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The comparative analysis of the associations between G20210A polymorphism of F2 gene, G1691A polymorphism of F5 gene, -5T/C polymorphism of gene GP1BA, I/D polymorphism of gene ACE and the risk of development of the stroke in two ethnical samplings--Russian and Ukrainian populations--was conducted. It was shown that the patients of the Russian population with genotype DD have a higher level of the risk of ischemic stroke development (OR = 1.4, 95% CI [1.05; 1.78], p = 0.02), whereas genotypes I/I and I/D are associated with the lower level of risk of ischemic stroke (OR = 0.7, 95% CI [0.56; 0.95], p = 0.02). In the Ukrainian ethnical sampling, differences in distribution of genotypes and alleles frequencies between patients with stroke and healthy persons upon given polymorphic locus are not significant, and I/D polymorphism of gene ACE is not associated with the risk of development of the stroke (OR = 0.8, 95% CI [0.48; 1.32], p = 0.45). The G20210A polymorphism of gene F2, G1691A polymorphism of gene F5, -5T/C polymorphism of gene GP1BA are not associated with the risk of stroke in two ethnical samplings.

Parkinson's disease (PD) is a multifactorial neurodegenerative disease whose pathogenesis involves a number of genes and environmental factors. The FGF20 gene encoding the fibroblast growth factor and paying an important role neuron proliferation and survival is one of candidate genes of PD. There is evidence that this gene is also involved in the control of alpha-synuclein (SNCA) gene expression. The rs12720208 single-nucleotide polymorphism (SNP) in the FGF20 gene has been found to be associated with PD; it has been located to the 3'-UTR binding site for microRNA-433, which is involved in the control of FGF20 expression. Therefore, the frequency distribution of rs12720208 genotypes in the FGF20 gene has been analyzed in a sample of patients with sporadic PD and a control sample of the Russian population. The results have not shown any effect of rs12720208 in the FGF20 gene on the risk of PD in patients residing in Russia (OR = 0.95, the 95% confidence interval (CI) is 0.55-1.63, p = 0.9).

Twenty-one SNPs located in the cluster of genes FMO1-FMO2-FMO3-FMO4 and adjacent areas were analyzed in the patients with ischaemic cardioembolic stroke and in the control group. Significant differences between these samples were found in the distribution of genotype and allele differences in two polymorphic loci, rs10912745 and rs4916375. It was shown that these polymorphic loci are associated with the risk of ischaemic cardioembolic stroke development.

The analysis of alleles and genotypes frequencies of 14 SNP in genes of rennin-angiotensin system (REN, AGT, AGTR1, AGTR2, BKR2, ADRB2) and hemostasis system (FGB, F2, F5, F7, ITGB3, SERPINE1, MTHFR), as well as ACE insertion-deletion polymorphism in patients with stroke comparing to healthy controls matched by age, sex and ethnicity has been carried out. The genotyping procedure included the amplification of selected gene sequences following by hybridization of fluorescently labeled fragments with SNP-specific DNA probes. The analysis of allele frequencies of each gene separately revealed no statistically significant differences between groups of patients with stroke and healthy donors. Also the complex study has been performed to estimate the contribution of rennin-angiotensin system and hemostasis system genes to the genetic susceptibility to ischemic stroke among Russians from Central Russia using method MDR (Multifactor Dimensionality Reduction). The combination with increased risk for development of ischemic stroke was presented by complex genotype FGB G/- x ACE I/- x MTHFR C/- x SERPINE1 5G/5G (p = 0.03, OR = 2.4, 95% CI 1.1-5.3), which frequency was statistically significant higher in patients with stroke compared to healthy control.

Allele and genotype frequencies of 10 single nucleotide polymorphisms in F12, PON1, PON2, NOS2, PDE4D, HIF1a,GPIba, CYP11B2 genes were studied in a group of Russian patients with ischemic stroke (IS) from central regions of the Russian Federation and healthy donors matched for sex, age and ethnicity. The genotyping procedure included the amplification of selected DNA sequences with the following hybridization of fluorescently-labeled regions with allele-specific DNA-probes immobilized on a biochip. An analysis of allele and genotype frequencies for each gene in IS patients and controls did not reveal any significant differences. The pair-wise comparison of genes demonstrated that the frequency of the combination PON1A/-x PON2 GG was higher in the group of patients (p=0.044, OR=3.4 95% CI 1.06 − 10.4) compared to the controls and, thus, was associated with the higher risk for stroke.

