[Features of the course of anterior uveitis associated with HLA-B27 antigen]. / Osobennosti techeniia perednikh uveitov, assotsiirovannykh c HLA-B27-antigenom.

PURPOSE: To perform comparative analysis of the frequency of various complications of anterior uveitis associated with HLA-B27 antigen in patients with and without spondyloarthritis. MATERIAL AND METHODS: Retrospective analysis included 189 patients with anterior uveitis (AU) associated with histocompatibility antigen (HLA-B27). The Follow-up period lasted 10 years. RESULTS: 189 patients with AU associated with antigen HLA-B27 were divided into two groups. The first group included 108 patients with various diseases of the spondyloarthritis (SpA) group; the second study group consisted of 81 patient with no signs of SpA. Number of patients with complications was 1.5 times higher in the first group. Complicated cataract, glaucoma, synechiae, myodesopsia occurred significantly more frequently in patients of the first group compared to AU patients of the second group, where idiopathic AU was more prevalent. Cystoid macular edema, corneal degeneration, optic nerve atrophy were observed more often in patients with SpA, but differences between the groups were statistically insignificant. Combination of complications also occurred significantly more often in SpA patients. Comparison of the frequency of AU attacks showed that the amount of uveitis attacks per 100 patient-years was higher in patients with SpA. Mean number of AU attacks per year was also higher in the first study group, but differences between the groups were statistically insignificant. CONCLUSION: Retrospective analysis of 189 patients with AU associated with HLA-B27 antigen revealed significantly higher frequency of complications, together with more frequent acute episodes in patients with SpA in comparison with patients without it confirming the notion that a systemic inflammatory disease can influence the severity of the course of AU.

Association of polymorphisms of HLA-DRB1 and TNF-308 G/A with radiographic joint damage in patients with early rheumatoid arthritis with high inflammatory activity, treated according to the principle of "Treat to target" (REMARKA study).

AIM: To clarify the association between HLA-DRB1 and TNFα (-308G>A) genes polymorphism and joint destruction/further progression during 12 months of the follow-up period (FUP) in patients with early (<6 months), active, predominantly antibodies to cyclic citrullinated peptide (ACCP) and rheumatoid factor (RF)-positive rheumatoid arthritis (RA) treated according to "Treat to target" strategy. MATERIALS AND METHODS: The study included 85 patients with early RA and duration of symptoms <6 months. All patients were initially assigned to subcutaneous methotrexate (MTX) with rapid dose escalation to 20-25 mg/week. Combination MTX + biological therapy, mainly adalimumab, was used when MTX was ineffective. Joint destruction was assessed by Sharp-Van der Heijde modification scoring method at baseline and after 12 months FUP. Real time polymerase chain reaction (PCR-RT) was used for TNFα gene polymorphism (-308G>A) genotyping. Low resolution PCR-RT with subsequent sequence-based typing of *04 were performed to study HLA-DRB1 gene polymorphism. The HLA-DRB1*01, *04:01, *04:04, *04:05, *04:08, *10 alleles were categorized as SE+ (Shared Epitope) alleles. RESULTS: As for TNFα gene polymorphism, it was demonstrated that the number of narrowings and total Sharp score values were almost twice as high at baseline in GG genotype carriers as compared to GA genotype carriers (р<0,005, and р<0,004 respectively). Similar association was found after 12mo FUP. The progression of joint destruction, assessed as the change (∆) in the number of erosions, joint space narrowings and the total score, was statistically significantly associated with HLA-DRB1*(SE) genotypes: the carriers of SE (SE+/SE+) double-dose had more advanced progression as compared to (SE+/SE-)/(SE-/SE-) carriers (р<0,028, р<0,019, р<0,035 respectively). CONCLUSION: Our data suggest that HLA-DRB1 (SE+) gene and TNFα (-308G>A) polymorphisms are associated with the progression of radiographic joint destruction in early, active RA patients managed according to "Treat to target" stratagy.

[Uveitis-associated HLA class 1 histocompatibility antigens]. / Uveity i ikh assotsiatsiia s antigenami gistosovmestimosti klassa 1.

