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A S Sergeev

Publications and source records attributed to A S Sergeev.

At least 19 recordsLinked to original sources
PubMed1996

[Computer programs SAN and EPID: family analysis and epidemiology of multifactorial diseases].

SAN software, a database management system, is elaborated. It is subject-oriented to family analysis in the genetics of multifactorial traits (diseases). The software allows creating and maintaining a family-oriented database and using the inputted information to calculate relative risk of disease, heritability, and correlations between several diseases or forms, with both actual frequency of the trait (prevalence) and probability of new cases (incidence). If appropriate data on sibships or nuclear families are available, one can calculate an empirical estimation of the risk of repeated cases of the disease in a family in relation to family anamnesis in different methods of sampling, sex-related morbidity, and varying age of onset. The database may also be used independently as a card index. The software allows one to represent pedigrees graphically, highlighting the desired set of traits. As application program, EPID, was developed, aimed at calculation and graphical presentation of age-related estimations of prevalence and incidence, as well as of the population risk of an individual to develop a disease within a time interval from birth to a certain age (accumulated morbidity).

Causality↗
PubMed1996

[Retrospective estimation of the frequency of heterozygous beta-thalassemia in the Crimean Tartar population. Formulation of the problem. Estimation of the gametic contribution to a mixed population from frequencies of the ABO blood group genes].

Polymorphism of the beta-thalassemia gene frequency in non-indigenous populations of Central Asia, especially Crimean Tartars, is often explained by inter-ethnic marriages. The frequencies of these marriages, however, are not sufficient to produce the observed gene frequencies. Because of this, an estimation of the extent of Uzbek gametic contribution to the ethnic group of Crimean Tartar origin was conducted using data on the frequencies of ABO blood group genes. The maximum-likelihood estimate obtained (0.325) was used to determine the heterozygous beta-thalassemia frequency of the ancestral Crimean Tartar population.

ABO Blood-Group System↗
PubMed1996

[Retrospective estimation of the frequency of heterozygous beta-thalassemia in the Crimean Tatar population. Estimation of gene frequency in the ancestral population based on mixed population data with a known admixture rate].

Results of the maximum-likelihood estimation of heterozygous beta-thalassemia frequency in the Crimean Tartar ancestral population obtained by evaluating the gametic contribution of Uzbeks to the Crimean Tartar ethnic group are presented. The computing algorithm is given, and reliability of the obtained results is discussed.

Algorithms↗
PubMed1995

[Population risk of bronchial asthma occurrence in Moscow].

Age-specific prevalence and incidence of bronchial asthma (BA) were estimated in a number of districts in Moscow. The average prevalence was measured as the current proportion of BA patients registered in district outpatient clinics of both the center and periphery of Moscow (2442 patients in total) among the entire population served by to these clinics. This proportion was found to be 0.5% for both men and women. Before 25 years of age, BA appeared to be commoner in males (0.57%, versus 0.3% in females); after 40 years of age, it was commoner in females (0.89%, versus 0.47% in males). The morbidity of the disease measured as the frequency of new cases of BA (diagnosed for the first time in the given patient) had two maximums for each gender: in females, between birth and nine years of age and at 45-54 years (0.39 and 0.45%, respectively) and in males, between birth and nine years and at 55-64 years (0.75 and 0.74%, respectively); and a minimum at 20-29 years of age (0.14 and 0.05% for females and males, respectively). The majority (80%) of adult BA patients were first diagnosed with BA in adulthood. The dynamics of BA incidence appeared to differ in males and females. The male incidence changed more drastically with age, while the incidence in adult females reached a maximum 10 years earlier than in adult males. The population risk of being registered for BA (accumulated morbidity) by the age of 15, 40, and 80 was 0.98, 1.35, and 2.97%, respectively, for males and 0.58, 0.95, and 2.13%, respectively, for females.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1994

Frequency analysis of HLA-DQA1 and HLA-DQB1 gene alleles and susceptibility to type 1 diabetes mellitus in Russian patients.

