Medico-genetic studies of the Kostroma oblast population. X. Load of hereditary diseases in the population of Kostroma

Medical-genetic study of the population of Kostroma (the total size of the population analysed approx. 250,000) was carried on. The load of hereditary diseases in the population (per 1000) was 0.75 for autosomal dominant, 0.49 for autosomal recessive and 0.17 for X-linked recessive disorders. Significant differences in the prevalence of autosomal recessive hereditary disorders between rural populations and the population of Kostroma were observed. The dependence of the load of autosomal recessive pathology on random inbreeding was shown for the whole Kostroma province.     

Genetic load of hereditary diseases in populations of the Krasnodar Krai]

Medico-genetical study of populations living in Krasnodar district was carried out. The mean value of genetic load contributed by autosomal dominant diseases composed 0.92 +/- 0.06, this value being 0.56 +/- 0.04 for autosomal recessive and 0.36 +/- 0.05 for X-linked recessive disorders per one thousand. Comparative analysis of genetical load in urban and rural populations demonstrated that they had no differences in relation to genetical load contributed by autosomal recessive and X-linked recessive disorders. At the same time, significant differences were noted between the populations concerning genetic load contributed by autosomal-dominant disorders.     

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.     

Spectrum and territorial distribution of hereditary diseases in the population of the Krasnodar Krai]

The analysis of the spectrum of hereditary diseases in the population of the Krasnodar province is performed and the influence of the population dynamics factors on the spectrum is discussed. More than 130 nosological forms were discovered in the population of approx. 200,000. Among these, there are 63 autosomal dominant, 49 autosomal recessive and 17 X-linked recessive forms. Of the most frequent autosomal dominant diseases (more than 1 per 50,000) autosomal recessive and X-linked recessive disorders 13, 7 and 7 forms, respectively, were picked up. The coefficient of diversity of hereditary diseases (the number of nosological forms per 10 inhabitants) with different types of inheritance is higher in the Krasnodar population, as compared with the Kostroma population. The problem of similarity of the "nucleus" of autosomal-recessive disorders in Russian populations is discussed.     

Hereditary diseases of nervous system in the population of Vladimir province

The first population genetic study of hereditary disorders of the nervous system (HDNS) in Vladimir oblast was carried out. A total of 1,622,900 subjects, including 1,306,200 from the urban and 316,700 from the rural population, were tested. The population examined was characterized by virtually homogenous ethnic structure, with Russians constituting 95.76%. Pooled prevalence of HDNS in Vladimir oblast corresponded to the average prevalence for other Russian populations. Substantial differences between urban and rural populations in respect of the population load of HDNS and its nosological structure were not observed. A total of 22 nosological forms of HDNS were revealed, including thirteen autosomal dominant (193 families with 272 affected individuals), seven autosomal recessive (59 families with 66 affected individuals), and two X-linked (15 families with 17 affected individuals) diseases. The composition of the HDNS spectrum "nucleus" in Vladimir oblast displayed a number of differences from that in the majority of other populations examined. The HDNS in different regions of the area tested were characterized by different prevalence and spectrum. The data obtained may constitute a basis for regional registration of HDNS in Vladimir oblast.     

Burden of hereditary diseases in residents of the Sakh republic (Iakutiia)

Summarized data of medical genetic survey of the population of Republic of Sakha (Yakutia) are presented. The number of the population examined constituted 1000700 individuals (including 424500000 of urban and 576,200 of rural population, respectively). Regarding the ethnicity, 33 regions of the Republic examined were at most inhabited by Yakuts (36%) and Russians (55%). A total of 400 families (606 patients) with autosomal dominant, 274 families (369 patients) with autosomal recessive, and 42 families (53 patients) with X-linked pathologies were detected. The segregation analysis performed showed good correlation with the expected type of inheritance for both dominant and recessive diseases. The prevalence rate of monogenic hereditary diseases for rural and urban populations, as well as for solely Yakuts, was calculated. It was shown that weighted average prevalence of dominant (0.68; 1.44) and recessive (0.43; 0.86) disorders in Yakuts was two times higher than in total population examined.     

Burden of hereditary diseases in residents of the Mari El Republic]

A summary of the medical genetic studies of the Marii El population is presented. A total of 276,900 people, 110,894 and 166,006 urban and rural inhabitants, respectively, were examined. Regarding the ethnic composition, the studied population was mostly Mari (61.96%) and Russian (32.04%). Medical genetic examination revealed 480 subjects from 260 families with autosomal dominant (AD) diseases, 234 subjects from 184 families with autosomal recessive (AR) diseases, and 49 subjects from 41 families with x-linked diseases. Segregation analysis revealed a good agreement between the expected and observed segregation frequencies for families with AR and AD diseases and allowed the frequency of hereditary diseases in the urban and rural, as well as the Russian and Mari, populations, to be estimated. The total frequency of AD diseases in Maris was approximately twice as high as in Russians (1.99 and 0.97%, respectively); substantial differences between district populations were found. The total frequency of AR diseases was also two times higher in Maris than in Russians (1.00 and 0.54%, respectively). The frequencies of AR and AD diseases in different districts were correlated with the levels of random and local inbreeding, population size, and the index of maximum selection.     

