Hereditary deafness in Kirov oblast: a genetic epidemiological study

The results of a genetic epidemiological study of hereditary deafness (HD) in ten raions (districts) of Kirov oblast (administrative region), Russia, are presented. A total of 122 075 people have been examined. Segregation analysis of all families with diagnosed HD has demonstrated a good fit to either the autosomal dominant (AD) or autosomal recessive (AR) mode of inheritance. The total prevalence rates of AD and AR HDs, as well as the specific prevalence rates of nonsyndromic and syndromic forms of HD, have been calculated for the population often raions. The HD prevalence rate in Kirov oblast has been found to be 1 : 1043 people (1 : 1453 and 1 : 3699 for the nonsyndromic and syndromic forms, respectively). This value has been found to vary in different raions, which is explained by differences in the genetic subdivision levels of the populations studied; the correlation coefficient between the HD load and random inbreeding (F(ST)) in district populations is r = 0.81 +/- 0.22. The diversity of syndromic hearing disorders is described.     

The load and diversity of hereditary diseases in four raions of Rostov oblast

The results of a medical genetic survey of the population of four raions (176535 individuals) of Rostov oblast (Dubovsky, Zimovnikovsky, Myasnikovsky, and Krasnosulinsky raions) are presented. The load of autosomal dominant (AD), autosomal recessive (AR), and X-linked hereditary diseases for urban and rural population was calculated, and the diversity of monogenic hereditary diseases (MHD) was reviewed. The nosological spectrum of MHD constituted 117 diseases (63 diseases with AD inheritance; 38, with AR inheritance; and 16, with X-linked inheritance). The analysis showed that the incidence of MHD among the population of Rostov oblast was 1: 336. Considerable differentiation in the prevalence rates of MHD (AD, AR, and X-linked pathologies) among certain raions was revealed.     

Epidemiology of monogenic hereditary diseases in Rostov oblast: Population dynamic factors determining the differentiation of the load of hereditary diseases in eight districts

Analysis of the diversity of monogenic hereditary diseases in eight raions (districts) of Rostov oblast (region) of Russia (Tsimlyansk, Volgodonskoi, Tselina, Egorlykskaya, Millerovo, Tarasovskaya, Rodionovo-Nesvetaiskaya, and Matveevo-Kurgan raions) has been summarized. The total sample size was 320925 subjects. The spectrum of hereditary diseases detected in the eight districts comprises 187 diseases, including 99 autosomal dominant (AD), 72 autosomal recessive (AR), and 16 X-linked diseases. The mean prevalence rate of each disease in the total population has been calculated. Accumulation of individual diseases in different regions of Rostov oblast has been calculated; the disease accumulation has been compared with that in some populations of Russia examined earlier. Cluster analysis using the data on the frequencies of genes of hereditary diseases has shown the gene geographic position of the Rostov oblast population among the following ethnic populations of Russia: Russians (Kostroma, Kirov, and Rostov oblasts and Krasnodar krai), Chuvashes (Chuvashia), Adygeans (Adygea), Maris (Marii El), and Udmurts (Udmurtia).     

Prevalence and Molecular Genetic Typing of Nonsyndromic Sensorineural Deafness in Chuvash Republic

Summarized genetic epidemiological characteristics of nonsyndromic sensorineural deafness in six raions of Chuvash Republic (Cheboksary, Kanash, Morgaushi, Tsivil'sk, Mariinski Posad, and Alatyr') are presented. A total of 264419 individuals were examined. Forty-five families (60 affected individuals) with autosomal recessive (AR) and 8 families (18 affected individuals) with autosomal dominant (AD) nonsyndromic sensorineural deafness (NSSD) were identified. The load of AD and AR NSSD in the raions examined was estimated. A correlation between the distribution of AR NSSD and genetic drift was demonstrated. Furthermore, the load of AR NSSD was substantially higher in the regions with higher differentiation level. The Spearman's correlation coefficient value was 0.87. Typing of the 35delG mutation in the gene for connexion 26 was carried out in 34 patients from 26 families with AR NSSD. Comparative estimates of the NSSD prevalence in a number of Russian populations were performed.     