The HLA-DQA1 and DQB1 genes have recently been recognized to be strong genetic markers of susceptibility to type 1 (insulin-dependent) diabetes mellitus. The Arg52 DQA1 and non-Asp57 DQB1 alleles of these genes correlate with the disease predisposition and the Asp57 DQB1 and non-Arg52 DQA1 alleles with disease protection. We investigated 113 patients with type 1 diabetes and 121 healthy subjects from the Russian population of Moscow using DNA amplification and dot-blot hybridization with sequence-specific oligonucleotides (SSO). Using conventional statistical methods we confirmed previous observations indicating the important role of the above-mentioned amino acid residues in susceptibility and resistance to type 1 diabetes. Relative risk values for all alleles and absolute risk for carriers of most predisposing allele combinations were calculated. The absolute risk for carriers of DQA1 and DQB1 gene alleles allowing for the formation of four possible 'diabetogenic' heterodimers on the surface of immunocompetent cells, regardless of the type of coding (cis or trans), was 2.54%, which is 13 times greater than the background risk for the Russian population--0.2% up to 30 years of age.

Adolescent↗
PubMed1993

[Empirical estimation of recurrence risk in diseases with variable age-at-onset: correction].

Combinatorial approach in empirical estimation of recurrence risks in variable age-at-onset (AO) was elaborated in [2], where special combinatorial coefficient was introduced, the so called "constrained polynomial coefficient", which permit to count the permutations of AO-sibling classes, constrained by their age to the time of study (ATS). Unfortunately giving account of method of calculation md--the table morbidity rate--for siblings of age d in [2] were not introduced limitations for AO or ATS of those siblings, which were affected before or not yet reached the age d under evaluation. Lack of the limitations result in the estimate of prevalence (i.e. the proportion of affected siblings, with the given AO, among all the siblings), but not incidence or age-specific morbidity rate (i.e. the proportion of the siblings, affected in the d-th age interval among those siblings, who reached and/or outlive the age d, being free of disease before the age d under evaluation). In this communication the oversight is removed and the method of calculation of md is simplified: only the two classes instead of a lot of the possible AO-classes of siblings are considered, namely--"affected in the d-th age interval" and "health in the d-th age interval" under evaluation. Thus, the way of calculation of md may be reduced to the simple binomial case.

Age of Onset↗
PubMed1991

[Empirical, free of genetic model, estimation of recurrence risks in multifactorial diseases: conditional probability approach].

Conditional probability approach in estimation of recurrence risks in sibships of different parental phenotypic matings with the different set of affected and normal siblings is considered. The formulae are presented for calculation of recurrence risks in cases of equal and different susceptibility of two sexes under different ways of sampling of family data: direct selection of offsprings through the parents; indirect selection of offsprings through affected siblings--the probands, under different ascertainment probability--from pi = 1.0 ("exhaustive selection") up to pi----0 ("single selection"); for the case of different susceptibility of the two sexes a possibility of the differences in the ascertainment probabilities of men (pi m) and of women (pi w) is allowed, unlike "independent ascertainment model", which requires the constancy of pi. The case of multiple incompatible subforms is considered for estimation of the recurrence risks of the specified subforms. The methods of the risks estimation proposed are free of genetic models being universal both for classical mendelian traits (with the constant risks) and for multifactorial ones (with variable risks).

Causality↗
PubMed1991

[Empirical estimation of recurrence risks in multifactorial diseases with variable age-at-onset: conditional probability approach].

Conditional probability approach in estimation of recurrence risks considered in the report is naturally extended to the case of diseases with variable age-at-onset which are divided into many age-at-onset incompatible classes, the distribution of families for classes of affected and normal siblings being polynomial, modified with regard both for classes by age manifestation and for age of relatives at the moment of observation. This case is realised within the framework of the so called "life-table" approach of general use in demography. It is emphasized that the estimate of "accumulated morbidity" obtained within this framework--as a resulting estimate of "forthcoming risk" for individuals which are at premanifestational age--is the "a posteriori" probability for relatives to be affected by the disease. It is indicated that conditional probability approach, being free of any biological models of the disease origin, is not free of ascertainment models: different kinds of stratifications of the patients for the features related to their ascertainment as probands (age-at-onset, age by the time of observation, sex, birth order, etc.) can naturally generate inconsistency of the ascertainment probability pi both within and among the families, violating the independence of the ascertainment of patients as probands. In this connection, the maximum likelihood equations are given for estimation of the ascertainment probabilities of different incompatible groups of patients as probands and the necessity to account for possible differences in pi-s is pointed out.

Age Factors↗
PubMed1991

[The affected sib-set method: revision based on the mixed model using a conditional probability approach].