AIM: to evaluate the diagnostic and prognostic significance of HLA class 1 histocompatibility antigens in the development of anterior uveitis. MATERIAL AND METHODS: A total of 137 patients with anterior uveitis followed up at the Research Institute of Eye Diseases in 2009-2016 were tested for HLA antigens (A and B loci). The average patient's age was 29±12.4 years. All patients underwent a thorough medical interview with clinical and laboratory assessment. In case of suspected association with systemic disease, the patients were referred for consultation at the V.A. Nasonova Research Institute of Rheumatology. HLA typing was performed using a standard microlymphocytotoxicity test with specific anti-HLA sera (production of Gisans CC, Saint Petersburg). Statistical processing was performed with Statistica 6.0 software by applying methods of descriptive and nonparametric statistics (Mann-Whitney test). RESULTS: The results of HLA class 1 typing indicated a significant positive association between uveitis and the HLA-B27 antigen (p<0.00001). Moreover, there was a trend toward decreased frequencies of В7, B12, and B21 antigens (p=0.1), however, the changes were not statistically significant as compared to the control group. Other HLA class 1 antigens also did not differ significantly in frequency between uveitis patients and the controls. CONCLUSION: The study has confirmed an association between certain histocompatibility antigens and systemic diseases. However, a statistically reliable relationship has been established only for the HLA-B27 antigen.

[The influence of STAT4 rs7574865 (G/T) polymorphism on the risk of clinical and immunological phenotypes of systemic sclerosis in a Russian patient population: Results of a pilot study]. / Vliianie polimorfizma rs7574865 (G/T) gena STAT4 na risk razvitiia klinicheskikh i immunologicheskikh fenotipov sistemnoi sklerodermii v russkoi populiatsii bol'nykh: rezul'taty pilotnogo issledovaniia.

AIM: To examine the association of signal transducer and activator transcription 4 (STAT4) rs7574865 G/T polymorphism with a predisposition to systemic sclerosis (SSC) and associated clinical and autoimmune phenotypes in a Russian population. SUBJECTS AND METHODS: A total of 102 patients with SSC and 103 healthy individuals as controls were examined. STAT4 rs7574865 polymorphism was investigated by real-time polymerase chain reaction. RESULTS: The carriers of the T allele showed a statistically significant association with SSC, a diffuse form (DF), the presence of interstitial lung disease (ILD), cardiac injury (CI), and seropositivity for anti-topoisomerase I antibodies (ATA). CONCLUSION: The findings results confirm the important role of STAT4 gene in the predisposition to SSC and its phenotypes, such as DF, ILD, CI, and ATA in the Russian population.

[Uveitis in spondyloarthritis patients and its association with HLA-B27 histocompatibility antigen: prospective study]. / Prospektivnoe issledovanie uveitov pri spondiloartritakh i ikh assotsiatsii s antigenom gistosovmestimosti HLA-V27.

AIM: to perform a prospective study of clinical presentation and course of uveitis in spondyloarthritis (SpA) patients as well as its association with the HLA-B27 histocompatibility antigen. MATERIAL AND METHODS: The study included 219 patients with uveitis, all tested for HLA-B27 antigen and various infections (viral, bacterial, and parasitic) as well as examined for locomotive system involvement. RESULTS: The presence of the HLA-B27 antigen was determined in 142 (64.8%) out of 219 patients, of them 87 were diagnosed with an entity of the SpA group. The remaining 77 (35.2%) patients appeared to be HLA-B27-negative, but 13 were still diagnosed with an entity of the SpA group. There were 10 (4.6%) patients with 2 or more diseases from the SpA group («clinical decussation¼). When comparing the two groups of HLA-B27-positive and negative patients having both SpA and uveitis, no statistically significant difference was found as to the age of onset, site, frequency of attacks, and uni- or bilateral involvement (p>0.05). We also performed a comparison of HLA-B27-positive and negative patients with no account to their SpA status and revealed a higher complication rate in those that were «negative¼ (p<0.0001), which can be explained by the fact that HLA-B27-negative patients often have autoimmune or infectious uveitis of different origin notable for long attacks and short remissions. CONCLUSION: Assessing the site and course of uveitis as well as HLA-B27 testing of uveitis patients has proved important for etiological diagnosis. Diseases of the SpA group have been shown to be 6.7 times more common in HLA-B27-positive patients as compared to HLA-B27-negative ones. Clinical presentation of uveitis in the presence of SpA in both HLA-B27-positive and negative patients resembles that of idiopathic uveitis - an independent HLA-B27-associated syndrome (р>0.05). Cases of «decussation¼ between entities of the SpA group are usually more severe in terms of clinical presentation and course of uveitis and are associated with a worse prognosis. Complications of uveitis are more likely to be found in non-SpA HLA-B27-negative patients (р<0.0001).

