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Results for “polygenicity”

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At least 343 records · Page 19Linked to original sources
PubMed1995

Polymorphism and peripheral levels of apolipoprotein(a) in polygenic hypercholesterolemia and combined hyperlipidemia.

This study demonstrates that peripheral apolipoprotein(a) [apo(a)] levels are higher in patients with polygenic hypercholesterolemia (PH) and combined hyperlipidemia (CH) than in controls. Levels of apo(a) inversely correlate with apo(a) isoform sizes. For a given apo(a) isoform, apo(a) levels are higher in PH and CH patients. Higher frequencies of smaller apo(a) isoforms were found in PH and CH patients than in controls, and in patients with coronary artery disease (CAD) or a family history of premature cardiovascular diseases than in patients without CAD or family history.

Adult↗
PubMedDate not supplied

[Non-specific polygenic regulation of antibody synthesis].

Four two-way genetic selections of outbred mice for the quantitative character "agglutinin production" to heterologous erythrocytes and flagellar or somatic antigens of Salmonella are briefly described. The principal genetic parameters regulating the quantitative antibody response are the following: 1) the character is polygenic; the number of independent loci is estimated between 7 and 16; 2) the heritability of the character (h2) is comprised between 0.17 and 0.21; 3) the maximal interline separation RT (4.8-7.8 log2) is reached after about 15 consecutive generations of selective breeding; (4) the rate of interline separation/generation RG is 0.32-0.48 log2. 5) The phenotypic variance V(P) of the foundation populations is due for 52%-63% to genetic factors V(G) and for 37%-48% to environmental factors V(E); 6) The effect of the selective breeding is essentially non-specific; it modifies the antibody responsiveness to many unrelated complex immunogens.

Agglutinins↗
PubMed1996

Polygenic inheritance of predisposition to lung cancer.

Inherited predisposition to lung tumor development appears to be a complex genetic trait, in humans as well as in experimental animals. In humans, tobacco smoking represents the main risk factor for lung tumors. Familial clusterings of lung cancer cases are rare, although affected sib pairs are reported. However, several studies have reported an increased risk of lung cancer in first degree relatives of lung cancer patients, as compared with appropriate controls. Inheritence of particular alleles of genes or phenotypes for drug metabolizing enzymes are also associated with an increased lung cancer risk. In experimental models, murine inbred strains with high genetic predisposition to lung cancer are available, as well as resistant strains. A major locus affecting inherited predisposition to lung cancer in mice has been mapped on chromosome 6, near the Kras2 gene. The locus, pulmonary adenoma susceptibility 1 (Pas1) derives from the A/J strain. Additional "minor" loci have also been mapped. Dominant lung tumor resistance loci have also demonstrated in the mouse genome. Therefore, evidence for polygenic inheritance of predisposition to lung cancer is demonstrated in the mouse model, and it is strongly suggested for human lung cancer.

Adenocarcinoma↗
PubMed1997

Identification of polygenic disease genes.

I discuss the identification and cloning of genes involved in determining susceptibility to diseases under polygenic control. The process of cloning a susceptibility gene is as follows: identification of new genetic markers in the region by database analysis, isolation of DNA clones in the region and the generation of new genetic markers, refinement of the map position using these markers for linkage disequilibrium analysis, construction of a physical and disequilibrium map, construction of a clone contig across the critical region in yeast artificial chromosomes, PAC, bacterial artificial chromosomes and cosmids, and finally gene identification and etiological mutation detection.

Chromosome Mapping↗
PubMed1997

Molecular genetic studies in monogenic and polygenic human diseases.

The main goal of this study was to determine and characterise the types of mutations in two monogenic human disorders: cystic fibrosis (CF) and Duchenne/Becker muscular dystrophy (DMD, BMD) and the susceptibility allele frequency in a polygenic disease: type I insulin-dependent diabetes mellitus (IDDM). After analysing 220 chromosomes for mutations in the CF (Cystic Fibrosis Transmembrane Conductance Regulator = CFTR) gene, delta F508 mutation was most abundant (41%) and out of the non-delta F508 CF mutations 5% was identified as G542X, G551D, R553X, N1303K and W1282X. The CF haplotype analysis by using linked markers to the CFTR gene revealed that the CF "B" haplotype occurred in 66.7% of patients, and this haplotype was 57.2% in patients carrying the delta F508 mutation. Prenatal genetic diagnosis for CF was performed in 10 fetuses: 3 were affected, 6 were carriers, and 1 without any CF mutation. Fifty % of 66 patients with DMB/BMD muscular dystrophy had one or more exon deletions in the dystrophin gene. Eighty-five % of the deletions occurred at the 3' and 15% at the 5' end of the gene. Out of the three prenatal diagnosis in one case DMD was substantiated. Thirty-six % of 50 patients with IDDM possessed four, 44% three and 20% two susceptibility markers in the HLA-DQA1, -DQB1 region. The onset of the disease correlated with the number of susceptibility alleles.

