scholarly journals Twin-Studies on the Role of Non-Genetic Factors in T1D Pathogenesis

2017 ◽  
Author(s):  
Li-li MA ◽  
Yan-ling WU ◽  
Ying DONG ◽  
Yoshimasa TANAKA ◽  
Wen ZHANG
Keyword(s):  
Genetic Factors ◽  
Twin Studies

scholarly journals Genotype and phenotype in Alzheimer's disease

2002 ◽  
Vol 180 (2) ◽  
pp. 131-134 ◽  
Author(s):  
Clive Holmes
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Genetic Factors ◽  
Clinical Phenotype ◽  
Genetic Research ◽  
Twin Studies ◽  
Common Variants ◽  
Clinical Expression ◽  
Presenilin 2

BackgroundPatients with Alzheimer's disease show a wide variation in clinical phenotype. Genetic research has been largely concerned with the role of mutations or common variants as risk factors for the disease. Do genetic factors also influence clinical phenotype?AimsTo examine the evidence that genetic factors influence the clinical expression of the disease in addition to influencing risk.MethodA selective review was made of the key literature.ResultsMutations in three genes, coding for amyloid precursor protein, presenilin-1 and presenilin-2, and a common variation (ε4) in another gene, APOE, have been shown to lead to an earlier development of the disease. More recently, genetic association and twin studies have suggested a role for genetic factors in the development of other aspects of clinical phenotype, notably the appearance of non-cognitive symptoms.ConclusionsIn Alzheimer's disease genetic variation influences a number of aspects of clinical phenotype.

Genetics of the Hypothalamic-pituitary-adrenal (HPA) Axis - a Systemic Stress Modulator in Relation to Suicidal Behaviour

2009 ◽  
Vol 24 (S1) ◽  
pp. 1-1
Author(s):  
D. Wasserman ◽  
M. Sokolowski ◽  
J. Wasserman
Keyword(s):  
Genetic Variation ◽  
Tyrosine Hydroxylase ◽  
Hpa Axis ◽  
Suicidal Behaviour ◽  
Genetic Factors ◽  
Twin Studies ◽  
Adoption Studies ◽  
Hypothalamic Pituitary Adrenal ◽  
Systemic Stress

Suicide, a phenomenon characterised by heterogeneous and complex causes affects about one million people each year.Twin studies, adoption studies and family studies indicate the role of genetic factors in suicidal behaviours. Psychobiological hypotheses regarding suicidal behaviours involve neurotransmitters such as serotonin, norepinephrine, dopamine, and their correlation to psychological functions as well as the dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis. Whereas the genes of e.g. the 5HT system and of the key NA-biosynthesis enzyme, tyrosine hydroxylase, have been studied extensively in this context the genes in the HPA axis have only begun to be investigated.Our novel results on the genetic variation in the CRHR1 gene in connection to depression and stress among suicidal individuals and in the TBX 19 gene, which is regulated by CRH, suggest that genetic variation in the CRH-mediated regulation of the HPA axis is a factor of importance in suicidality, especially in males with depression.

scholarly journals On The Influence of Genetic Factors on the Formation of Homosexuality by Data of Twin Studies

2019 ◽  
Keyword(s):  
Sexual Orientation ◽  
Genetic Factors ◽  
Dominant Role ◽  
Monozygotic Twins ◽  
Twin Studies ◽  
Correct Selection ◽  
Genetic Determination ◽  
Dizygotic Twins

