[Clinical and genetic description of neuronal ceroid lipofuscinosis 6 type in the yakut family]. / Kliniko-geneticheskoe opisanie neironal'nogo tseroidnogo lipofustsinoza 6 tipa v yakutskoi sem'e.

Neuronal ceroid lipofuscinosis type 6 (NCL 6) is a rare progressive neurodegenerative disease that belongs to the group of lysosomal storage diseases. A clinical and genetic description of NCL 6 in a Yakut family was carried out. The proband and her sibling showed characteristic clinical signs, including myoclonic epilepsy, ataxia, psychomotor regression, dementia, and visual impairment. The onset of the disease in the age range from 3-4 years. The disease is caused by the frameshift mutation c.396dupT (p.Val133CysfsTer18) in exon 4 of the CLN6 in a homozygous state, which was detected using targeted next generation sequencing. Diagnosis of NCL is difficult due to the pronounced genetic heterogeneity of the disease, as well as the similarity with other hereditary metabolic diseases in clinical manifestations. The method of DNA diagnostics of NCL type 6 using NGS and direct sequencing according to Sanger has been introduced into the practice of medical genetic counseling.

[Clinical and molecular-genetic characteristics of X-linked spinal-bulbar amyotrophy (Kennedy's disease) in the Sakha Republic (Yakutia)]. / Klinicheskaia i molekuliarno-geneticheskaia kharakteristika Kh-stseplennoi spinal'no-bul'barnoi amiotrofii Kennedi v Respublike Sakha (Iakutiia).

AIM: To perform a clinical-genealogical and molecular genetic analysis of X-linked spinal-bulbar amyotrophy (Kennedy's disease) in the Sakha Republic (Yakutia). MATERIAL AND METHODS: Six patients, aged from 30 to 60 years, from 4 unrelated Yakut families registered in the Republican genetics registry of hereditary and congenital abnormalities of the Sakha Republic were studied. The average age of onset was 45.1±4.4 years. A clinical-genealogical and molecular genetic methods were used. RESULTS AND CONCLUSION: The prevalence of spinal-bulbar amyotrophy Kennedy in the Republic of Sakha (Yakutia) is 1.3 per 100 thousand, among Yakut men is 2.8 per 100 thousand. Clinical manifestations of the disease in the patients included in the study were similar to those described previously in the literature. Patients underwent molecular genetic diagnosis in exon 1 of the androgen receptor (AR) gene. All of them carried the allele with more than 38 CAG repeats. There was an inverse correlation between the age at disease onset and the number of CAG-repeats. A method of DNA diagnosis of Kennedy's disease with visualization on an agarose gel has been introduced in genetic testing.

[Detection of novel genetic markers of susceptibility to preeclampsia based on an analysis of the regulatory genes in the placental tissue].

Regulatory single nucleotide polymorphisms (rSNPs) are the least-studied group of SNP; however, they play an essential role in the development of human pathology by altering the level of candidate genes expression. In this work, we analyzed 29 rSNPs in 17 new candidate genes associated with preeclampsia (PE) according to the analysis of the transcriptome in placental tissue. Three ethnic groups have been studied (yakut, russian, and buryat). We have detected significant associations of PE with eight rSNPs in six differentially expressed genes, i.e., rs10423795 in the LHB gene; rs3771787 in the HK2 gene; rs72959687 in the INHA gene; rs12678229, rs2227262, and rs3802252 in the NDRG1 gene; rs34845949 in the SASH1 gene; and rs66707428 in the PPP1R12C gene. We used a new approach to detecting genetic markers of multifactorial diseases in the case of PE based on a combination of genomic, transcriptomic, and bioinformatic approaches. This approach proved its efficiency and may be applied to detecting new potential genetic markers in genes involved in disease pathogenesis, which reduces missing heritability in multifactorial diseases.

A New Approach To the Diagnosis of Point Mutations in Native DNA Using Graphene Oxide.