One of the implicit assumptions of the single locus model, having been used so far in the analysis of linkage between the genetic marker locus and the disease predisposition locus, is the requirement of independent--from the rest of genotype--action of genotypes of the disease predisposition locus considered. In this communication, it is emphasized that the lack of this requirement makes problematical the theoretical substantiation of the affected sib-pair method in the linkage analysis. To remove this obstacle, explicit pointing out of independence of the action of the single locus genotypes on the rest of the genotype is necessary in formulating of the single locus model which, with due regard for this assumption, represents a special, perhaps, unique case of the gene action characterized by incomplete differential penetrances of the genotypes under conditions, when the genes of the rest of genotype involved to the disease, are fixed. In this connection, the mixed model of inheritance with the "major gene", proposed by Morton and MacLean (1974), is considered, on the basis of which the theoretical expectations of the proportions of the affected sib pairs, sharing the x = 2, 1, 0 haplotypes, identical by descent (IBD) in phenotypic matings with the h = 2, 1, 0 affected parents are derived. Based on the combinatorial analysis of IBD relationships in sib pairs and of the distribution of sibships of any size s greater than or equal to 2 by the numbers L = 2, 3, 4 haplotypes, inherited by s siblings, the empirical assessment of data on sibships of any size with r greater than or equal to 2 affected siblings is considered, which makes it possible to reduce the data observed on distribution of the numbers L in sibships, to that of the IBD relationships in the affected sib pairs. It is also pointed out that conditional probability approach, proposed by the author earlier, allows at the same time to obtain the empirical estimates of the recurrence risks, conditional both on phenotypes of siblings (r affected; s-r normal siblings), and on the number of L haplotypes inherited by sibships.

Chromosome Mapping↗
PubMed1990

[Genetic analysis of the structure of predisposition to diabetes mellitus. IV. Population-genetics study of two types of diabetes mellitus with onset at age 20-40].

It was found that age-specific morbidity risks of type I diabetes mellitus (DM I) increased from the age of 0-4 yrs (0.012-0.013%) to the age of 10-14 yrs (0.04-0.045%) and then slightly decreased to 0.02-0.03%, remaining at this level up to 40 yrs. The "cumulative" morbidity risk of DM I (population risk of development of DM I for each born individual, irrespective of family history) was found to be 0.2% for the age from 0-4 to 40 yrs. Assuming the age-specific morbidity risks of DM I after the age of 40 yrs to be the same as that at 40 yrs (0.02-0.03%), the "cumulative" morbidity risk for this type of DM from birth to 75 yrs old was estimated to be 0.36-0.44%. First incidences of DM II in the population were only observed in 20 yrs olds. The morbidity risk level for DM II at the age 20-24 yrs was found to be lower than that for DM I at this age. The risk was about the same level both for DM I and for DM II at the age 25-34 yrs, the morbidity risk levels for DM II after 35 yrs exceeding that for DM I. The "cumulative" risk of DM II by the age of 40 yrs was 0.1% for men and 0.15% for women. Analysis of familial data revealed statistically significant increase in recurrent morbidity risk in relatives only for the types of DM presented in probands.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

[Genetic determination of spontaneous and induced dominant lethality in Drosophila].

Estimation of heritability ha2 index in experiments on spontaneous and induced dominant lethality gives the possibility to evaluate with sufficient accuracy genetic determination of the effect and its dependence on casual reasons. Besides, the individual breeding method gave quite stable data both on late embryonic lethality index and on heritability value. Directed selection of different test-objects (species or stocks of Drosophila) should be carried out using heritability index, since selection efficiency mostly depends on this value degree. Making stocks resistant and sensitive to certain mutagen classes, their comparison from the point of view of their pharmacogenetic features, on the basis of the indices used, may be taken as the start of studies aimed at further identification of certain biochemical factors or system taking part in manifestation of mutagenic effect. The data obtained permit us to suggest an idea of advisability of studying the genetic control of mutagenesis in humans using the method described.

Animals↗
PubMed1989

[Genetic-epidemiologic analysis of uterine myoma: assessment of repeated risk].

The results of myoma uteri family analysis are presented. Average estimates of family risks were: 26.6% for proband's sisters, 19.73% for proband's daughters (up to 44-years-old), 15.81% for proband's mothers. The estimate of heritability of the disease calculated according to the sibs data was 0.792 +/- 0.018, which points to the essential role of hereditary factors in the development of myoma uteri. The table of recurrence risk was calculated on the basis of the data obtained which may be used for forming risk groups in the course of mass physical examination.