The analysis of association between DNA markers and total stroke risk was performed in 950 Slavonic patients. Patients with cardioembolic stroke were selected for a genome-wide association study. The HUMANCYTOSNP12 v.2 microchip was used to analyze all DNA samples on a panel of 301 000 single nucleotide polymorphisms. SNP rs1842993 on chromosome 7 was found to be associated with cardioembolic stroke risk.

Polymorphisms c.202G > A of prothrombin F2 gene, c.1691G > A of coagulation factor V F5 gene, c.675delinsG of plasminogen activator1 gene, and (-5)T > C Kozak gene of thrombocytic receptor were studied in the Russian and Moldavian ethnic groups. We have found no association between these polymorphisms and the risk of ischemic stroke development in both ethnic groups. No association was revealed between the risk of stroke development and various combinations of the single nucleotide polymorphisms examined in the sample of ischemic stroke patients from Russia.

A study of the immunomodulating effect of selank showed that the total peptide and its fragment significantly change the expression of the genes for chemokines, cytokines, and their receptors in mouse spleen 6 and 24 h after administration of a single dose. Changes in the mRNA level of the majority of the genes under study were similarly observed after the administration of Gly-Pro, which was earlier identified as a selank pharmacophor, a minimum fragment with anitiviral activity. Pharmacological preparations based on endogenous regulatory peptides are studied intensely because they are the most promising class of drugs and have almost no side effects. The class includes selank, which is a synthetic analog of taftsin. Selank exerts anxiolytic and nootropic effects and, on the other hand, has pronounced antiviral properties.

Parkinson's disease (PD) is the second most common progressive neurodegenerative disorder characterized by the degeneration of dopaminergic neurons. Detecting changes in gene expression in untreated de novo patients with PD is important for understanding disease pathogenesis and for identifying biomarkers for preclinical stage of PD. In this study we investigate expression of gene of Glycogen synthase kinase-3 beta (GSK3B) in the peripheral blood of different groups of patients with neurological diseases using reverse transcription reaction and real-time polymerase chain reaction (PCR). Our results suggest that the expression levels of GSK3B can't serve as a biomarker for early stages of PD.

A protein capable of activating 5-lipoxygenase (ALOX5AP) is considered a presumable risk factor of acute stroke development. Polymorphic variants of the ALOX5AP gene were examined. Two ALOX5AP gene polymorphisms (SG13S114 (rs10507391) and SG13S32 (rs9551963)), which previously had shown association with the risk of ischemic stroke in other populations, were studied. These single nucleotide polymorphisms were analyzed using a sample of acute stroke patients (N = 1320) and a control sample (N = 467). No statistically significant associations were found between acute stroke and the ALOX5AP gene polymorphisms examined.

An abnormal hyperechogenecity of substantia nigra is thought to be the most characteristic sonographic feature in Parkinson's disease (PD). However specificity and sensitivity of the ultrasound method should be refined. Using transcranial sonography, authors have examined 168 patients with different clinical signs of parkinsonism, including 99 patients with idiopathic PD, and 56 patients without extrapyramidal disorders. Hyperechogenecity of substantia nigra was found in 93% of patients and in 14% of controls. It has been shown that this biomarker can successfully discriminate PD from a number of similar disorders (essential tremor, atypical parkinsonian syndromes). Sonographic features of late, early and genetically determined parkinsonism specifying some pathogenetic aspects of these pathologies are described. Taking into account the data obtained, transcranial sonography can be considered as a highly informative method in the differential and early diagnosis of PD.

The risk of the ischemic stroke is mediated by both environmental and genetic factors. Recent studies of DeCode group identified the risk of polymorphisms for ischemic stroke in the phosphodiesterase 4D gene (PDE4D). The goal of this study was to explore the role of two variants of the gene encoding PDE4D [SNP41 (rs152312) and SNP87 (rs2910829)] in the Moldavian patients with ischemic stroke and in control. No significant association with ischemic stroke was observed with SNP41 and 87.