[Immunogenetic aspects of early rheumatoid arthritis].

The study is aimed to investigate the distribution of alleles of HLA-DRB1 gene in patients with early rheumatoid arthritis and healthy individuals in Russian population, and evaluate their significance as molecular genetic markers of rheumatoid arthritis predisposition and protection. The association between alleles of HLA-DRB1 genes, antibodies to cyclic citrullinated peptides and IgM rheumatoid factor was also studied. Low and high resolution HLA-DRB1 genotyping were compared. In the cohort of patients with early rheumatoid arthritis, the alleles of HLA-DRB1 gene were found to be markers of rheumatoid arthritis protection/risk, especially in the homozygous state. They determined production of antibodies to cyclic citrullinated peptides but were not associated with rheumatoid factor IgM levels. These findings support different autoimmune mechanisms of rheumatoid arthritis pathogenesis.

[Behcet's disease and associations with HLA-B5 antigen (a review of literature and the authors' findings)].

AIM: To estimate the distribution of HLA Class I (A, B) antigens in patients with Behcet's disease (BD) and the association of HLA-B5 antigen with the clinical manifestations of the disease in different ethnic and population groups in relation to gender. SUBJECTS AND METHODS: The study covered 93 patients (68 males, 25 females) from the representatives of 24 ethnicities with the verified disease. HLA Class I antigens were typed by the microlymphocytotoxic technique, by applying an antileukocytic serum kit (GISANS, Saint Petersburg). RESULTS: In patients with BD, the prevalence of HLA-B5 antigen proved to be significantly higher than that in the controls (72.0 and 21%, respectively) and to be similar in patients of different ethnicities living in the Caucasus and Transcaucasus (80-83%) while the number of HLA-B5 antigen-positive patients with BD was thrice less in the Russian population than in other BD patients (p < 0.01). There was a significant correlation of HLA-B5 antigen with ocular lesion (retinal angiitis) predominantly in male patients with BD. CONCLUSION: The prevalence of HLA-B5 antigen was higher in patients with BD than in the population-based control. The diagnostic value of this antigen is not so great, for example, in the Russian population of patients with BD. The presence of HLA-B5 antigen in the phenotype of male patients with BD may be regarded as a prognostically poor marker of development of eye diseases.

[Clinical and immunological aspects of early-stage rheumatoid arthritis].

Rheumatoid arthritis (RA) is a chronic autoimmune disease that is characterized by a systemic inflammatory and destructive joint lesion that is manifested by the involvement of various organs and systems into the pathological process. Whether the variants of the course and outcomes of RA may be predicted early is the most important inadequately studied problem. HLA-DRB1* genotypes affect disease severity; however, different alleles encoding the identical amino acid sequence have a varying association with the disease and their combinations can differently increase the risk of RA. Total epitope (SE) is associated not only with the risk of RA as a whole, but also with the development of the severe course of the disease to a greater extent. A number of studies have demonstrated that if a patient has concurrently antibodies to cyclic citrullinated peptide (CCP) and rheumatoid factor, as well as HLA-DRB1 alleles, the likelihood of rapid X-ray progression is 10 times greater than that in a patient without these markers. The paper considers the course of early RA depending on the combined determination of immunological and immunogenetic markers (SE and CCP antibodies). Each of them makes a substantial contribution to the development of a destructive process in early RA, which necessitates the assessment of a combination of the factors.

Clinical effects of anxiolytic preparation tenoten in complex therapy of essential hypertension.

Addition of modern daily anxiolytic tenoten to complex therapy of patients with arterial hypertension improves the efficiency of treatment and reduces anxiety, which accelerates the development of hypotensive effect. Tenoten can be recommended for the treatment of anxiety symptoms in patients with arterial hypertension.

[Behcet's disease and joint affection].