Alleles↗
PubMedDate not supplied

Cleft lip and palate etiology and its meaning in early 20th century England: Galton/Pearson vs. Bateson; polygenically poor protoplasm vs. Mendelism.

At the outset of the 20th century in England there arose a venomous dispute between Mendelian geneticists such as Bateson and anti-Mendelian biometricians such as Pearson over the genetic etiology of such "physical deformities" as cleft lip and palate. To Pearson et al., such traits were an expression of physical and racial degeneracy which could be traced to polygenically poor protoplasm. To Bateson et al., such traits were Mendelian unit characters whose segregation could be seen in carefully constructed family pedigrees. Bateson dismissed the work of the anti-Mendelians as "unsound in construction" and predicted such thinking would inevitably lead to "brutal" control of those the larger society deemed unfit. History proved Bateson astutely prescient.

Cleft Lip↗
PubMed1998

[Identification of polygenes in the system achaete-scute in Drosophila melanogaster using cluster analysis].

Data on location of mobile elements mdg1, Dm412, copia, and B104 in 33 isogenic lines of Drosophila melanogaster has been processed by means of cluster analysis to reveal the relationship between the penetrance for bristle reduction and the distribution of mobile elements. The presence of two groups of sites specific for lines with contrasting penetrance levels have been demonstrated. The specificity suggests that the sites can be associated with the location of corresponding polygenes, affecting the penetrance level in mutant lines.

Animals↗
PubMed1998

Environment-influenced expression of polygene mutations isolated from a natural population of Drosophila melanogaster.

Quantitative trait loci (QTLs) affecting sternopleural bristle number in Drosophila melanogaster have been mapped using phenotypic markers and progeny testing. The loci were found on four of the third chromosomes isolated from a natural population. All four loci showed large effects at the standard 25 degrees C culture temperature, but they responded in different ways when developmental temperature was lowered or raised. These data support the hypothesis that genotype x environment interactions have important influences on polygene expression, and some loci might be silent, or phenotypically neutral, under some conditions but play a large phenotypic role under others. Thus, a full cataloging of the loci contributing to mutational variance for QTLs cannot be done at just a single, controlled environmental condition.

Animals↗
PubMedDate not supplied

[Hybridologic analysis according to polygenic traits].

A method is suggested for hybridological analysis of polygenic characters based on comparing the hybrid generation's arithmetical mean components with genotypic dispersion. The method allows determining the number of genes by which parental forms differ, type and value of the gene interaction. On this basis it is possible to predict splitting off definite genotypes as well as to plan ratiis is available.

Genes↗
PubMed1998

[Specific features of cardiovascular diseases in patients with mono- and polygenic types of dyslipoproteinemia].

Atherosclerosis as a key factor of cardiovascular morbidity and mortality is one of the most pressing problem of modern medicine. Most phenotypic deviations of serum cholesterol levels are genetically predetermined and the influence of environmental factors is much less. The vast majority of hereditary dyslipoproteinemia are polygenic. Monogenic disorders are seen in a small proportion of patients with atherosclerosis. However, they only emphasizes the carriage of alleles of the genes that determine various aspects of lipid genesis, transport, and predisposition to atherosclerosis. Virtually all primary dyslipoproteinemias appear as atherogenic types and they represent a special form of atherosclerosis. This fact affects the specific features of cardiovascular diseases in patients with hereditary hyperlipidemias. In these patients coronary heart disease as the most common manifestation of atherosclerosis occurs just in infancy, it is malignant and progressive and unresponsive to treatment. Furthermore, there is a drastic increase in the likelihood of a menacing and fatal complication, such as sudden death. For therapeutical and preventive purposes, these all factors make it necessary to perform a comprehensive early diagnosis of hereditary dyslipoproteinemias by using clinical, genealogical and routine studies, followed by correction of the disorders detected.

Arteriosclerosis↗
PubMed1998

Hemorheological changes in children with polygenic hypercholesterolemia.

In order to ascertain whether polygenic hypercholesterolemia (PH), the most common cause of small increases in plasma lipids during childhood, is associated with rheological alterations, we determined the hemorheological and lipid profile of 21 PH children (12 males, 9 females) and a well-matched control group (CG). In addition, a carotid ultrasound was done on all the PH children, but showed no alterations. When compared with the CG, PH children showed increased erythrocyte aggregation both at stasis (EAM0) (4.39+/-1.15 vs. 3.75+/-1.02), p < 0.05, and at low shear rate (EAM1) (8.22+/-1.42 vs. 7+/-1.39), p < 0.01, and increased plasma viscosity (PV) (1.19+/-0.04 cP vs. 1.15+/-0.04 cP), p < 0.01. These results reinforce the hypothesis that lipid metabolic alterations are associated with specific rheological modifications in absence of a demonstrable atherosclerotic lesion.

