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 residents of the Kostroma province. XI. Diversity of hereditary pathology in Kostroma

The diversity of hereditary pathology in Kostroma was studied. An attempt was made to classify all isolated cases by genetic and clinical analysis. 57 nosological forms of autosomal dominants, 41 autosomal recessive and 14 X-linked recessive disorders were found. The analysis of marriage distances in the whole population and in the families of the probands was carried out. The spectra of hereditary pathology in Kostroma and Kostroma Province were compared. The sources of the load of hereditary pathology in Kostroma are discussed.     

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. 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.     

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 Kostroma Province. VI. The parameters of isolation by distance in the populations of the Bui and Shar'ya Districts of Kostroma Province

A model of isolation by distance proposed by Malécot and developed by Morton is applied to the data on marriage distances collected in two regions of Kostroma Province. There is good agreement between the estimates of local inbreeding when using the isonymy method and the model of isolation by distance. Interpopulation kinship approaches 0 at the distance 700 km. The mean coefficient of kinship for parents in the families with autosomal-recessive pathology is 20 times higher than mean coefficient of kinship in the population.     

Medical genetic study of the population of Kostroma Province. V. The hereditary pathology burden of urban and rural populations

Medical genetic study was carried out in the urban and rural populations of Kostroma Province. Urban populations were shown to have lower frequencies of "rare" forms of autosomal recessive diseases, in comparison with those in the rural populations. Analysis of interrelationship between genetical structure of populations and prevalencies of hereditary diseases in the populations revealed clear relations between the load of autosomal recessive diseases and the level of inbreeding in the populations.     

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.     

Medical genetics study of the population of Kostroma Province. II. The diversity of hereditary pathology in 5 districts of the province

The diversity of hereditary pathology in 5 regions of Kostroma district was studied. 32 nosological forms of autosomal dominant, 30 autosomal recessive and 7 X-linked recessive disorders were found. The most frequent autosomal dominant disorders were: neurofibromatosis, pigmentary degeneration of retina, hypochondroplasia, ichtiosis, idiopathic scoliosis. The most frequent among the autosomal recessive disorders were: oligophrenia, pigmentary degeneration of retina, muscular atrophy of juvenile Kugelberg--Welander type, congenital cataract. The most frequent X-linked disorders were: muscular Duchenne type dystrophy and hemophilia A. Analysis of mutant gene distribution over the territory by the study of birthplaces of probands and their parents was carried out.     

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.     

Medico-genetic study of the population of the Kostroma region. III. Inbreeding coefficient and its dynamics in rural populations and small towns

Analysis of the inbreeding coefficient, its structure and dynamics in rural and urbanized populations of the Kostroma province was performed. The coefficient of inbreeding was estimated for the "old" and "new" villages via migration and isonymy, the values being 0.001185; 0.000786 and 0.001341; 0.000682, respectively. It follows from these data that there is a good agreement between the values of the inbreeding coefficient estimated by two different methods and that this coefficient is diminished doubly in "new" villages. The coefficient of inbreeding in small towns was estimated via isonymy. It is 0.000704 in ancient and 0,000229 in modern towns. The decrease in the inbreeding coefficient was more pronounced in towns, as compared to villages.     

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-genetical study of the Uzbekistan population. IX. Variability of hereditary pathology, territorial distribution of hereditary diseases and hereditary disease load in the population of the Urgut district of the Samarkand region

Medical-genetic study was carried out in the population of Samarkand province (the population size about 150 000). Hereditary pathology was ascertained among families with two or more affected members with chronic diseases. 110 families with 210 patients were registered. The most frequent were autosomal-recessive disorders (42 nozological forms). 15 nozological forms are probably "new" conditions in this province, because they were absent in our previous medical-genetic study of this province. A tendency to local accumulation of families with the same disorder in small populations was observed. The load of autosomal-recessive disorders comprised 2.2 X 10(-3) affected, that of autosomal-dominant disorders being 0.51 X 10(-3) and of X-linked disorders being 0.25 X 10(-3) males. The importance of assortative maitings in manifestation of rare autosomal-recessive genes in Uzbek population is discussed.     