We studied SNP41 (rs152312) and SNP87 (rs2910829) of the PDE4D gene in 577 stroke patients and 270 healthy controls. The significant differences in the distribution of genotype and allele frequencies of the SNP41 between patients and controls were revealed. Genotypes AA and AG were associated with the higher risk of stroke in the Moscow population (OR 1,6). No association between SNP87 and stroke was found.

The Parkinson disease (PD) is the second most common progressive neurodegenerative disorder that arises due to degeneration of dopaminergic neurons. The causes of this disease are still unknown, but a number of genes involved in pathogenesis of familial and sporadic forms of PD has been identified. According to recent data of genome wide association studies (GWAS), single nucleotide polymorphisms (SNPs) in these genes (including MAPT locus) may play an important role in the development of PD. Therefore, we analyzed distribution of genotype frequencies of SNP rs415430 in the WNT3 gene in the Russian patients with sporadic PD and in the Russian population controls (OR = 0.84, Confidence Interval (95% CI) 0.58-1.23, p = 0.39). It was concluded that SNP rs415430 in the WNT3 gene was not associated with the risk of development of PD.

Two PDE4D gene polymorphisms [SNP41 (rs152312 and SNP87 (rs 2910829)] were studied in patients with acute stroke (n = 577) and in control sample (n = 270). Significant differences in the genotype and allele frequency distribution were found between these samples for polymorphism SNP41. We showed that the AA and AG genotypes of SNP41 polymorphism were associated with higher risk of acute stroke development in the Moscow population (OR = 1.6). No association of SNP87 polymorphism with the disease was observed.

Cerebrovascular diseases including stroke are an important problem of public health. Stroke development depends on external factors and individual genetic specificity of patient. Excessive NO production by inducible NO-synthase (iNOS) damages brain tissue at various stages of the disease. The goal of this work was to study the role of 4 polymorphic variants of gene of inducible NO-synthase iNOS (-2447C/G, -1659C/T, -0,7(OTTA)n I/D, S608L (150C/T)) in brain infarction in patients with acute ischemic stroke. A statistically significant correlation between S608L (150C/T) polymorphism and infarction dynamics was observed during days 1-3 and 7-21 after infarction. These parameters correlated with neurological status estimated using the Orgogozo scale during days 1-7 of the disease development. It was demonstrated that genotype N150N was associated with ischemic focus propagation regardless of its volume and neurological status by Orgogozo scale in patients with acute stroke. It was also observed that genotype N150N had effect on ischemic damage during days 1-3 in case of low initial volume.

Fifty-two patients that had ParkinsonTs disease with autosomal dominant type of inheritance were analyzed for the presence of duplications and triplications in exons 4--6 of alpha-synuclein gene using real-time PCR with Taq-Man probes. No mutations involving the examined exons dosage were revealed in alpha-synuclein gene. Thus, mutations modifying copy number of alpha-synuclein gene do not significantly affect the pathogenesis of the autosomal dominant form of ParkinsonTs disease in patients from Russia.

Association of 13 single nucleotide polymorphisms (SNPs) of insulinase (IDE) gene with type 2 diabetes mellitus (T2D) in the Moscow population has been examined. Three polymorphic markers (rs7078413, rs7899603, and rs551266) associated with the risk of T2D development have been revealed. Allele and genotype frequency distribution for these three markers differed significantly only in the sample of females between T2D patients and control individuals, while only in case of rs7078413 SNP genotype frequencies varied significantly in the total population.

The role of genetic predisposition to the formation of most multifactorial diseases, including stroke, was demonstrated in a number of investigations. To determine the individual genetic risk of a polygenic disease, the candidate gene approach is used most often. It is based on the analysis of polymorphic variants of certain genes taking into consideration the function of their protein product. But this approach is limited by the analysis of defined genes and does not detect new groups of genes, which involved in the pathogenesis of cerebral stroke. Genome-wide association study is a wide-range analysis of whole-genome polymorphisms, which allows to compare the distribution of allele frequencies in stroke patients and healthy individuals. The use of this method for the determination of individual genetic risk of acute stroke allows to perform molecular-genetic screening of most significant markers of stroke predisposition; to determine patients with the highest risk of stroke and to perform the mass health examination with preventive therapy prescription. The genome-wide association study to determine the individual genetic risk of stroke, taking into account ethnic origin, is performed in the Russian Federation since 2008 on the basis of the Neurological clinic of the Russian State Medical University in collaboration with the Institute of Molecular Genetics, Russian Academy of Sciences.