Development of new methods for the diagnosis of point mutations is a pressing issue. We have developed a new approach to the design of graphene oxide-based test systems for the diagnosis of point mutations in native DNA. This new approach is based on the use of graphene oxide for the adsorption and quenching of fluorescently labeled primers in a post-amplification PCR mixture followed by detection of fluorescently labeled PCR products. It is possible to detect fluorescently labelled amplicons in the presence of an excess of primers in a PCR product solution due to the different affinities of single-stranded and double-stranded DNA molecules to graphene oxide, as well as the ability of graphene oxide to act as a quencher of the fluorophores adsorbed on its surface. The new approach was tested by designing a graphene oxide-based test system for the DNA diagnosis of the point mutation associated with the development of the 3M syndrome in Yakuts. The developed approach enables one to design graphene oxide-based test systems suitable for the diagnosis of any point mutations in native DNA.

[Haplotype Analysis of Oculopharyngeal Muscular Dystrophy (OPMD) Locus in Yakutia].

Oculopharyngeal muscular dystrophy (OPMD) is a hereditary neuromuscular disease with autosomal dominant and rarely with autosomal recessive inheritance types. This study included 50 patients with a clinical diagnosis of OPMD, 23 asymptomatic carriers of the mutation from 45 unrelated families, and 56 healthy relatives, as well as population samples of four ethnic groups of Yakutia: Yakuts, Evens, Evenks, Yukaghirs. It was found that the cause of OPMD development in all investigated families is the same increase in.GCN repeats to 14 copies in the PABPN1 gene. The molecular structure ofthe (GCN)14 mutant allele is (GCG)10(GCA)3GCG. The genetic variability of ten SNPs at the OPMD locus was studied in patient families and population samples. The haplotypes of OPMD were determined by a segregation analysis technique using the EM algorithm in the groups of patients, mutation carriers, and population samples. Only one haplotype of four SNPs (ATCG) linked with the (GCN)14 mutant allele was found in Yakuts and Russian patients and OPMD mutation carriers. Probably, this indicates the accumulation of mutations as a result of the founder effect.

[Population frequency and age of mutation G5741→A in gene NBAS which is a cause of SOPH syndrome in Sakha (Yakutia) Republic].

SOPH syndrome (Short stature with Optic nerve atrophy and Pelger­Huët anomaly syndrome, OMIM#614800) is an autosomal recessive hereditary disease characterized by the following main clinical symptoms: postnatal hypoplasia, proportionately short stature, facial dysmorphism, micromelia of feet and hands, limp and loose skin, optic nerve atrophy, and Pelger­Huët anomaly of neutrophils. For the first time, this disease was described in Yakuts. The molecular-genetic study showed that its cause in Yakuts is mutation G5741→A in gene NBAS. On the basis of disequilibrium analysis for linkage of ten microsatellite markers flanking the NBAS gene with the disease, the haplotype of the founder chromosome was determined. The age of the mutation in Yakutia was estimated to be about 804 ± 140 years. The frequency of heterozygous carriers of mutation G5741→A (R1914H) in gene NBAS was found, which averaged 13 per 1000 healthy Yakuts.

VKORC1 polymorphisms and warfarin maintenance dose in population of Sakha (Yakuts).