AIM: To study joint pathology in patients with Behcet's disease (BD). MATERIAL AND METHODS: The trial enrolled 183 BD patients (128 males, 54females, mean age 32.0 +/- 9.8 years, age at BD onset 22.3 +/- 9.9 years, mean duration of the disease 9.5 +/- 8.9 years. RESULTS: Joint pathology occurred in 74.8% patients, in 10.9% patients the disease onset was associated with arthritis and arthralgia. 3 patients had aceptic necrosis of the head of the femur and knee joint, 3 patients--bone marrow infarction. Knee joints were affected more frequently than others (up to 40%) followed by ankle, elbow and radiocarpal and other joints. In BD duration about 10 years, none of the examinees had stage III of sacroiliitis, stage II was diagnosed only in 4 patients, stage I (suspicion)--in 9. Significant sacroillitis was not registered, bilateral sacroiliitis occurred only in 9 patients. HLA B5 was detected in 61% patients while HLA B27--only in 9.7%. CONCLUSION: The articular syndrome was seen in 3/4 of BD patients. Arthritis runs a recurrent course. Erosive arthritis, sacroiliitis and combination of the latter with HLA B27 are rare.

[State-of-the-art immune genetic and immune biological aspects of rheumatoid arthritis].

One of the actual problems of clinical rheumatology was and remains the necessity of the earliest diagnostics of rheumatoid arthritis (RA) with the aim of adequate therapy for prevention of development of destructive changes, function ability loss and complication leading to reduction in patient's life quality, invalidization and lethal outcome. The predictors of the course of disease in its early stages, knowledge of its development mechanisms, are the base for optimal therapeutic influence on specific targets with the existing drugs and for development new ones. State-of-the-art data in genetic and immunological RA markers, whose detection in RA early stages helps to make RA diagnosis and to predict the disease course are represented. Immunological markers-antibodies to cyclic citrullinized peptide (aCCP) and rheumatoid factor (RF) have high specificity and sensitivity to RA diagnostics. Some alleles of the HLA-DRB1 locus coding shared epitope (SE) play the role of immune genetic factor predisposing to RA development and giving additional information for RA diagnostics in case of negative values of aCCP and RF.

[Vascular symptoms of Behcet's disease].

AIM: To characterize vascular symptoms of Behcet's disease (BD) in patients treated for the last 10 years in the Institute of Rheumatology. MATERIAL AND METHODS: Vascular symptoms of BD were studied in 151 patients with BD (mean age 33.5 +/- 9.5 years, duration of the disease 14.0 +/- 10.1 years, 104 males and 47 females, 67.4% carried HLA B51(5) antigen). Duplex vascular scanning was made to detect venous thrombosis. RESULTS: Thrombotic complications were found in 37 of 151 (24.5%) patients with BD (30 males and 7 females, mean age 37.1 +/- 9.1 years, mean duration of the disease 7.3 +/- 9.7 years). Venous thromboses prevailed (36 patients). Four males (2.6%) had arterial lesions: aneurysms of the iliac arteries (n = 1), thrombosis of the iliac artery (n = 1), pulmonary infarction and thrombosis of the pulmonary arteries (n = 2). Combination of venous and arterial manifestations occurred in 3 patients. One patient had thrombosis of the venous sinus, occlusion of the retinal vessels was diagnosed in 7 patients. CONCLUSION: Incidence of vascular disorders was observed in 1/4 of the patients. This corresponds to those observed worldwide and concerns venous thrombosis and other thromboses. Among the examinees, vascular disorders were associated with a young age, earlier development of thrombotic complications in males than in females.

[A search for genes of predisposition to rheumatoid arthritis]. / Poisk genov predraspolozhennosti k revmatoidnomu artritu.