Parkinson's disease is a complex disease characterized by a progressive degeneration of nigrostriatal dopaminergic neurons. Development of this condition is defined by interaction between the genetic constitution of an organism and environmental factors. The analysis of the genes associated with development of monogenic forms of disease, has allowed pointing out proteasome degradation, the differentiation of dopaminergic neurons, the mitochondrial dysfunction and oxidative damage. In this review a variety of data which indicate on a key role of the mitochondrial dysfunction and oxidative stress in Parkinson's disease pathogenesis will be more detail considered.

Semax is a synthetic peptide, which consists of the N-terminal adrenocorticotropic hormone fragment (4-7) (ACTH4-7) and C-terminal Pro-Gly-Pro peptide. Semax promotes neuron survival in hypoxia, increases selective attention and memory storage. It was shown that this synthetic peptide exerted a number of gene expressions, especially brain derived neurotrophic factor gene (Bdnf) and nerve growth factor gene (Ngf). Temporary dynamics of Bdnf and Ngf ex- pression in rat hippocampus and frontal cortex under Semax action (50 mg/kg, single intranasal administration) was studied in this work. It was shown that the studied gene expression levels changed significantly both in the hippocampus and the frontal cortex tissues 20 minutes after the peptide preparation application. The expression levels decreased in the hippocampus and increased in the frontal cortex. Forty minutes after Semax administration both gene expression levels returned to the level typical of control tissues. After that they increased significantly by 90 minutes after experiment start. Bdnf and Ngf expression levels decreased up to the control levels by 8 hours after medicine applying maximum gene expression levels were attained. Thus, Semax administration results in rapid, long-term, and specific activation of Bdnf and Ngf expression changes in different rat brain departments.

A recently described form of Parkinson's disease - PARK8 - is caused by mutations in the novel LRRK2 gene on chromosome 12q12. The most common mutation in this gene is the substitution G2019S and we studied it for the first time in a large group of Russian Slavonic patients (311 patients) with Parkinson's disease including 295 sporadic and 16 familial cases. The mutation LRRK2-G2019S was identified in 1% of patients examined (3 cases) and was not found in a group of population control. The clinical picture of all patients with the LRRK2-G2019S mutation was typical for levodopa-responsive parkinsonism and age of disease onset varied widely (from 39 to 71 years). Two different PARK8-linked haplotypes were found in carriers of the mutation that suggested the independent origin of the G2019S mutation on different chromosomes. The identification of mutations in the LRRK2 gene in patients with "ordinary" sporadic Parkinson's disease has serious implications for medical genetic counseling and prognosis in respective families.

The current views on the role of genetic factors in the pathogenesis of Parkinson's disease are considered. The review is focused on monogenic forms of the disease, for which 11 loci are mapped and seven genes whose mutations cause the disease are identified. In addition, a number of candidate genes for sporadic Parkinson's disease are described. The further development of studying genetic bases of Parkinson's disease will follow two main directions: in-depth analysis of genes related to the monogenic form of the disease and more large-scale associative investigation of candidate genes for the sporadic form of Parkinson's disease.

The IVS9-675C > A polymorphism of the HIF-1alpha gene was analyzed in patients with acute ischemic stroke and in a control group. The genotype and allele frequencies proved to significantly differ between the two groups. Allele C and genotypes containing this allele were associated with a higher risk of stroke in the Moscow population.

Motor neuron disease (MND) is caused by selective degeneration of motor neurons of the cerebral cortex, brain stem and spinal cord. Many genetic systems are thought to be involved in pathogenesis of this complex disease. A significant etiological factor of MND may be oxygen free radicals, which damage neuronal cells when they are present in high concentrations. Detoxication processes resulting in the formation of free radicals, which subsequently transformed into nontoxic products, are also critical for the disease development. The major participants of these processes are cytochromes P-450 (CYP2E1, CYP2D6), glutathione-S-transferases (GSTM1, GSTT1, GSTP1) and N-acetyltransferases (NAT2). To investigate a role of genes of detoxication system in development of MND, we study polymorphisms in these genes in 72 patients with MND from Moscow and controls from Russia. Significant statistical differences have been found in frequency of the alleles CYP2E1*1D, CYP2D6*4 and GSTM1(0/0) and genotypes homozygous for GSTM1 (0) between the study and control groups. The analysis of GSTT1, GSTP1 and NAT1 gene polymorphisms has revealed no between-group differences in distribution of different alleles and genotypes. The GSTP1*A/ GSTP1*A genotype was associated with a classical upper and lower motor neuron involvement and the GSTP1*A allele with predominant lower and upper motor neuron involvement.