Prevalence and molecular-genetic typing of nonsyndromal neurosensory deafness in the Chuvash Republic

Summarized genetic epidemiological characteristics of nonsyndromic sensorineural deafness in six raions of Chuvash Republic (Cheboksary, Kanash, Morgaushi, Tsivil'sk, Mariinski Posad, and Alatyr') are presented. A total of 264,419 individuals were examined. Forty-five families (60 affected individuals) with autosomal recessive (AR) and 8 families (18 affected individuals) with autosomal dominant (AD) nonsyndromic sensorineural deafness (NSSD) were identified. The load of AD and AR NSSD in the raions examined was estimated. A correlation between the distribution of AR NSSD and genetic drift was demonstrated. Furthermore, the load of AR NSSD was substantially higher in the regions with higher differentiation level. The Spearman's correlation coefficient value was 0.87. Typing of the 35delG mutation in the gene for connexion 26 was carried out in 34 patients from 26 families with AR NSSD. Comparative estimates of the NSSD prevalence in a number of Russian populations were performed.     

Epidemiology of monogenic hereditary diseases in Rostov oblast: Population dynamic factors determining the differentiation of the load of hereditary diseases in eight districts

A genetic epidemiological study has been carried out in eight raions (districts) of Rostov oblast (region) of Russia: Tsimlyansk, Volgodonskoi, Tselina, Egorlykskaya, Millerovo, Tarasovskaya, Rodionovo-Nesvetaiskaya, and Matveevo-Kurgan raions. The population structure (the parameters of the isolation by distance model, ethnic assortative marriage, random inbreeding (F _ST), endogamy index, and ie) and the genetic demographic characteristics of the regional population (vital statistics, Crow’s index, and its components) have been analyzed. The total sample size was 320 925 subjects (including 114 106 and 206 816 urban and rural residents, respectively). The load of the main types of Mendelian diseases (autosomal dominant (AD), autosomal recessive (AR), and X-linked diseases) has been calculated for the total sample from eight districts and separately for the urban and rural populations. Substantial differences between individual districts in the AD and AR genetic loads have been found, especially upon separation into urban and rural samples. The results of correlation analysis suggest that migration and genetic drift are the main factors of genetic differentiation of populations with respect to the prevalence of hereditary diseases.     

Analysis of Diversity of Autosomal Recessive Diseases in Populations of Russia

The diversity of autosomal recessive (AR) diseases was studied in six Russian regions: the Kirov, Kostroma, and Bryansk oblasts; Adygea Republic; Krasnodar krai, and Marii El Republic (in the latter region, the Mari and Russian ethnic groups were studied separately). In total, more than 1.5 million people were studied. The spectrum of the AR diseases included 101 nosological forms; the total number of the affected was 942. For all diseases, the prevalence rate in the region where they were found and the mean prevalence rate in the total population studied were calculated. Only seven AR diseases had prevalence rates of 1 : 50000 or higher; however, this group contained about 50% of the patients. About half of the AR diseases (66) had an extremely low prevalence rate (1 : 877483). Eleven diseases exhibit local accumulation. Accumulation of some or other diseases was only observed in four out of seven populations studied (Marii El, Adygea, and the Kirov and Bryansk oblasts). To determine the cause of the local accumulation of some diseases in populations, correlation analysis of the dependence of accumulation of hereditary diseases on the genetic structure of the populations studied was performed. The accumulation coefficients for AR and autosomal dominant (AD) diseases and the mean values of random inbreeding (F _st) in individual districts were calculated for all populations studied. The coefficients of the Spearman rank correlation between the accumulation coefficient and random inbreeding (F _st) were 0.68 and 0.86 for the AD and AR diseases, respectively. The correlation between the accumulation of AD and AR diseases was 0.86. The relationships found indicate that the diversity of AD and AR diseases, as well as the genetic load, distinctly depended on the population genetic structure and were largely determined by genetic drift.     