BACKGROUND: Vitamin K antagonists are effective in the prevention and treatment of thromboembolic disorders. Warfarin is one of the most widely prescribed vitamin K antagonists in the world [1, 2]. It has a narrow therapeutic range and a given dose may result in a large inter-individual variation of response. Insufficient dose may fail to prevent thromboembolism, while an overdose increases the risk of bleeding. Patient-specific factors (e.g., age, body size, race, concurrent diseases, and medications) explain some of the variability in warfarin dosage, but genetic factors influencing warfarin response explain a significantly higher proportion of this variability [3]. Molecular analysis of the gene that encodes the target enzyme vitamin K epoxide reductase complex 1 (VKORC1) strongly suggests that its genetic variations greatly affect the individual response to oral anticoagulants [4-7]. OBJECTIVE: To evaluate effects of VKORC1 polymorphisms on warfarin dose excess anticoagulation (INR >4.0) in the population of Sakha (S) patients. METHODS: 53 patients (29-women, 24-men) with atrial fibrillation (68%), congestive heart failure (60%), hypertension (49%) and cardiac valve replacement (26%) were recruited. The age range was 26-80 years, with a mean age of 62.87 ± 12.57 years.International normalized ratio and plasma warfarin concentrations were determined. Genotyping was carried out by RT-PCR (real-time PCR). The three genetic polymorphisms of the gene VKORC1 G3673A (rs9923231) were studied: normal (GG), heterozygous (GA) and homozygous (AA). Fisher exact probability test and chi-square test (with Yates correction) were applied to compare data among the AA and GG + GA groups; also Mann-Whitney test was used. RESULTS: The median maintenance daily dose of warfarin among AA carriers was 3.0 mg/day [1.25-7.5 mg], while in GG and GA patients it was 3.13 mg/day [1.88-7.92 mg]. The mean daily warfarin dosage was higher in GG and GA genotype carriers 4.05 mg/day (SD ± 1.7) than in patients with AA genotype 3.13 (SD ± 1.5). Differences are of borderline significance (p = 0.054). Of the 41 patients who required warfarin doses of less than 5 mg, 28 (63%) were found to be AA carriers and 14 (37%) were GG, GA carriers. Differences were not quite significant (p = 0.072). Among 31 homozygous polymorphism carriers 2 (4%) patients developed overanticoagulation (INR >4.0), while among 22 normal and heterozygous polymorphisms carriers only 3 (6%) patients developed overanticoagulation (INR >4.0). Differences were not statistically significant (p = 0.36). CONCLUSIONS: No significant association between VKORC1 polymorphisms and the frequency of excess anticoagulation (INR >4.0) was found. This may be explained by the number of cases included. AA polymorphisms compared to other polymorphisms shows borderline difference in the warfarin dose. The results can be used for the development of a pharmacogenetic-guided warfarin dosing algorithm.

EPIDEMIOLOGICAL FEATURES OF CHRONIC VIRUS HEPATITIS B AND C IN THE REPUBLIC SAKHA (YAKUTIA).

High disease burden of chronic virus hepatitis B and C of population in the Republic Sakha (Yakutia) is subject to referring it to endemic territories due to these infections. For a 15-year-old period the disease has been registered at higher rates in the Russian Federation.

[Analysis of mitochondrial 12S rRNA and tRNA(Ser(UCN)) genes in patients with nonsyndromic sensorineural hearing loss from various regions of Russia].

Mitochondrial DNA (mtDNA) mutations play an important role in etiology of hereditary hearing loss. In various regions of the world, patients suffer from nonsyndromic sensorineural hearing loss initiated by aminoglycoside antibiotics. Mutations that had been shown as pathogenetically important for hearing function disturbance were identified in mitochondrial 12S rRNA and tRNA(Ser(UCN)) genes while pathogenic role of several DNA sequences requires additional studies. This work presents the results of studying the spectrum of mutations and polymorphic variations in mtDNA genes 12S rRNA and tRNA(Ser(UGN)) in 410 patients with nonsyndromal sensoneural hearing impairment/loss from the Volga Ural region, St Petersburg, Yakutia, and Altai and in 520 individuals with normal hearing, which represent several ethnic groups (Russians, Tatars, Bashkirs, Yakuts, Altaians) residing in the Russian Federation. Pathogenetically significant mutation A1555G (12S rRNA) was found in two families (from Yakutia and St Peresburg) with hearing loss, probably caused by treatment with aminoglucosides, and in the population sample of Yakuts with a frequency of 0.83%. Further research is needed to confirm the role in hearing impairment of mutations 961insC, 961insC(n), 961delTinsC(n), T961G, T1095C (12S rRNA) and G7444A, A7445C (tRNA(Ser(UGN revealed in the patients. In addition, in the patients and the population groups, polymorphic mt DNA variants were detected, which are characteristic also of other Eurasian populations both in spectrum and frequency.

[Hereditary diseases among Yakuts].