Polymorphisms of the genes of the glutamatergic system EAAT2, GRIA1, and GRIA2 have been analyzed in patients with sporadic motor neuron disease (MND) from Russia. The disease is not associated with polymorphic alleles of the genes studied, which indicates that EAAT2, GRIA1, and GRIA2 play an insignificant role in the pathogenesis of sporadic MND.

Ile105Val polymorphism in exon 5 of glutathione S-transferase (GSTP1) gene was examined in a group of patients with motor neuron disease (MND) and control sample. No statistically significant differences in the allele and genotype frequency distributions between the samples examined were demonstrated. We conclude that Ile105Val polymorphism is not associated with the risk of the disease development in the patients from Russia with sporadic form of MND.

The review summarizes the results of a decade of molecular genetic studies of several high-incidence hereditary neurodegenerative diseases, including primary parkinsonism, various forms of hereditary dystonia and ataxia, polyglutamine disorders, hepatolenticular degeneration, essential tremor, etc. Various relevant mutations were studied. The character and frequencies of particular mutations and the corresponding genetic disorders were established for the Russian population. Particular genotypes were associated with various clinical variants of the diseases. Genetic loci were identified for several unique hereditary diseases of the nervous system (X-linked cerebellar hypoplasia, an atypical form of autosomal recessive muscular dystrophy, etc.). Nosological positions of the relevant clinical forms were clarified on the basis of the molecular genetic data. Protocols were developed for direct or indirect DNA diagnostics of the diseases under study to improve medical genetic counseling and prevention of new disease cases in affected families.

Clinical and genetic analysis of juvenile parkinsonism was performed in 26 sibs from 20 families. Heterogeneity of the disorder was observed. Mutations in the parkin gene (locus PARK2, chromosome 6q25.2-27), with the prevalence of deletions over point mutations, have been identified in 41%. The comparative clinical analyses of patients examined confirmed the phenotypical polymorphism of "parkinopathy". We also showed the absence of asymmetric manifestation--an important and underestimated so far sign of the disease. The results of the study may be considered as a valuable clue to the clinical diagnosis of parkin-related juvenile parkinsonism in Russian population and implemented for mutation screening and medico-genetic counseling of affected families.

A method for analysis of deletions and duplications of individual exons and groups of exons in the parkin gene (PARK2) in both homozygous and heterozygous states has been developed. The method is based on semiquantitative polymerase chain reaction (PCR). The method has been used for analysis of the frequency of deletions in gene PARK2 in patients with idiopathic Parkinson's disease from Bashkortostan. Two unrelated patients have been found to carry a deletion of the 12th (last) exon of gene PARK2. Possibly, this deletion has caused the disease in the given patients.

A significant association between Bam HI RFLP p53 gene polymorphism and brain infarction volume in patients with atherothrombotic ischemic stroke (AIS) from Moscow population was found. Biallelic Bam HI polymorphism in exon 5 of p53 gene was studied in 96 AIS patients, 100 their healthy siblings, 41 patients with chronic ischemic disease and 42 their healthy siblings. Magnetic resonance tomography with morphometric program "Osiris" (the Hospital of the University, Geneva) for infarction volume measuring was used on day 1 and 7 after stroke onset. The patients with (-/-) p53 Bam HI genotype had the smaller brain infarction sizes (< 40 cm3), comparing to those with (-/+) (chi 2 = 19.7; p < 0.001) and (+/+) (chi 2 = 12.3; p < 0.001) genotypes. According to Bayes statistics, development of smaller infarction size in AIS may be predicted with over than 65% probability in the patients with (-/-) p53 Bam HI genotype. A significant association between p53 Bam HI polymorphism and infarction volume in patients with carotid atherothrombotic stroke confirms an important role of apoptosis in ischemic brain lesions formation that demands temporary antiapoptotic influence on patients with stroke.