Genetic epidemiological study of Bashkortostan Republic: The diversity of monogenic hereditary diseases in five districts

The diversity of monogenic hereditary diseases (HDs) (autosomal dominant (AD), autosomal recessive (AR), and X-linked diseases) has been studied in five districts of Bashkortostan Republic: Burzyanskii, Abzelilovskii, Baimak, Salavatskii, and Arkhangel’skoe raions. The spectrum of HDs comprised 144 diseases, including 83, 48, and 13 AD, AR, and X-linked diseases. Most of them were found earlier during studies in ten other regions of Russia (Kirov, Kostroma, Tver’, Bryansk, and Rostov oblasts, and Krasnodar krai, and the republics of Adygea, Marii El, Udmurtia, and Chuvashia). Foci of local accumulation of some AD, AR, and X-linked diseases have been found in individual districts. Data on the gene frequencies for the HDs have been used for cluster analysis, which has shown the gene geographic position of Bashkirs among nine ethnic populations of Russia: Russians (Kostroma, Kirov, and Rostov oblasts and Krasnodar krai), Chuvashes (Chuvashia), Adygeans (Adygea), Maris (Marii El), Udmurts (Udmurtia), and Bashkirs (Bashkortostan).     

Analysis of diversity of autosomal-recessive diseases in Russian populations]

The diversity of autosomal recessive (AR) diseases was studied in six Russian regions: the Kirov, Kostroma, and Bryansk oblasts; Adygea Republic; Krasnodar krai, and Marii El Republic (in the latter region, the Mari and Russian ethnic groups were studied separately). In total, more than 1.5 million people were studied. The spectrum of the AR diseases included 101 nosological forms; the total number of the affected subjects was 942. For all diseases, the prevalence rate in the region where they were found and the mean prevalence rate in the total population studied were calculated. Only seven AR diseases had prevalence rates of 1:50,000 or higher; however, this group contained about 50% of the patients. About half of the AR diseases (66) had an extremely low prevalence rate (1:877,483). Eleven diseases exhibit local accumulation. Accumulation of some or other diseases was only observed in four out of seven populations studied (Marii El, Adygea, and the Kirov and Bryansk oblasts). To determine the cause of the local accumulation of some diseases in populations, correlation analysis of the dependence of accumulation of hereditary diseases on the genetic structure of the populations studied was performed. The accumulation coefficients for AR and autosomal dominant (AD) diseases and the mean values of random inbreeding (Fst) in individual districts were calculated for all populations studied. The coefficients of the Spearman rank correlation between the accumulation coefficient and random inbreeding (Fst) were 0.68 and 0.86 for the AD and AR diseases, respectively. The correlation between the accumulation of AD and AR diseases was 0.86. The relationships found indicate that the diversity of AD and AR diseases, as well as the genetic load, distinctly depended on the population genetic structure and were largely determined by genetic drift.     

Genetic structure of the Udmurt population

Integrated study of the genetic structure of the Udmurt population with respect to different genetic systems has been performed. Data on the genes of genetic diseases, abiotic parameters analyzed by population statistic methods, and DNA polymorphism are summarized. The populations of six raions (districts) of Udmurt Republic (the Mozhga, Malaya Purga, Sharkan, Debesy, Igra, and Glazov raions) have been studied. The total population studied was 267 655 people (an urban population of 150 119 people and a rural population of 117 536 people), including 155 346 Udmurts. The population structure has been studied in six districts on the basis of the vital statistics, Crow’s indices, Malecot’s isolation by distance parameters, ethnically assortative marriage parameters, endogamy indices, inbreeding-endogamy (ie) indices, and frequencies of the genotype and allele frequencies of four DNA markers (17 alleles). The prevalences of hereditary diseases have been calculated for different population groups: urban and rural populations, Udmurts and other ethnic groups. These groups, especially the urban and rural populations, substantially differed from one another in the prevalences of autosomal dominant (AD) and autosomal recessive (AR) diseases. The correlation between the prevalence of AD and AR diseases and the ie index is positive and significant. The spectrum of hereditary diseases detected in six districts of Udmurtia comprises 149 diseases (80, 57, and 12 AD, AR, and X-linked diseases, respectively). Accumulation of individual diseases in districts of Udmurtia and accumulation of diseases in Udmurtia as compared to regions studied earlier has been found. Cluster analysis of the frequencies of genes of AD and AR diseases and DNA markers has determined the gene geographic position of Udmurts.     