Several forms of pathologies, referred to as Yakut hereditary diseases, have been distinguished on the basis of the results of genetic epidemiological studies of Mendelian diseases in the population of the Republic of Sakha (Yakutia): spinocerebellar ataxia type I, myotonic dystrophy, oculopharyngeal muscular dystrophy, hereditary enzymopenic methemoglobinemia, and 3-M syndrome. These diseases are characterized by a high prevalence among Yakuts as compared to their global incidence in the. Data on the molecular nature of mutations in genes responsible for these hereditary diseases are presented.

[Connexin gene 26 (GJB2) mutations in patients with hereditary non-syndromic sensorineural loss of hearing in the Republic of Sakha (Yakutia)].

The aim of the study was to elucidate the causes of hereditary non-syndromic loss of hearing, a frequent monogene pathology in the Republic of Sakha (Yakutia). A search for mutations in the coding sequence of the connexin 26 gene gap-junction B2 (GJB2) was undertaken in 79 members of 65 unrelated families with the diagnosis of grade III-IV non-syndromic bilateral sensorineural loss of hearing. Five recessive mutations (35delG, V371, 312-326del14, 333-334delAA, R127H) and three polymorphic variants (V271, M34T, E114G) were identified in Yakut patients. Mutations 35delG (41.7%), 312-326dell4 (4.2%), and 333-334delAA (4.2%) were found in Caucasian patients (Russians, Ukrainians, Inguish). Yakuts were carriers of mutations 35delG (2.1%), V371 (2.1%), R127H (1.0%) and sequence variants V271 (6.3%), M34T (1.0%), E114G (1.0%). GJB2 mutations were identified in 50.1% of the Caucasian patients and in 7.2% of the Yakut patients. The low frequency of GJB2 mutations in Yakuts with non-syndromic sensorineural loss of hearing testifies to the presence of mutations of other genes controlling sound perception in this population.

[The origin of Yakuts: analysis of Y-chromosome haplotypes].

Gene pool structure of Sakha Republic (Yakutia) native population has been studied: we defined composition and frequencies of Y-chromosome haplogroups for Yakuts. Six haplogroups: C3 x M77, C3c, N*, N2, N3a and R1a1 have been revealed in Yakut gene pool. A greater part of Y-chromosome in Yakut population belongs to N3a haplogroup (89%). All investigated Yakut population samples have low values of gene diversity, calculated based on haplogroup frequencies. Gene differentiation of the investigated samples estimated using the analysis of molecular variance (AMOVA) by two marker systems (haplogroup frequencies and microsatellite haplotypes of Y-chromosome) revealed a portion of interpopulation differences amounting to 0.24 and 2.85%, respectively. Frequencies and molecular phylogeny of YSTR-haplotypes were revealed for N3a haplogroup of Y-chromosome. Altogether forty haplotypes were found in Yakuts. Evenks and Yakuts are characterized by overlapping and very specific spectrum of N3a haplotypes, which is not typical for other Siberian ethnic groups. Cluster analysis of populations by N3a YSTR-haplotypes shows Yakut isolation from Turkic-speaking populations in the South Siberia. Genetic diversity generation time for a specific spectrum of Yakut haplotypes was estimated as 4.45 +/- 1.96 thousand years. As opposed to the data on mtDNA, the obtained results give an evidence for significant contribution of a local palaeolithic component into Y-chromosomal Yakut gene pool. Ethnogenetic reconstruction of the present picture of genetic diversity in N3a haplogroup in the territory of Siberia is under consideration.

[The clinical-genealogic and molecular-genetic characteristics of oculopharyngeal muscular dystrophy in the Republic of Sakha (Yakutia)].