Adult↗
PubMed1989

[Genetic analysis of the predisposition to uterine myoma. Prevalence and morbidity].

Prevalence of uterine myoma (MU) was estimated in several Moscow districts. The overall average estimate of the MU prevalence is 2.45% among women of all groups. The prevalence MU estimates increase with the age, its maximum value reaching 8.31% at the age of 50 years. The morbidity risk estimates increased with the age as well, the maximum value being 2.98% at the age of 40-44 years. The value of "cumulative" morbidity risks, i. e. the probability to be affected, is 9.74% for a population living long enough, this value being based on the age-specific estimates of morbidity risks. Taking into consideration the autopsy data, indicating that frequency of MU, including small myomatous nodes, is 20%, the conclusion is made that MU is manifested by clinically expressed disturbances (urging a woman to address to a doctor) in 50% of cases only. Epidemiological data obtained are to be used later for genetic analysis of familial data on MU.

Adult↗
PubMed1987

[Biochemical polymorphism of serum cholinesterase in populations of the Kurdamir region of the Azerbaijan SSR].

Examination of 933 schoolchildren in the Kyurdamir district of Azerbaijan for the carriage of abnormal variants of serum cholinesterase (EC 3.1.1.8.) revealed high biochemical polymorphism of the enzyme. This was conditioned by high frequencies of mutant alleles of the E1-E1a and E1s loci responsible for atypical and "silent" enzyme variants. The cases of confusions of phenotypes of different heterozygotes are being analyzed using the material on pedigrees. Two types of the normal alleles (E1u)--E1u1 and E1u2--were shown to be present in the population analyzed.

Adolescent↗
PubMed1987

[Association of mutant alleles of serum cholinesterase with various multi-factorial and infectious diseases].

Polymorphism of serum cholinesterase (SCE, acylcholinacylhydrolase, EC 3.1.1.8) for the E1 locus was studied in the groups of the patients affected with schizophrenia, peptic ulcer, hereditary erythrocytopathies, tuberculosis, thyreotoxicosis, essential hypertension and rheumatic disease. Increased frequencies of I phenotypes (E1uE1a genotype) were found among patients with peptic ulcer (12.3%), hereditary erythrocytopathies (23.2%), and UF phenotypes (E1uE1f genotype) were observed among patients with schizophrenia (2.8%) and tuberculosis (5.4%). The increased frequencies of E1a and E1f alleles in these groups of patients were, as compared to the control group, statistically significant. The value of relative risk for peptic ulcer was 3.39 in individuals of the E1uE1a genotype, those being 3.62 for schizophrenia and 6.92 for tuberculosis in individuals of the E1uE1f genotype. The nature of the other associations is discussed.

Alleles↗
PubMed1986

[Genetic analysis of the structure of predisposition to diabetes mellitus. III. Genetic heterogeneity of diabetes mellitus with different ages of onset].

The results of genetical-epidemiological analysis of the three conventional forms of diabetes mellitus (DM) differentiated for age-at-onset are presented (the form I - from 0 to 29 y. the form II - from 30 to 59 y. the form III - 60 y. and older). The estimates of heritability of liability to the forms I, II and III of DM were 0.57, 0.70 and 0.65, respectively. It was shown that genetic components of the forms I and II are virtually different: genetic correlation between these forms was rA = 0.216 +/- 0.203, which is statistically insignificant. These data support the hypothesis assuming genetic independence of juvenile and adult forms of DM. On the other hand, the forms II and III were found to have an essential number of genes in common: genetic correlation was rA = 0.495 +/- 0.134, being significant at the 5% level. Thus, the forms II and III of DM are not to be considered as two genetically distinct diseases. The low recurrence risks of the form I for siblings (not more than 3.6%) allow to reject the hypothesis of simple monogenic inheritance of juvenile DM and to propose multifactorial nature of the disease.

Adolescent↗
PubMed1985

[Genetic analysis of the indices of gastric acid secretory and proteolytic functions in duodenal ulcer patients].

The phenotypic correlations between pepsinogen, proteases and the debit of acid secretion in patients with the peptic ulcer of duodenum and their parents were studied. It was found that the genetic factors have great influence on the level of pepsinogen and proteases in the basal conditions and under stimulation. In comparison with the general population, we obtained highly reliable increase of the level of pepsinogen and proteases in the groups of patients and their parents.

Adolescent↗