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 isolates in Uzbekistan. IV. Clinico-biochemical diagnosis of hereditary diseases]

An exhaustive clinico-biochemical examination of the population of two kishlaks of the Samarkand Region, viz. Karakent (210 persons) and Ishan (248 persons) was carried out. The program of this examination permitted to exclude over 160 forms of hereditary pathology. A total of 45 persons affected with diseases belonging to 12 nosological forms were revealed in the course of the examination. Among the diseases observed only 5 are hereditary sensu stricto, viz. myoclonus-epilepsy, Bonevi-Ulrich's syndrome, imperfect osteogenesis, pigment choreoretinite and Down's syndrome, others belong to diseases with a pronounced hereditary predisposition. The main part of this group comprises neuro-psychic diseases, such as non-differentiated olygophreny (5.0%), epilepsy (1.3%), schizophreny; many of these cases have a familial character, particularly in Karakent. Besides the persons suffering from diseases, 20 heterozygous carriers of beta-thalassemia and 17 heterozygous carriers of G6PD-deficiency were discovered in the kishlaks examined. On the whole the frequency of the diseases revealed did not exceed the level in the general population. Despite the different degree of isolation of the kishlaks examined (Karakent is isolated on a religious basis, F = 0.0064; while Ishan is a desintagrated isolate, F = = 0.0014), no substantial differences between them in the distribution of pathological phenomena were observed. On the basis of the experience of this expedition recomendations are proposed concerning the origination and accomplishment of medico-genetic expeditions. A scheme is proposed for the performance of medico-genetic examination through several stages. The first stage in the composition of tentative maps of the distribution of hereditary diseases within a region on the basis of the information obtained from the medical personnel and from the examination of the documents of district and regional hospitals. Subsequently the primary information is specified, the regions to be examined are determined, as well as concrete tasks and the staff of the expedition. The conclusive stage is the medico-genetic examination proper, including clinical, biochemical, immunological and cytogenetic diagnoses of hereditary pathological phenomena. The place of the disposition is a village or a district hospital. More complicated laboratory studies should be performed on the basis of the institution by which the expedition is formed. The results obtained by such expeditions would be important for the investigation of the problems of genogeography, for the discovery of new forms of mutant alleles, for the investigation of the causes and the conditions of the formation of the definite populational structure, of clinical polymorphism of human hereditary diseases.     

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 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.     

Medical genetic study of the population of Turkmenia. II. Study of the distribution of hereditary pathology in 5 regions of Tashauz Province

The large-scale screening for hereditary diseases in five regions of the Tashauz province was carried out. More than 50 families represented by persons with different nosological forms of hereditary diseases, were found. The role of drift in rare mutant gene dynamics was shown. The load of hereditary diseases was mainly connected with autosomal recessive forms and shown to vary between the regions from 0,34 to 1,29 pro mille.     

Medico-genetic study of the population of Turkmenia. V. A population and demographic description of the Nokhur isolate

The paper deals with demographic, genealogical and genetic characterization of one Turkmenian isolate--"Nochur". The data on its load of hereditary diseases were published previously. The Turkmenian "Nochurly" tribe consists of 19 large and small clanes. 600 nuclear families live in a small mountain valley of the same name. The share of prereproductive age class is 60%, of reproductive class--29%, this value for postreproductive class being 11%. The average number of children per family, when the families have completed their reproductive period, is 6.84. The average duration of generation (the mean parental age to the birth time of a mean newborn) is 37.7 and 31 years for a man and woman, respectively. Immigration into Nochur is practically absent, there is a flow of emigrants to the capital of the Republic, Ashkhabad. A very high level of assortative mating has been noted, the minimal estimation of inbreeding coefficient being 0.033 (the pedigree) and the maximal--0.0529 (isonimy). Diminishing of the number of lethal equivalents between 1940-1965 and 1966-1980 was discovered. This can be explained by a decrease in natural selection pressure. The data on distribution of genetic markers of the ABO, MN, Rh, Hp and Pp systems within this isolated population are presented.     

Genomic study of the hereditary pathology and genetic diversity of the Siberian population

The review considers the results of genome research on the Russian program Human Genome carried out in the Institute of Medical Genetics (Tomsk) from 1990. The three major fields were molecular cytogenetics and chromosomal disorders, genomics of Mendelian and high-incidence diseases, and ethnogenomics of the North Asian population. Several human genes were cytogenetically mapped, and numerical and structural abnormalities associated with human diseases studied by fluorescence hybridization. Procedures of DNA diagnostics were developed for 15 hereditary diseases. New data were obtained on genetic heterogeneity of idiopathic hypertrophic cardiomyopathy. The genetic bases of multifactorial (atopic bronchial asthma) and infectious (tuberculosis) diseases were analyzed. The North Eurasian population (41 local populations of 21 ethnic groups) was tested for genetic diversity with numerous genetic markers, including Y-chromosomal haplotypes, autosomal microsatellites, and polymorphic Alu insertions.