Apolipoproteins↗
PubMed1998

[From monogenic to polygenic: model of Hirschsprung disease].

Hirschsprung's disease (HSCR, aganglionic megacolon) is a frequent congenital malformation regarded as a multigenic neurocristopathy. Three susceptibility genes have been recently identified in HSCR, namely the RET proto-oncogene, the endothelin B receptor (EDNRB) gene, and the endothelin 3 (EDN3) gene. RET gene mutations were found in significant proportions of familial (50%) and sporadic (15-20%) HSCR, while homozygosity for EDNRB or EDN3 mutations accounted for the rare HSCR-Waardenburg syndrome (WS) association. More recently, heterozygous EDNRB and EDN3 missense mutations have been reported in isolated HSCR patients. Some of these results were obtained after the identification of mouse genes whose natural or site-directed mutations resulted in megacolon and coat color spotting. There is also conclusive evidence for the involvement of other independent loci in HSCR. In particular, the recent identification of neurotrophic factors acting as RET ligands (GDNF and Neurturin) provide additional candidate genes for HSCR. The dissection of the genetic etiology of HSCR disease may then provide a unique opportunity to distinguish between a polygenic and a genetically heterogeneous disease, thereby helping to understand other complex disorders and congenital malformations hitherto considered as multifactorial in origin. Finally, the study of the molecular bases of HSCR is also a step towards the understanding of developmental genetics of the enteric nervous system giving support to the role of the tyrosine kinase and endothelin-signaling pathways in the development of neural crest-derived enteric neurons in human.

Animals↗
PubMed2025

Psychological and emotional impacts of communicating breast cancer risk using multifactorial assessment with polygenic risk score: Findings from PERSPECTIVE I&I.

PURPOSE: To examine the psychological and emotional outcomes of personalized breast cancer risk communication up to 1 year after disclosure in a risk-stratified breast screening preimplementation study (Personalized Risk Assessment for Prevention and Early Detection of Breast Cancer: Integration and Implementation). METHODS: Among 3753 females aged 40 to 69, unaffected by breast cancer, with a prior mammogram, and who underwent multifactorial risk assessment to estimate their 10-year breast cancer risk, 2734 completed follow-up questionnaires up to 1 year after risk communication: 78.5% were at average risk, 16.5% at higher than average risk, and 5.0% at high risk. The impact of risk communication on breast cancer worry and psychological distress and factors associated with decisional regret were examined. RESULTS: Breast cancer worry and psychological distress scores remained low after risk communication and at 1 year follow-up. Up to 1 year after disclosure, small significant differences in breast cancer worry were observed between risk levels. Decisional regret was very low 1 year after risk communication. Lower levels of decisional regret were significantly associated with some factors, including higher satisfaction with the information received. CONCLUSION: This study suggests that personalized breast cancer risk communication has low negative psychological and emotional effects and highlights the importance of the information received for implementing this approach at population level.

Humans↗
PubMed1997

Matrix attachment regions and transcription units in a polygenic mammalian locus overlapping two isochores.

Eukaryotic chromosomes are ponctuated by specialized DNA sequences (MARs) characterized by their ability to bind the network of nonhistone proteins that form the nuclear matrix or scaffold. We previously described an amplifiable cluster of genes with different tissue-specific expression patterns, located on Chinese hamster chromosome 1q. This model is especially appropriate to study the relationships between MARs and transcription units. We show here that four attachment regions, with sequences exhibiting motifs specific to MARs, are present within the 100 kb of screened DNA. Three of them are relatively short sequences localized in intergenic regions. The last one extends over one of the transcription units and contains a region previously identified as a recombination hot spot. Moreover, the analysis of a DNA sequence extending over some 50 Kb of this region and spanning at least four genes, disclosed a strikingly sharp change in G + C content. This strongly suggests that the studied region contains the boundary of two isochores. We propose that the frequency and the size of MARs are correlated to their localization in G + C rich or poor domains.

Amino Acid Sequence↗
PubMed1990

The problem of polygenic disease.

Most diseases have a genetic component. In those caused by a mutation at a single locus and with a clear phenotype (Mendelian disorders) the molecular genetics approach is relatively simple. The identification and cloning of the mutated gene leads to a complete analysis of the underlying molecular pathology and usually explains variation in incidence and severity. However, most adult diseases are not of this type. Coronary heart disease, cancer, diabetes, arthritis and mental illness all have a genetic component but are rarely inherited in a Mendelian fashion. Multifactorial diseases have both genetic and environmental components which contribute in different proportions in a given patient or family. The genes involved may exert additive effects, or act synergistically. Other cases of the same disease may be entirely environmental in their causation. Molecular genetics facilitates investigation of the number of genes involved in cases of multifactorial disease, their relative weight in different families and in the community, and the nature of their interaction. One particularly powerful approach is to study a large family in which simple Mendelian segregation occurs for a disease which is more often complex or sporadic.

Coronary Disease↗