Rheumatoid arthritis belongs to the group of autoimmune multifactor diseases with an essential involvement of genetic components in its genesis. The HLA DRB1* polymorphism was studied in 68 RA patients and in their 75 healthy relatives. 135 blood donors, who were tested at the Institute for Immunology of the Ministry of Health, Russian Federation, Moscow, were in the control group. The carrier-state of the HLA DRB1* 04 gene contributes to a higher probability of RA onset by 8.5 times, while the presence, in genotype, of genes HLADRB1* 02, 05, 06 reduces the risk of RA by 2.1, 2.3 and 7.2 times, respectively. Allele *0401 is encountered reliably more often in RA patients versus healthy controls. Within a sample of patients with familial RA, 43.9% turned out to be the carriers with various combinations of two alleles of genes coding the conservative amine acids of sequences QKRAA or QRRAA, which were named "shared epitope" (SE), versus 5.1% among the controls. The presence of homozygous "SE genotypes" among the RA patients contributed to a higher risk of morbidity by 5.8 times, while the carrier state of haplotypes with "duel SE positivity" enhanced the risk of morbidity by 17.8 times mainly due to the 01/0401 halotype. The RA linkage with two intragenic DNA markers, i.e. with the polymorphous micro-satellite replication of gene TCRA (CA)n and with the point-type changeability (localized in the coding area of the second variable region of V2 TCRD gene), was analyzed. The maximal possible value of the lod-point for (CA)n, i.e. replication of TCRA gene, was equal to +1.30 in males under the condition of zero recombination frequency, and to 16% of frequency recombination in females. The maximal possible value of the lod-point for the point-type changeability of gene TCRD was equal to +0.70 in males under the conditions of zero frequency recombination and to 40% of frequency recombination in females. The maximal lod-point value amounting to +1.20 in males and females in an identical frequency recombination of 5% was found on the basis of a three-point analysis of the linkage between RA and two intragenic markers from gene clusters coding the alpha- and beta-chains of T-cellular receptors. Therefore, our familial data are indicative of the opportunity of localizing the gene predisposed to RA is at a distance of 5 cM, in the direction of the telomere, from the locus of the examined (CA)n, i.e. replication of gene TCRA.

[Articular lesions in Ixodes tick-borne borreliosis (Lyme disease)]. / Porazhenie sustavov pri iksodovykh kleshchevykh borreliozakh (laimskoi bolezni).

Articular lesions in 157 patients infected with ixodes tick-borne borreliosis (ITB) in a central Russia's region set on, on the average, in 4 months after tick attack; they were associated with systemic signs of an early disseminated infection and set on less seldom in a late period. The most often encountered systemic signs were as follows: secondary erythema (32% of patients), neurological syndrome (13%), cardio-vascular lesions (22%), ocular lesions (13%) and hepatic lesions (8%). The articular syndrome manifested itself through arthralgia (53 patients) and arthritis (104 patients), which set on quite often in the tick-attack area. There was a peculiarity typical of articular lesions, which made it possible to distinguish them from other rheumatic disease. A dynamic follow-up revealed different clinical variations of Lyme's arthritis and peculiarities of the genetic profile, i.e. a higher prevalence of HLA A2, HLA-B15 and HLA-DR4 as well as of haplo-types HLA A2-B15 and HLAB15-DR4. The articular lesions were associated with an intensive specific humoral immune response. The instrumental examination methods, i.e. ultrasonography of joints as well as scintigraphy of bones and joints, did not reveal any qualitative differences between arthralgia and arthritis, which is indicative of a common nature different-intensity manifestations of arthropathy in thick-borne borreliosis.

[Polymorphism of Fc gamma RIIIA-158F/V gene and promoter region of IL-10 gene in systemic lupus erythematosus in Kazakhs]. / Polimorfizm gena FcgammaRIIIA-158F/V i promotornoi oblasti gena IL-10 pri sistemnoi krasnoi volchanke u kazakhov.

AIM: To assess the role of allele polymorphism of genes Fc gamma RIII and IL-10 in systemic lupus erythematosus (SLR) in a homogeneous (stratified by nationality) Kazakh population sample. MATERIAL AND METHODS: Polymorphism of genes Fc gamma RIIIA and IL-10 was studied in 49 patients SLE patients and 81 healthy subjects (control group). Detection of two allele variants of gene Fc gamma RIIIA (alleles F and V) caused by point mutation in position 559 was performed by polymerase chain reaction (PCR) in the amplification refractory mutation system. Genetic changeability of IL-10 gene promotion site due to point mutation in position 627 (alleles 1 and 2) was investigated by polymorphism of restricted fragment lengths using restrictase RsaI. RESULTS: Significant differences in the distribution rates of genes Fc gamma RIIIA and IL-10 were revealed in SLE patients versus controls. Alleles F and -627A (1), including homozygous ones, are genes predisposing to development of SLE while variants of the markers V and -627 (2) are protecting genes. If a SLE patient's genotype combines alleles F of gene Fc gamma RIII and alleles 1 of gene IL-10 (F/F + 1/1), this patient has an 8 times higher risk to develop SLE. CONCLUSION: Polymorphism of genes Fc gamma RIIIA and IL-10 is associated with predisposition to development of SLE in Kazakh population. The analysis of combined genotypes of the studied genes suggests a synergic action of genes Fc gamma RIIIA and IL-10 on the risk to develop SLE.