The clinical-genealogic and molecular-genetic investigation of oculopharyngeal muscular dystrophy (OPMD) in the Republic of Sakha (Yakutia) was performed. It was investigated 33 unrelated Yakut families with 38 patients and 2 russian families with 2 patients and 59 their healthy relatives as well. The high clinical polymorphism of disease was found in patients with OPMD. The mutation in exon 1 of the PABPN1 gene resulting in the expansion of GCG-repeats up to 10 is revealed. Using direct sequencing of the PABPN1 gene in 17 families (16 Yakut, 1 Russian), we identified a type of this mutation as an insertion of 4 GCG-repeats. Frequency of OPMD in the Yakut population is 1:11 680 that is 10-20 times higher comparing to european populations. This is a first report on the patients with OPMD from the Republic of Sakha with diagnosis confirmed by molecular-genetic analysis.

[Genetic demographic description of the Ust-Aldan rural population of Sakha Republic (Yakutia): ethnic, sex, and age compositions, vital statistics, and surname structure]. / Genetiko-demograficheskoe opisanie selskogo naseleniia Ust'-Aldanskogo ulusa respubliki Sakha (Iakutiia): natsional'nyi i polovovozrastnoi sostav, vital'nye statistiki, famil'naia struktura.

Information on the sex, age, and ethnic compositions; reproductive parameters; intensity of natural selection (Crow's indices); and surname diversity of three rural populations (the Byadi, Dyupsya, and Cheriktey villages) of the Ust-Aldan ulus (district) of Sakha Republic (Yakutia) has been analyzed. The rural Yakut population of the Ust-Aldan ulus is demographically young (the mean age 25-31 years) and characterized by low outbreeding, unfavorable sex ratio in both prereproductive and reproductive ages, and high fertility (3.58-5.45 children surviving until the reproductive age per woman that has completed the reproductive period), although the actual reproductively active period is shorter than half its physiological duration. In the structure of total selection, the differential-fertility component is considerably greater than the differential-mortality component (Itot = 0.625, Im = 0.093, and If = 0.487). In the villages studied, some surnames are accumulated (45-65% of the population have five most frequent surnames), which determines the low surname diversity (alpha = 11.62-25.19) and high random isonymy (Ir = 0.0391-0.0823).

[Genetic demographic description of the Ust-Aldan rural population of Sakha Republic (Yakutia): migrations and marriage structure]. / Genetiko-demograficheskoe opisanie Ust'-Aldanskogo ulusa respubliki Sakha (Iakutiia): migratsionnye protsessy, brachnaia struktura.

Migrations, dynamics of the gametic structure of rural populations, and marriage structure with respect to birthplaces and inbreeding estimated from isonymy have been studied in the Ust-Aldan ulus (administrative district) of Sakha Republic (Yakutia). The villages studied (Byadi, Dyupsya, and Cheriktey) are characterized by intense migration; however, the migration radius is small (most migrations occur within the district). The rural populations studied differ in the intensities and directions of gamete flows and their dynamics. There is no substantial gamete flow into the Ust-Aldan population from outside Sakha Republic. About 50% of marriages contracted in this population are homolocal (between residents of the same district); the endogamy is low (15%). In most cases of heterolocal marriages (contracted between residents of different districts), one of the spouses is a local resident. The inbreeding estimated from isonymy is FTT = 0.002930 in Yakuts; it is mainly accounted for by the nonrandom component (FIS = 0.002232 and FST = 0.000700).

[Population study of frequency of methylenetetrahydrofolate reductase C677T gene polymorphism in Yakutia]. / Populiatsionnoe issledovanie chastoty polimorfizma C677T gena metilentetragidrofolat-reduktazy v Iakutii.

The enzyme methylenetetrahydrofolate reductase (MTHFR) catalyzes synthesis of 5'-methylenehydrofolate, which is the methyl donor for the conversion of homocysteine to methionine. According to the numerous literature data, polymorphic variant of the MTHFR-encoding gene, C677T, is associated with hyperhomocysteinemia, vascular pathologies, neural tube defects, dementia, perinatal mortality, mental disorders, long-term neurodegenerative disorders, lens displacement, arachnodactyly, and venous thromboses. The present study was focused on the analysis of the C677T polymorphism (missence mutation leading to the replacement of cytosine by thymine at position 677) of the MTHFR gene in three indigenous populations of the Republic of Sakha (Yakutia), living in the settlements of Cheriktei, Byadi, and Dyupsya. Comparison of the genotype and allele frequencies revealed no substantial differences between the three Yakut populations, as well as between Yakuts and other Mongoloid ethnic groups.