Possible correlation of M/T polymorphism of angiotensinogen gene with risk of ischemic stroke and basic risk factors of cerebral pathology (levels of arterial pressure and blood cholesterol; presence of diabetes mellitus, coronary heart disease, or myocardial infarction in anamnesis; and stenosis of major cerebral arteries) was studied. It was shown that M/T polymorphic variants of angiotensinogen gene were factors determining neither clinical variant of cerebral ischemia development (acute ischemic stroke or chronic brain ischemia) nor formation of main risk factors of stroke.

Polymorphic variants of genes for angiotensin-converting enzyme (ACE) and angiotensinogen (ATG) were studied in 110 patients with different types of brain ischemic disease--carotid atherothrombotic ischemic stroke (one of the pathogenic brain infarction variants) as well as in 119 their siblings with the main risk factors of cerebrovascular pathology development being taken into account. No association has been found between ACE and ATG genes polymorphisms and carotid atherothrombotic ischemic stroke. However, the presence of a homozigous DD ACE genotype was shown to be an independent risk factor for development of hemodynamically relevant stenosis of the major brain arteries. The absence of differences in genetic variants distribution in patients with acute ischemic stroke, comparing to those with prolonged chronic brain ischemic disease (without infarction formation) and the highest frequency of this polymorphism in "longevity" group (without lifetime stroke) imply a relatively independent character of the atherothrombogenic process, which may probably underlie a further development of pathological process.

Fifty-one blood samples of Russian patients with sporadic motor neuron disease were examined for mutations in Cu/Zn superoxide dismutase (SOD-1) gene. One female patient with amyotrophic lateral sclerosis (ALS) was heterozygous for G12R mutation. This patient suffered from ALS with cervical cord onset, pyramidal variant and fast progression. Mutation was also detected in her healthy son. Earlier, such mutation was described in 5 Italian patients with slow progressive ALS. Also, D90A SOD-1 gene associated haplotypes of the female ALS patients previously examined by the authors have been analyzed. A homozygous female patient with ALS was characterized by typical lumbar onset and extremely slow progression, as well as a female patient with heterozygous mutation and moderate progression carried so-called "Scandinavian" haplotype. To our knowledge, it is the first report on the finding of the haplotype considered as a "protective" one in the subjects heterozygous for D90A mutation with clinical symptoms of ALS. Mechanisms of "protective" influence of this haplotype on ALS course are not yet elucidated. Our finding suggests that the presence of "Scandinavian" haplotype does not completely protect from the disease development in patients exposed to other more pathogenic causative factors. This assumption is in line with modern conceptions on motor neuron disease as a complicated multifactor disorder.

We analyzed distribution of heavy neurofilament (NF-H) gene S/L-polymorphic variants in 51 patients with idiopathic motor neuron disease (MND) vs control group and in relation to superoxide dismutases (SODs) activity and thiobarbituric acid reactive substances (TBARS) level in cerebrospinal fluid (CSF), erythrocytes and blood serum. We found that individuals with homozygosity for NF-H gene short allele (S/S-genotype carriers) in MND group predominate significantly over those in control one (p < 0.001). We revealed significant increase of oxidative markers in CSF and blood serum in MDN patients vs controls (p < 0.05), but not in patients with spondylogenic myelopathy, conforming non-specific role of oxidative stress in MND pathogenesis. There were no differences between TBARS level in CSF and serum in relation to the rate of MND progression, suggesting that oxidative stress does not influence the MND course. We showed normal SOD-1 activity in erythrocytes and CSF of MND patients that argued for the absence of these antioxidant enzymes deficiency in MND without SOD-1 gene mutations. We found significant association between homozygosity for short allele (S) and increased TBARS level in CSF (p < 0.02). These findings specify the role of NF-H with lower molecular weight in MND pathogenesis and make expedient antioxidants administration to MND patients homozygous for S-allele of NF-H gene.

