Medico-genetic study of the population of Turkmenia. IV. The population geography of hemoglobinopathies

Large-scale screening for hereditary haemoglobinopathies in five districts and among main Turkmen tribes was carried out. The frequencies of ABO and HP pheno- and genotypes were determined in the same populations. The different kinds of haemoglobinopathies genes were discovered (beta +, beta 0-thalassemia, alpha beta-thalassemia, alpha-thalassemia, HPFH, haemoglobins D and E). The geographic and ethnic differentiation of Turkmen population for beta-thalassemia géne was discovered. The FST values were found to be the same for ABO, Hp and beta-thal gene systems. The role of genetic drift in differentiation of Turkmen population is discussed.     

Medico-genetic study of the population of Uzbekistan. IV. Medico-genetic description of the population of 4 villages of the Urgut district of the Samarkand region]

The data about the incidence of hereditary diseases and those with genetic predispositions which received after subtotal medico-genetical examination of the inhabitants of 4 villages in the Urgut district of the Samarkand province are presented. 848 inhabitants (348 adults and 464 children aged 7--16 years) are examined. The nosological profile of the morbidity and spectrum of the Mendelian diseases in the population is evaluated. The integrative estimate of load of the detrimental (non-lethal) genes is about 0.166 per individual.     

Medico-genetic study of the population of the Samarkand region. II. Population-genetic description of 4 kishlaks of the Urgut district]

This report is a second one in a series of works devoted to the medico-genetical screening of Uzbekistan populations. The paper comprises the results of the analysis of the populational structure of one of the village councils (soviets) of the Urgut District of the Samarkand Region. The main parameters of the population studied were as follows: total number 1529 persons, the average number of inhabitants of one village--328. The proportion of the inhabitants studied--56%, the average number of persons per family--5.22; the average period between subsequent generations--30-35 years, the gametic index--0.8, the inbreeding coefficient inferred from pedigrees--0.018899--0.00781, Fst = 0.03577, the average genetic distanse according to Edwards--0.0231-0.0671. The distribution of Mendelian markers (ABO, Rh, Hp and Ptc) was studied. The observed ratio between a high degree of inbreeding and a relatively low extent of isolation of populations permits to explain satisfactorily the distribution and frequencies of hereditary pathology in the Urgut District of the Samarkand Region pointed out in the previous report.     

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.     

Medico-genetic study of the population of Uzbekistan. I. Incidence and variety of hereditary pathology]

In district of the Samarkand province the screening for families burdened with multiple cases of non-infectious diseases was performed. The principles of the applied screening procedure are described in the present paper. In the course of clinical examination 98 families were detected, 55 of which included more than one person suffering presumably with Mendelian diseases and 43--with multifactorial disorders. Over 30 nosological forms were found, among which orthopaedic and neurological forms were the most frequent. As a rule, identical cases were detected in one or two families. The role of certain genetic processes in the distribution of hereditary diseases in the Uzbek population is discussed.     

Medico-genetic study of the population of Kostroma Province. VII. Approaches to the study of the hereditary pathology load in the population of Kostroma

Complex medical-genetic study was performed in the center of Kostroma Province with the population of about 250 thousands. A method for ascertainment of patients was developed and the information value of different sources of a registration system available is given. The complete algorithm of calculation of both the segregation frequency and the fraction of sporadic cases for autosomal recessive diseases is presented.     

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.     

Medico-genetic study of the Uzbekistan population. X. Hereditary forms of hearing impairment in the Khorezm and Samarkand regions

Medical-genetic study in some populations of Khorezm (about 200,000) and Samarkand (about 56,000) provinces was performed with the view of identification of all family cases of deafness and deaf-mutism. 53 families with 140 affected patients were registered, in total. 8 nozological forms were found in this study, the most frequent being autosomal-recessive ones (6 nozological forms, 48 families, 122 patients). The autosomal-dominant forms were represented by 2 nozological forms (5 families with 18 patients). The reason for predominance of autosomal-recessive deafness in Uzbek population is discussed.     

Medico-genetic study of the population of Turkmenistan. I. Hereditary diseases in 5 districts of the Ashkabad region

Medico-genetic characteristics of the Ashkhabad province of Turkemenia are given. 23 nosological forms of hereditary diseases were found. The population load estimated per 1000 of autosomal-recessive (AR) diseases was 0.7, autosomal-dominant (AD) - 0.4, X-linked - 0.5. Inbreeding coefficient for the families with AR pathology was 0.03529, with AD - 0.01172. The study of territorial distribution of hereditary disease detected slightly marked local accumulation of certain forms of hereditary diseases.     