The Load of Hereditary Diseases in the Population of Republic of Sakha (Yakutia)

Summarized data of medical genetic survey of the population of Republic of Sakha (Yakutia) are presented. The number of the population examined constituted 1 000 700 individuals (including 424 500 of urban and 576 200 of rural population, respectively). Regarding the ethnicity, 33 regions of the Republic examined were at most inhabited by Yakuts (36%) and Russians (55%). A total of 400 families (606 patients) with autosomal dominant, 274 families (369 patients) with autosomal recessive, and 42 families (53 patients) with X-linked pathologies were detected. The segregation analysis performed showed good correlation with the expected type of inheritance for both dominant and recessive diseases. The prevalence rate of monogenic hereditary diseases for rural and urban populations, as well as for solely Yakuts, was calculated. It was shown that weighted average prevalence of dominant (0.68; 1.44) and recessive (0.43; 0.86) disorders in Yakuts was two times higher than in total population examined.     

Medico-genetic study of the population of Uzbekistan. VIII. Territorial distribution of hereditary diseases in the population of four regions of the Khorezm province and its genetic load

The load of hereditary diseases was estimated on the basis of data obtained during medical-genetic study of the population of four districts of Khorezm province. The load of autosomal recessive disorders comprised 2-3 X 10(-3) affected, that of autosomal dominant disorders - 0.4-0.5 X 10(-3) and that of X-linked disorders - 0.2-0.4 X 10(-3) males. The main part of patients with autosomal recessive disorders belonged to separate families randomly spread over the populations. A trend for local accumulation of families with the same disorder was observed in small populations. It was shown that overall frequency of autosomal recessive genes per individual increased with the increase in the population size.     

Hereditary Diseases of Nervous System in the Population of Vladimir Oblast

The first population genetic study of hereditary disorders of the nervous system (HDNS) in Vladimir oblast was carried out. A total of 1622900 subjects, including 1306200 from the urban and 316700 from the rural population, were tested. The population examined was characterized by virtually homogenous ethnic structure, with Russians constituting 95.76%. Pooled prevalence of HDNS in Vladimir oblast corresponded to the average prevalence for other Russian populations. Substantial differences between urban and rural populations in respect of the population load of HDNS and its nosological structure were not observed. A total of 22 nosological forms of HDNS were revealed, including thirteen autosomal dominant (193 families with 272 affected individuals), seven autosomal recessive (59 families with 66 affected individuals), and two X-linked (15 families with 17 affected individuals) diseases. The composition of the HDNS spectrum nucleus in Vladimir oblast displayed a number of differences from that in the majority of other populations examined. The HDNS in different regions of the area tested were characterized by different prevalence and spectrum. The data obtained may constitute a basis for regional registration of HDNS in Vladimir oblast.     

Genetic epidemiological study of populations in three regions of Chuvashia Republic

Comprehensive population genetic and medical genetic studies were performed in three raions (districts) of Chuvashia. The population of these districts is more than 90% Chuvash. About 70% of the families that completed reproduction had two or three children. The proportion of families with four or more children was 18%. The duration of generation was 27.6 years. The differential fertility and differential mortality indices in the Chuvash population were estimated at 0.33 and 0.076, respectively. The total index of differential selection was 0.403, which is typical of modern urbanized populations. Mean values of local inbreeding calculated from Malecot's model of isolation by distance were 0.00124 and 0.00377 for the urban and rural populations, respectively, of the districts studied. The prevalence rates of autosomal dominant (AD), autosomal recessive (AR), and X-linked diseases were found to be 0.47, 0.52, and 0.35 per 1000, respectively, in the urban population and 1.62, 1.14, and 0.31 per 1000, respectively, in the rural population. Significant correlation between the local inbreeding and prevalence rates of AD and AR diseases was found. A total of 43 AD and 43 AR diseases were identified. Some of them were not found in previous studies on other populations.     

Genetic Epidemiological Study of Three District Populations in Chuvashia

Comprehensive population genetic and medical genetic studies were performed in three raions (districts) of Chuvashia. The population of these districts is more than 90% Chuvash. About 70% of the families that completed reproduction had two or three children. The proportion of families with four or more children was 18%. The duration of generation was 27.6 years. The differential fertility and differential mortality indices in the Chuvash population were estimated at 0.33 and 0.076, respectively. The total index of differential selection was 0.403, which is typical of modern urbanized populations. Mean values of local inbreeding calculated from Malecot's model of isolation by distance were 0.00124 and 0.00377 for the urban and rural populations, respectively, of the districts studied. The prevalence rates of autosomal dominant (AD), autosomal recessive (AR), and X-linked diseases were found to be 0.47, 0.52, and 0.35 per 1000, respectively, in the urban population and 1.62, 1.14, and 0.31 per 1000, respectively, in the rural population. Significant correlation between the local inbreeding and prevalence rates of AD and AR diseases was found. A total of 43 AD and 43 AR diseases were identified. Some of them were not found in previous studies on other populations.     