A simple and rapid method for detecting the 1069Gln mutation in gene ATP7B based on a PCR specific for this allele has been developed. The 1069Gln mutation is the main cause of Wilson disease (WD) in Russia and accounts for approximately 40% of all mutant alleles of gene ATP7B. Therefore, the method proposed makes the postnatal and prenatal diagnosis of Wilson disease in Russia considerably more rapid and less expensive.

Polymorphism of highly polymorphic triplet repeats CTG of the 3'-untranslated region of the myotonin protein kinase gene and CAG of the genes associated with dentatorobral-pallidoluysian atrophy (DRPLA, or Hew River syndrome) and spinocerebellar ataxia type 1 (SCA1) was analyzed in several ethnic populations of Russia. A difference in allele spectra of the three genes was demonstrated for populations differing in ethnic origin.

Comparison of the frequency distributions of alleles, genotypes, and genotype combinations of genes GSTM1 and GSTT1 did not show statistically significant differences between patients with motor neuron disease (MND) and a random sample from the Moscow population. Apparently, these genes are not involved in MND pathogenesis in these patients.

Frequencies of the wild-type and null genotypes of the GSTM1 and GSTT1 genes were established in healthy donors from several Russian populations (ethnic Russians from the towns of Oshevensk and Kholmogory, Arkhangel'sk oblast; ethnic Khants; ethnic Kalmyks; and ethnic Buryats) in order to identify the ethnic group with the maximal frequency of the null genotype. The highest frequency of individuals with the null genotype of both genes was observed in the Kalmyk and Buryat populations. The results may be used to study the effect of climatic and ecological conditions on multifactorial disease incidence in populations.

A DNA analysis of 72 patients from Bashkortostan clinically diagnosed with myotonic dystrophy and 54 their family members was conducted. CTG-repeat expansion in the myotonin proteinkinase gene was found in 67 (92%) patients and 12 their relatives without clinical symptoms of the disease at the moment of examination. A correlation between the most distinct clinical symptoms and CTG-repeat number has been studied. A CTG-repeat expansion in generations was compared to that in sib pairs with myotonic dystrophy. In 17.6% of the cases, CTG-repeat number decreased in the following generations and in 11.7% it did not change, the percentages being higher than those described elsewhere. In general, anticipation phenomenon was confirmed for CTG-repeat in myotonin proteinkinase gene.

Insertion-deletion polymorphism of the gene for the angiotensin-converting enzyme has been investigated in random samples from various age groups in the Moscow population. A statistically significant reduction in the insertion allele frequency has been found in senior age groups.

Allelic polymorphism of five microsatellite loci of the human Y chromosome (DYS19, DYS390, DYS391, DYS392, and DYS393) was analyzed in samples of male populations from Ukraine, Russia, and Belarus (152 subjects in total). The allelic diversity indices (Dg) were determined for all loci; they varied from 0.23 to 0.72. The mean values of this parameter in the Ukrainian, Russian, and Belarussian populations were 0.45, 0.47, and 0.52, respectively. A total of 53 different haplotypes were found in 152 subjects from three populations. The most frequent haplotype was found in 14.5% of the subjects, whereas 35 haplotypes (23%) were each found in only one person. The haplotypic diversity index (Dhp) was 0.94. The genetic distances between the populations studied and some populations of Western and Central Europe were estimated. These data were used to construct a phylogram (tree) of genetic similarity between the populations, which demonstrated that the three Eastern Slavic populations are genetically close to one another and remote from Western European populations.

Polymorphisms of the genes for angiotensin-converting enzyme (ACE) and angiotensinogen, the proteins of the renin-angiotensin system (RAS), were tested for association with the polymetabolic syndrome (PMS) and non-insulin-dependent diabetes mellitus (NIDDM) in the Moscow population. The insertional (I) allele and genotype II of the ACE gene proved to be associated with PMS. A significant difference in allele and genotype frequency distributions of the (CA)n microsatellite of the 3'-untranslated exon of the angiotensinogen gene was revealed between randomly sampled individuals and patients with PMS and IDDM from the Moscow population.

Allele frequency distributions of the insertion/deletion (I/D) polymorphism of the angiotensin-converting enzyme (ACE) gene and the M235T polymorphism of the angiotensinogen gene was studied in a random sample of the indigenous population of the Sakha Republic. The allelic variants of these genes did not showed an association with blood pressure in Yakuts.