Medico-genetic study of myopathies in a population of Pamir and Karategin valley of the Tadzhik SSR

The clinic-genealogical and population-genetical studies were undertaken to reveal the myopathia patients. The frequency of myopathies in a population of Tajiks, their clinical polymorphism and the course of the pathologic process, depending on factors of environment were studied. In the population of Pamir people, who were exposed to external conditions, 25 patients with the neural amyotrophy, 8 patients with shoulder, shoulder-blade and face form of progressive muscle distrophy, 4 patients with Erba's PMD and 3 with the pseudohypertrophic Dushen form were revealed. High frequency of the neural amyotrophy was connected with the marriage election of the population, its isolation and accumulation of heterozygote carriers. Earlier onset of progressive muscle distrophy was connected with sharp change in climate and great physical burdens which led to the disarrangement of the adaptation system. It was established that 17 patients with the shoulder-blade and face form of the PMD, 5 patients with the sporadic form of the neural amyotrophy, 3 patients with the Dushen's PMD, 2 patients with the Erba's PMD and 1 patient with the spinal amyotrophy inhabited Karategin valley having the continental climate. The high level of migration of these populations resulted in dissemination of the gene in the valley regions. The quantity of abortions and still-borns in families suffering from myopathy is fewer than in Pamir.     

Medical genetic study of the population of Turkmenia. VI. An analysis of the genetic component of fertility dispersion in the population of Nokhor

The index of the total opportunity for selection (the Crow index) and the genetic part of total variance in progeny size was studied in small Turkmenian isolated population Nochur. The average number of children per family in families that had completed their reproductive period was 6.84, the variance being 12.31. The index of total opportunity for selection was computed by the standard method of J. Crow: Jm = 0.313, Jf = 0.454, Jtot = 0.909. Some correlation coefficients of the progeny size were calculated. The sister-sister correlation coefficient was significantly distinguished from 0 and was equal to +0.22. Thus, the genetic part of total variance of the progeny size is 0.4-0.5. It is essential for understanding of the Jf estimation.     

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.     

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.     

Medico-genetic study of the population of Uzbekistan. III. Phenotypical assortativity as a factor in population structure (using palmoplantar hyperkeratosis and vitiligo as examples)]

The article comprises the examples of homophenogamic marriages between persons with a rare hereditary dominant character, hand-palm and foot-sole hyperkeratosis, leading to the increase of inbreeding intensity in the population. On the contrary, homophenogamic marriages between persons with vitiligo, a considerably more widespread character, lead to the decrease of the degree of inbreeding in a population, since they take place between partners coming from different districts of the region.     

Medico-genetic study of the population of Uzbekistan. VI. Hereditary pathology among the populations of 4 regions of the Kashkadarinskaia area]

The screening for families burdened with multiple cases of non-infectious diseases, the diagnostic of those diseases and the investigation of relations between the population structure and the distribution of hereditary diseases in 4 districts of the Kashkadarja province were carried out. On the basis of the data obtained the load of excessive hereditary diseases was calculated and nosological spectrum was described; it included more than 30 different diseases. The study of spatial distribution of recessive diseases has shown that the load of hereditary diseases may be accounted for the positive assortative matings. The high level of interpopulation migration prevents from the local accumulation of a certain hereditary disease.     

Medico-genetic study of the residents of Krasnodar territory. Incidence of hemoglobinopathies

Data on distribution of various types of hemoglobinopathies in the Krasnodar region are presented. This region was unfavourable, due to malaria in the past. The results obtained allow to conclude that the territory needs more attention as a possible focus of beta-thalassemia in our country.     

Medico-genetic study of the Kostroma Region population. VIII. Genetic structure of large subdivided populations and its relation with the incidence of autosomal-recessive pathology

FST was estimated for 67 communities and 6 small towns of Kostroma province. The mean FST value for rural and urban populations was (0.83 +/- 0.08).10(-3) and (0.29 +/- 0.07).10(-3), respectively. The connection between FST values and the load of autosomal-recessive disorders was established; the coefficient of correlation (by Chuprov) was 0.34 (chi 2 = 8.45; P less than 0.05). The matrices of genetic distances for two groups of districts of Kostroma province, based on surnames frequencies, were calculated. Dendrogramms were constructed using genetic distances, which reflect the degree of genetical similarity of the populations. The conclusion drawn from the analysis of these dendrogramms is that there is distinct isolation by distance in populations of Kostroma province. It is shown that genetical subdivision of populations is dependent on geographical and some other factors and on the load of autosomal-recessive pathology in the population.     

Medical genetic study of the population of Turkmenia. VI. Intrapopulation variability from an analysis of marriage migrations and ABO and Hp marker systems

By the sampling procedure, the distribution of phenotypic and genotypic frequencies of ABO and Hp systems and the structure of intermarriage migration in Turkmen population was studied. The geographical subdivision of the Turkmen population coincided with its ethnic divergency. The main Turkmen tribes are highly isolated (the gametic index is 0.965 to 1.0) and the differences in gene frequencies between tribes are significant. The mean gene frequencies for the ABO system in the Turkmen population are: I0-0.5373, IA-0.2601, IB-0.2025, these being Hp1-0.284, Hp2-0.716 for the Hp system.