[Analysis of mitochondrial DNA haplotypes in yakut population]. / Analiz linii mitokhondrial'noi DNK v populiatsii iakutov.

To study the mitochondrial gene pool structure in Yakuts, polymorphism of mtDNA hypervariable segment I (16,024-16,390) was analyzed in 191 people sampled from the indigenous population of the Sakha Republic. In total, 67 haplotypes of 14 haplogroups were detected. Most (91.6%) haplotypes belonged to haplogroups A, B, C, D, F, G, M*, and Y, which are specific for East Eurasian ethnic groups; 8.4% haplotypes represented Caucasian haplogroups H, HV1, J, T, U, and W. A high frequency of mtDNA types belonging to Asian supercluster M was peculiar for Yakuts: mtDNA types belonging to haplogroup C, D, or G and undifferentiated mtDNA types of haplogroup M (M*) accounted for 81% of all haplotypes. The highest diversity was observed for haplogroups C and D, which comprised respectively 22 (44%) and 18 (30%) haplotypes. Yakuts showed the lowest genetic diversity (H = 0.964) among all Turkic ethnic groups. Phylogenetic analysis testified to a common genetic substrate of Yakuts, Mongols, and Central Asian (Kazakh, Kyrgyz, Uigur) populations. Yakuts proved to share 21 (55.5%) mtDNA haplogroups with the Central Asian ethnic groups and Mongols. Comparisons with modern paleo-Asian populations (Chukcha, Itelmen, Koryaks) revealed three (8.9%) haplotypes common for Yakuts and Koryaks. The results of mtDNA analysis disagree with the hypothesis of an appreciable paleo-Asian contribution to the modern Yakut gene pool.

[MtDNA and Y-chromosome lineages in the Yakut population]. / Linii mtDNK i Y-khromosomy v populiatsii iakutov.

The structure of female (mtDNA) and male (Y-chromosome haplotypes) lineages in the Yakut population was examined. To determine mtDNA haplotypes, sequencing of hypervariable segment I and typing of haplotype-specific point substitutions in the other parts of the mtDNA molecule were performed. Y haplogroups were identified through typing of biallelic polymorphisms in the nonrecombining part of the chromosome. Haplotypes within haplogroups were analyzed with seven microsatellite loci. Mitochondrial gene pool of Yakuts is mainly represented by the lineages of eastern Eurasian origin (haplogroups A, B, C, D, G, and F). In Yakuts haplogroups C and D showing the total frequency of almost 80% and consisting of 12 and 10 different haplopypes, respectively, were the most frequent and diverse. The total part of the lineages of western Eurasian origin ("Caucasoid") was about 6% (4 haplotypes, haplogroups H, J, and U). Most of Y chromosomes in the Yakut population (87%) belonged to haplogroup N3 (HG16), delineated by the T-C substitution at the Tat locus. Chromosomes of haplogroup N3 displayed the presence of 19 microsatellite haplotypes, the most frequent of which encompassed 54% chromosomes of this haplogroup. Median network of haplogroup N3 in Yakuts demonstrated distinct "starlike phylogeny". Male lineages of Yakuts were shown to be closest to those of Eastern Evenks.

[Genetic peculiarity of the yakut population from the autosomal loci data]. / Geneticheskoe svoeobrazie naseleniia Iakutii po dannym autosomnykh lokusov.

The autosomal gene pool of Yakuts was analyzed with a panel of polymorphic Alu insertions. The observed allele frequencies were typical for other Asian ethnic groups. Genetic differentiation of three Yakut populations was relatively high, 2%. East Siberian ethnic groups were shown to have a common gene pool and to experience no intense gene flow from other populations. Development of the Yakut gene pool was assumed to involve no substantial genetic effect of neighboring populations. The results fit both autochthonous and southern origin hypotheses.