A medico-genetic description of inhabitants of two regions of the Kransnodar Krai]

The spectrum and prevalence rate of hereditary pathology in Kanevskii and Bryukhovetskii raions (districts) of Krasnodar krai (territory) were analyzed. The total size of the studied population was 145,937. The prevalence rate of monogenic hereditary pathology was estimated. This value was 1.08 +/- 0.08, 0.72 +/- 0.07, and 0.20 +/- 0.06 per 1000 people for autosomal dominant (AD), autosomal recessive (AR), and X-linked (XL) recessive diseases, respectively. Forty-two AD (158 affected persons in 82 families), 32 AR (105 affected persons in 82 families), and 6 XL disease entities (13 affected persons in 8 families) were found. A slight genetic subdivision was found in the populations of Kanevskii and Bryukhovetskii raions. However, it was not found to affect the prevalence of hereditary pathology.     

Genetic structure of the Udmurt population

Integrated study of the genetic structure of the Udmurt population with respect to different genetic systems has been performed. Data on the genes of genetic diseases, abiotic parameters analyzed by population statistic methods, and DNA polymorphism are summarized. The populations of six raions (districts) of Udmurt Republic (the Mozhga, Malaya Purga, Sharkan, Debesy, Igra, and Glazov raions) have been studied. The total population studied was 267,655 people (an urban population of 150,119 people and a rural population of 117,536 people), including 155,346 Udmurts. The population structure has been studied in six districts on the basis of the vital statistics, Crow's indices, Malecot's isolation by distance parameters, ethnically assortative marriage parameters, endogamy indices, inbreeding-endogamy (ie) indices, and frequencies of the genotype and allele frequencies of four DNA markers (17 alleles). The prevalences of hereditary diseases have been calculated for different population groups: urban and rural populations, Udmurts and other ethnic groups. These groups, especially the urban and rural populations, substantially differed from one another in the prevalences of autosomal dominant (AR) and autosomal recessive (AR) diseases. The correlation between the prevalence of AD and AR diseases and the ie index is positive and significant. The spectrum of hereditary diseases detected in six districts of Udmurtia comprises 149 diseases (80, 57, and 12 AD, AR, and X-linked diseases, respectively). Accumulation of individual diseases in districts of Udmurtia and accumulation of diseases in Udmurtia as compared to regions studied earlier has been found. Cluster analysis of the frequencies of genes of AD and AR diseases and DNA markers has determined the gene geographic position of Udmurts.     

Population genetics of hereditary diseases in the child population of the Republic of Bashkortostan, Chuvashia, and Udmurtia

The results of integrated study of the genetic structure and prevalence of monogenic hereditary diseases (MHDs) in the child population of three republics of Russia are summarized. Eight raions (districts) of the Republic of Bashkortostan and six districts of each Republic of Chuvashia and Republic of Udmurtia has been surveyed. The total population surveyed was 782184 people, with children accounting for 24.67% of them (192992 children). The loads of autosomal dominant (AD), autosomal recessive (AR), and X-linked MHDs have been calculated separately for urban and rural populations; differences between individual populations in the MHD load have been found. The differentiation of subpopulations with respect to MHD prevalence is explained by differences in the degree of subdivision. The MHD spectrum in the child population of the three republics comprises 222 disease entities, including 121 AD, 83 AR, and 18 X-linked diseases. Group of highly prevalent MHDs in regional child populations have been determined. The mean fitness of MHD patients in Bashkortostan has been calculated; it is 0.87, 0.04 and 0.16 for AD, AR, and X-linked diseases, respectively. Analysis has demonstrated that the prevalence rates of MHDs in the child populations of the republics of Chuvashia, Udmurtia, and Bashkortostan are 1, 1.2, and 1.4%, respectively.     

