia.
The N-acetylation polymorphisms of volunteers from the Moscow population analyzed by phenotyping and genotyping have been compared. The ratios between the proportions of fast acetylators (FAs) and slow acetylators (SAs) estimated by phenotyping and genotyping do not differ significantly from each other (47 and 44%, respectively). The absolute acetylation rate widely varies in both FAs and SAs. The NAT2 genotype and allele frequencies in the population sample have been calculated. The most frequent alleles are NAT2*4 (a "fast" allele), NAT2*5, and NAT2*6 ("slow" alleles); the most frequent genotypes are NAT2*5/*5, NAT2*4/*6, and NAT2*4/*5. Comparative analysis of N-acetylation polymorphism estimated by phenotyping and genotyping in the same subjects has shown a complete concordance between the phenotype and genotype in only 62 out of 75 subjects (87%). Comparative characteristics and presumed applications of the two approaches (quantitative estimation of acetylation rate and qualitative determination of the acetylator genotype) to the identification of individual acetylation status are presented.
Y chromosomes from representative sample of Eastern Ukrainians (94 individuals) were analyzed for composition and frequencies of haplogroups, defined by 11 biallelic loci located in non-recombining part of the chromosome (SRY1532, YAP, 92R7, DYF155S2, 12f2, Tat, M9, M17, M25, M89, and M56). In the Ukrainian gene, pool six haplogroups were revealed: E, F (including G and I), J, N3, P, and R1a1. These haplogroups were earlier detected in a study of Y-chromosome diversity on the territory of Europe as a whole. The major haplogroup in the Ukrainian gene pool, haplogroup R1a1 (earlier designated HG3), accounted for about 44% of all Y chromosomes in the sample examined. This haplogroup is thought to mark the migration patterns of the early Indo-Europeans and is associated with the distribution of the Kurgan archaeological culture. The second major haplogroup is haplogroup F (21.3%), which is a combination of the lineages differing by the time of appearance. Haplogroup P found with the frequency of 9.6%, represents the genetic contribution of the population originating from the ancient autochthonous population of Europe. Haplogroups J and E (11.7 and 4.2%, respectively) mark the migration patterns of the Middle-Eastern agriculturists during the Neolithic. The presence of the N3 lineage (9.6%) is likely explained by a contribution of the assimilated Finno-Ugric tribes. The data on the composition and frequencies of Y-chromosome haplogroups in the sample studied substantially supplement the existing picture of the male lineage distribution in the Eastern Slav population.
The frequencies of three alleles, CCR5delta32 , CCR2-64I , and SDF1-3′A , known to decrease the risk of AIDS onset and the rate of the disease progression in HIV-infected individuals were determined in three native population samples from Russia, Ukraine, and Belarus. The frequencies of the alleles were 0.15, 0.12, 0.21; 0.12, 0.07, 0.20; and 0.12, 0.08, 0.26 for Russians, Ukrainians, and Belarussians, respectively. The proportion of the individuals without any of three protective alleles among Russians, Ukrainians, and Belarussians constituted 49, 65, and 61%, respectively. The genotype frequencies for the three loci studied were in Hardy–Weinberg equilibrium. Based on the three-locus genotype frequencies, the relative hazards of AIDS onset in HIV-infected individuals in each population were calculated as ranging from 0.79 to 0.88. In the samples of Eastern Slavs analyzed the estimated frequencies of the AIDS-protective alleles tested, as well as the frequencies of the corresponding genotypes and the relative hazards of AIDS onset were within the range of these parameters for the other European populations. The data on the allele frequencies and the relative hazard values in Russians, Ukrainians, and Belarussians can be used as the predictors of AIDS onset and progression rate in HIV-1-infected individuals from the populations studied.
Allele and genotype frequencies of the VNTR polymorphism in the third exon of human DRD4 gene were determined in 544 individuals living in Russia (Russians, Bashkirs, Tatars, and Mordovians) and in the neighboring countries (Kazakhs and Ukrainians). The data obtained were compared with the allele frequency distribution patterns reported for the populations of Eurasia. Similarly to other Eurasian populations, in our population samples R4 allele was prevalent (64 to 87%). The frequency of this allele in the populations of Western Europe constitute 61 to 71%, while in the populations of Asia it varies from 74 to 96%. In this respect, the populations studied occupied the intermediate position. In the samples examined the R7 allele frequency decreased from 7% in Ukrainians to 1% in Bashkirs, while in Kazakhs and Mordovians the allele was absent. This finding was consistent with the R7 allele distribution pattern in the populations of Eurasia, characterized by higher frequency in the West and lower frequency or absence of the allele in the East. In the group of 22 Eurasian populations, the R7 allele frequency negatively correlated with the frequency of the R4 allele ( r = -0.86 at P < 0.001). Unlike the R4 and R7 alleles, the frequency of which changed in the eastward direction, the R2 allele frequency distribution displayed slightly expressed latitudinal increase southwards. The DRD4 genotype distribution deviated from the equilibrium in most of the samples examined. In some samples, statistically significant increase of the R2/R2 homozygotes frequency was demonstrated. One of the possible explanations of this phenomenon is assortative mating with respect to phenotypic (behavioral) allele manifestation. The data obtained can serve as the basis for the investigation of the possible role of the DRD4 alleles as the risk factors for the development of alcoholism and other types of addictions.