[Analysis of the allele polymorphism of (CTG)n and (GAG)n triplet repeats in DM, DRPLA, and SCA1 genes in various populations of Russia]. / Analiz allel'nogo polimorfizma tripletnykh povtorov (CTG)n i (GAG)n v genakh DM, DRPLA i SCA1 v razlichnykh populiatsiiakh Rossii.

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.

[Effect of amiodarone on autonomic status and its efficacy in the treatment of different variants of paroxysmal atrial fibrillation]. / Vliianie amiodarona na vegetativnyi status i ego éffektivnost' v lechenii raznykh variantov paroksizmal'noi fibrilliatsii predserdii.

Association of autonomic status and efficacy of therapy with amiodarone was studied in 90 patients with paroxysmal atrial fibrillation of ischemic (n=45, mean age 62 years) and nonischemic (n=45, mean age 38 years) origin. Autonomic status was assessed by measurement of heart rate variability. Electrophysiological and echocardiographical studies were also conducted before and after 4 weeks of amiodarone therapy. Treatment with amiodarone was accompanied by substantial lowering of the tone of autonomic nervous system in patients with adrenergic type of paroxysmal atrial fibrillation while there was no dynamics of parasympathetic tone in patients with vagal or mixed types. Positive association between amiodarone therapy and decrease of left atrial dimension and improvement of left ventricular contractility was also observed. It was concluded that the use of amiodarone was justified in adrenergic but not in vagal or mixed variants of paroxysmal atrial fibrillation.

[Polymorphism of glutathione S-transferases M1 and T1 in several populations of Russia]. / Polimorfizm glutation-S-transferaz M1 i T1 v riade populiatsii Rossii.

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.

[Relations between ankylosing spondyloarthritis and HLA-B27 in various ethnic groups in Russia]. / Vzaimosviaz' ankiloziruiushchego spondiloartrita i HLA-B27 v nekotorykh étnicheskikh gruppakh Rossii.

AIM: To characterize relationship between prevalence of ankylosing spondylarthritis (ASA) and incidence rate of HLA-B27 in genotypically different ethnic groups of Russia with interpolation of the results to other populations. MATERIAL AND METHODS: 2287 individuals from genotypically different ethnic groups were examined in overall one-stage epidemiological trial. RESULTS: Prevalence of ASA in ethnic groups ranged from 0.2 to 2.0% while occurrence of HLA0B27--from 15 to 40%. Rate of correlation between the disease prevalence and incidence of B27 was 0.82. The equation for calculation of ASA incidence rate by HLA-B27 incidence was devised: AC(%) = -0.40 + 0.06x. CONCLUSION: In most world populations prevalence of ASA correlates with population frequency HLA-B27 though in some ethnic groups this correlation is absent. Consequently, ASA is genetically heterogenous.

[Normal polymorphism of the (CTG)n repeat in the myotonin protein kinase (DM) gene on chromosome 19q13.3 in Western European populations]. / Normal'nyi polimorfizm povtora (CTG)n v gene miotoninproteinkinazy (DM) na khromosome 19q13.3 v populiatsiiakh vostochnoi evropy.

Polymorphism of a highly polymorphic CTG repeat in the 3'-untranslated region of the myotonin protein kinase gene was analyzed in healthy people from several Eastern European populations (Russians, Moldovans, Belarussians, Komis, Chuvashes, Udmurts, Bashkirs, Tatars, Maris, and Mordovians). In total, 26 alleles of the CTG repeat were found, the repeat number ranging from 5 to 33 (alleles with six and seven repeats were not detected). The heterozygosity of individual populations varied from 61 to 91%. In the total sample combining all populations, the observed and expected heterozygosities did not differ (fixation index -0.0022) suggesting selective neutrality of the normal polymorphism of the CTG repeat in the myotonin protein kinase gene.