Genetic epidemiological study of monogenic hereditary diseases in the Republic of Tatarstan: Population dynamic factors determining the differentiation of the load of hereditary diseases in five districts

A genetic epidemiological study has been performed in five districts of the Republic of Tatarstan, Russia: Arsky, Atninsky, Kukmorsky, Buinsky and Drozhzhanovsky raions. The total size of the population surveyed is 188397 people. Tatars accounted for 77.13% of the population analyzed (145466 people) and were represented by two main ethnic groups: Kazan Tatars and Mishars. The medical genetic study encompassed the total population of the districts, irrespective of ethnicity, and was carried out according to the standard protocol developed in the Laboratory of Genetic Epidemiology of the Research Center for Medical Genetics of the Russian Academy of Medical Sciences. After segregation analysis, the prevalence rates of the main types of monogenic hereditary disorders (MHDs), i.e., autosomal dominant (AD), autosomal recessive (AR), and X-linked diseases, have been calculated for the total population of the five districts and for Tatars alone. The prevalence rates of AD, AR, and X-linked diseases considerably vary in different subpopulations. The largest difference in the MHD prevalence rate has been found between the rural and urban populations. The overall prevalence rate of MHDs was one patient per 293 urban residents and populations and one patient per 134 rural residents, with a wide variation between subpopulations, from 1: 83 people in the rural population of Atninsky raion to 1: 351 people in the town of Kukmor. Comparison of the MHD prevalence rate in Tatars with those in populations surveyed earlier has shown that the characteristics of the load of MHDs in the Tatar population are similar to those in some districts of the republics of Bashkortostan, Udmurtia, Mari El, and Chuvachia. In Russian populations of European Russia, the MHD prevalence rates are substantially lower. Correlation analysis has shown high (r = 0.5?C0.9) significant correlations between the local inbreeding (a), the im index, the random inbreeding (F _ST), and the AD and AR prevalence rates in the Tatar population. This analysis has demonstrated that genetic drift is the main population dynamic factor determining the MHD load in the Tatar population.     

Genetic Divergence and Similarity of Introduced Populations of European Beaver (Castor fiber L., 1758) from Kirov and Novosibirsk Oblasts of Russia

Potential factors were analyzed that affected the formation of gene pools of two introduced beaver populations founded in the 1940s–1950s by releasing beavers from Voronezh oblast and Belarus into rivers of the Kirov and Novosibirsk oblasts. The populations from these two regions were shown to differ in four allozyme loci (Ahd-2, Gpi, Es-5, and Dia-2). Within Kirov oblast, the samples from three tributaries of the Vyatka River differed in three other loci (Ck-1, Gp-9, and Trf). It is suggested that these features of the allele distribution at these loci are explained by the history of the introduced populations, hybridization between beavers from Voronezh oblast and Belarus, and founder effect during the subsequent artificial and spontaneous migration. Generally, genetic differences between the populations in all studied loci were very small: D = 0.02 between populations from different regions and D = 0.01 between populations from the tributaries of third-order rivers of the Kirov oblast. At the same time, disequilibrium was detected for ten polymorphic loci in the combined sample from the populations of Kirov oblast, which indicates the existence of interpopulation heterogeneity at the level of local populations of fourth- and fifth-order rivers. The unexpected finding of a genetic similarity between one studied individual of Tuvinian beaver subspecies (Castor fiber tuvinicus) and C. f. orientoeuropeas was recorded.     

Diversity and Prevalence of Hereditary Diseases among Nogais of the Karachay-Cherkess Republic

The diversity and prevalence of hereditary diseases (HDs) among Nogais of the Karachay-Cherkess Republic (KChR) are described. The size of the surveyed KChR population was 387231 individuals, including 3.81% Nogais (14741 individuals). We revealed 36 nosological forms of HDs (110 patients from 81 families): 22 with autosomal dominant (AD) inheritance, 10 with autosomal recessive (AR) inheritance, and 4 with X-linked inheritance. The prevalence of HDs in Nogais was 1: 134. The features of HD diversity in Nogais were determined in comparison with the previously surveyed populations of Russia. The accumulation of Ehlers–Danlos syndrome (1: 388), AD amelogenesis imperfecta (1: 3685), AD ichthyosis (1: 4914), AR nonsyndromic mental retardation (1: 1340), AR Gilbert syndrome (1: 4914), and X-linked inherited deficit of glucose-6-dehydrogenase (1: 1774 males) was established. The analysis of heterozygous carriage of mutations “major” for Russia in the genes of the four following AR diseases in 118 unrelated clinically healthy Nogais (236 analyzed chromosomes) was performed: cystic fibrosis (13 mutations in the CFTR gene: CFTRdele2,3 (21 kb), F508del, I507del, 1677delTA, 2184insA, 2143delT, 2183AA>G, 2184delA, 394delTT, 3821delT, L138ins, E92K, W1282X); phenylketonuria (six frequent mutations in the PAH gene: R261X, R408W, R413P, F331S, P211T, P211L); nonsyndromic sensorineural hearing loss (35delG mutation in the GJB2 gene); and Gilbert syndrome (an increase in the number of TA repeats in the UGT1A1 gene). Allelic specificity for all studied genes in the Nogai people was revealed.     