Medico-genetic study of the population of Kostroma Province. I. The population burden of hereditary pathology

Data on the prevalence of hereditary diseases in five regions of the Kostroma province were obtained and analysed. It was shown that the ascertainment was close to the truncate selection for the rural population and to the single selection for the urban population. Segregational analysis proved the rightness of the material subdivision, according to the type of inheritance. The load of hereditary diseases (for the registered forms) in the population was: 0.78 +/- 0.08 X 10(-3) for autosomal dominant, 0.75 +/- 0.08 X 10(-3) for autosomal-recessive and 0.54 +/- 0.1 X 10(-3) for X-linked recessive disorders. The dynamics of the load of hereditary diseases in the populations with different structure is discussed.     

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 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.     

Genetic and Epidemiologic Analysis of Hereditary Diseases of the Nervous System in the Cities of Volgograd and Volzhsky

A genetic epidemiological study of hereditary diseases of the nervous system (HDNS) was conducted in the cities of Volgograd and Volzhsky for the first time. In total, 1 323 500 individuals were examined including the populations of Volgograd and Volzhsky (1 012 800 and 310 700 persons, respectively). The prevalence of neurological diseases with autosomal dominant (AD), autosomal recessive (AR), and X-linked recessive inheritance was estimated. These data were compared with the estimates previously obtained for different population of the Russian Federation. A decrease was found in general HDNS load in Volgograd and Volzhsky. The compared populations were shown to differ in a contribution of AD, AR, and X-linked recessive diseases into the HDNS load formation. The possible effect of population dynamics factors on the HDNS load structure is discussed.     

Medico-genetical study of the population of the Kostroma Region. IV. Genetic load and diversity of hereditary pathology in 5 districts

Data on the prevalence of hereditary diseases in five regions of the Kostroma province were obtained and analysed. 28 autosomal recessive, 25 autosomal dominant and 4 X-linked recessive disorders were found. Segregation analysis proved the rightness of the material subdivision, according to the type of inheritance. The load of hereditary diseases in five regions was: 0.86 +/- 0.09 X 10(3) for autosomal recessive, 0.97 +/- 0.1 X 10(3) for autosomal dominant and 0.36 +/- 0.09 X 10(3) for X-linked recessive disorders. The problems of prevalence of hereditary diseases connected with population structure is discussed.     

Medico-genetic study of the population of Uzbekistan. VII. Variability of hereditary pathology in 4 regions of Khorezm province

Medical-genetic study was carried out in the population of Khorezm province (population size above 200 000 persons). Hereditary pathology was ascertained among families having two or more members affected with chronic non-infectious diseases. 155 families with 348 members affected with hereditary diseases were registered. The most frequent were autosomal recessive diseases (55 nosological forms in 104 families with 271 affected), then followed the autosomal dominant conditions (10 nosological forms in 21 families with 53 affected). The less frequent was X-linked recessive pathology (6 forms in 12 families with 20 affected). The main part of cases of autosomal recessive pathology were found in separate families and were not observed during previous medical-genetic studies in Uzbekistan. Three autosomal recessive conditions are probably new forms of hereditary pathology. The important role of assortative matings in manifestation of rare autosomal recessive genes in Uzbek population is discussed.     

Medical genetic study of the population of Turkmenia. III. Hereditary pathology in Turkmen Nokhurlis

Medical-genetic investigations were carried out in isolated population of Nokhurlis inhabiting some villages of Ashkhabad and Krasnovodsk provinces. A high coefficient of inbreeding, high endogamy, and low coefficients of migration were found for this population. Two hereditary disorders are relatively frequent among the Nokhurlis and lacking in neighboring populations. The frequency of the autosomal dominant gene for congenital cataract is 0.26% and that of the autosomal recessive gene for a peculiar form of obesity is 2.47%. In both cases, the main factor affecting gene accumulation appears to be the result of genetical drift effect. The total load of hereditary diseases of higher in Nokhurlis than in other Turkmen populations. The connection between the population structure of Nokhurlis and the accumulation of hereditary disorders is discussed.     

Genetic and epidemiologic analysis of hereditary diseases of the nervous system in the cities of Volgograd and Volzhskiĭ

A genetic epidemiological study of hereditary diseases of the nervous system (HDNS) was conducted in the cities of Volgograd and Volzhsky for the first time. In total, 1 323 500 individuals were examined including the populations of Volgograd and Volzhsky (1 012 800 and 310 700 persons, respectively). The prevalence of neurological diseases with autosomal dominant (AD), autosomal recessive (AR), and X-linked recessive inheritance was estimated. These data were compared with the estimates previously obtained for different population of the Russian Federation. A decrease was found in general HDNS load in Volgograd and Volzhsky. The compared populations were shown to differ in a contribution of AD, AR, and X-linked recessive diseases into the HDNS load formation. The possible effect of population dynamics factors on the HDNS load structure is discussed.