Surname distribution and random inbreeding in Kirov oblast

Data on surname distribution in 24 raions of Kirov oblast with a total adult population of more than 785000 people were used to calculate the random inbreeding values for populations of the district and rural municipality levels and analyze the geographic distributions of these values. The data have been compared with the results of studies carried out in the 1980s.     

Diversity in autosomal-dominant diseases in the Russian population

Results of 20-year studies on the diversity of autosomal dominant (AD) diseases are summarized. The studies were carried out in six regions of Russia: Kirov, Kostroma, and Bryansk oblasts; Krasnodar krai; and Adygea and Marii El republics. A total of 1.5 million subjects from 44 raions (districts) were studied. In the populations studied, 144 AD diseases were found; the total number of affected persons was 1723. The prevalence rate in the region where the disease was found and the average prevalence rate in the total population studied were calculated for each disease. Only 11 AD diseases had prevalence rates of 1:50,000 or higher. About half of AD diseases (64) had a very low prevalence rate (1:861,408). However, most cases (about 70% of the affected persons) were accounted for by more frequent diseases. Forty-six diseases exhibited local accumulation. The AD mutation rate was estimated by direct calculation. This rate was 0.542 x 10(-6) per gamete per generation.     

Diversity of Autosomal Dominant Diseases in Populations of Russia

Results of 20-year studies on the diversity of autosomal dominant (AD) diseases are summarized. The studies were carried out in six regions of Russia: Kirov, Kostroma, and Bryansk oblasts; Krasnodar krai; and Adygea and Marii El republics. A total of 1.5 million subjects from 44 raions (districts) were studied. In the populations studied, 144 AD diseases were found; the total number of affected persons was 1723. The prevalence rate in the region where the disease was found and the average prevalence rate in the total population studied were calculated for each disease. Only 11 AD diseases had prevalence rates of 1 : 50 000 or higher. About half of AD diseases (64) had a very low prevalence rate (1 : 861 408). However, most cases (about 70% of the affected persons) were accounted for by more frequent diseases. Forty-six diseases exhibited local accumulation. The AD mutation rate was estimated by direct calculation. This rate was 0.542 × 10^–6per gamete per generation.     

Integrated population genetic and medical genetic study of two raions of the Tver oblast

An integrated medical genetic an population genetic study has been performed in two raions (administrative districts) of the Tver oblast (region) of Russia: the Udomlya raion located in the zone affected by the Kalininskaya Nuclear Power Plant and the Ostashkov raion, which served as a control district. No significant differences has been found with respect to the genetic parameters studied. The values of these parameters in the populations of the town of Udomlya, the town of Ostashkov, the Udomlya raion, and the Ostashkov raion, respectively, are the following: random inbreeding, 0.00006, 0.00011, 0.000167, and 0.000366; endogamy index, 0.05, 0.43, 0.30, and 0.42; local inbreeding, 0.0003, 0.00045, 0.0009, and 0.0011; the degree of isolation by distance, 0.0003, 0.00045, 0.0009, and 0.0005; sigma, 2098, 1338, 1473, and 1189; the load of autosomal dominant (AD) diseases, 0.71, 0.92, 0.92, and 1.37; the load of autosomal recessive (AR) diseases, 0.68, 0.69, 0.67, and 0.82; and the load of X-linked diseases, 0.18, 0.64, 0.83, and 0.27.