Results of twin studies are presented; these demonstrate that in a number of cases genetic effects can play a role of mild predisposing factors for the development of homosexuality, but the main part in its formation is accounted for by psychological and social factors. The opinion that genetic factors play the only and dominant role in the genesis of homosexuality does not hold water due to the fact that if it were so then their concordance for homosexuality in monozygotic twins would be 100 %, but it is not observed in reality. The studies conducted with the correct selection of examinees revealed 20 % of the concordance for homosexuality in male monozygotic twins and 24 % in female ones (Bailey, J.M., et al. Genetic and environmental influences on sexual orientation and its correlates in an Australian twin sample. J. Pers. Soc. Psychol. 78(3), 524‑536). The use of Holzinger’s formula for analyzing the obtained numerical findings demonstrated that in the above case the proportion between heritable and environmental factors for male persons was 0.2 (20 %) versus 0.8 (80 %), for female persons it being 0.15 (15 %) versus 0.85 (85 %). Earlier twin studies (Bailey, J.M., Pillard, R.C. (1991). A genetic study of male sexual orientation. Arch. Gen. Psychiatry. 48(12), 1089–1096) revealed that their concordance for homosexuality in siblings (biological brothers, who are not twins) was lower than in adopted brothers (9.2 % versus 11 %), it contradicting to the idea of genetic determination of same-sex attraction. Moreover, attention is also attracted by the fact that dizygotic male twins demonstrated a significantly higher concordance for homosexuality than siblings (22 % versus 9.2 %). But it is known that dizygotic twins, like siblings, have on an average only 50 % of common genes. If there were genetic determination, such differences would not exist; the revealed difference demonstrates environmental effects, since it is evident that family upbringing of dizygotic twins is much more similar. Also it is necessary to pay attention to the fact that the rate of homosexuality in adopted homosexual brothers (11 %) considerably exceeded recent estimations of the part of homosexuals in the general population and was actually equal to the value for siblings, once again convincingly demonstrating a significant role of the environment in the formation of sexual orientation. We should not also ignore the fact that upbringing of monozygotic twins is even more similar than that of dizygotic ones; this phenomenon can cause their larger concordance for homosexuality.

A Reexamination of the Role of Heredity in Stuttering

1977 ◽  
Vol 42 (1) ◽  
pp. 47-59 ◽  
Author(s):  
Joseph G. Sheehan ◽  
Marian Sheehan Costley
Keyword(s):  
Genetic Factor ◽  
Genetic Factors ◽  
Spontaneous Recovery ◽  
Twin Studies ◽  
Present Knowledge ◽  
Critical Examination ◽  
Substantial Evidence ◽  
Familial Incidence ◽  
Predisposing Factor

In the light of recent breakthroughs in the study of schizophrenia indicating a far stronger genetic factor than has been previously suspected, the role of heredity in stuttering is critically reexamined. Present knowledge of the role of heredity in stuttering springs from four principal data sources: (1) studies of familial incidence; (2) spontaneous recovery studies; (3) twin studies; and (4) studies of parental disfluency. It is hypothesized that the 4:1 sex ratio in stuttering may be the product of selective genetic factors. Critical examination of earlier and more recent studies leads to substantial evidence that a familial predisposing factor exists in about 25% of cases of stuttering.

Has the “Equal Environments” Assumption Been Tested in Twin Studies?

Twin Research ◽  
2003 ◽  
Vol 6 (6) ◽  
pp. 486-489 ◽  
Author(s):  
Lindon Eaves ◽  
Debra Foley ◽  
Judy Silberg
Keyword(s):  
Genetic Factors ◽  
Twin Studies ◽  
Shared Environment ◽  
Environment Interaction ◽  
Genotype X Environment ◽  
Dizygotic Twins ◽  
Equal Environments Assumption ◽  
Twin Method ◽  
Equal Environments

AbstractArecurring criticism of the twin method for quantifying genetic and environmental components of human differences is the necessity of the so-called “equal environments assumption” (EEA) (i.e., that monozygotic and dizygotic twins experience equally correlated environments). It has been proposed to test the EEA by stratifying twin correlations by indices of the amount of shared environment. However, relevant environments may also be influenced by genetic differences. We present a model for the role of genetic factors in niche selection by twins that may account for variation in indices of the shared twin environment (e.g., contact between members of twin pairs). Simulations reveal that stratification of twin correlations by amount of contact can yield spurious evidence of large shared environmental effects in some strata and even give false indications of genotype x environment interaction. The stratification approach to testing the equal environments assumption may be misleading and the results of such tests may actually be consistent with a simpler theory of the role of genetic factors in niche selection.

Epigenetic factors and molecular markers of the risk of early pregnancy losses

GYNECOLOGY ◽  
2019 ◽  
Vol 21 (3) ◽  
pp. 9-16
Author(s):  
Nataly I Frolova ◽  
Tatiana E Belokrinitskaya
Keyword(s):  
Early Pregnancy ◽  
Genetic Factors ◽  
Molecular Genetic ◽  
Pregnancy Complication ◽  
Common Complication ◽  
Epigenetic Factors ◽  
Genetic Determination ◽  
Periconceptional Period ◽  
Combined Impact

Background. Miscarriage is a common complication in early pregnancy. Current studies have shown a higher prevalence of miscarriage, ranging from 10 to 20%. The review is devoted to modern concepts of etiology and pathogenesis of early pregnancy losses. Aim. Assess the role of epigenetic factors and molecular-genetic markers in the pathogenesis and prediction of early pregnancy losses Materials and methods. In order to write this review domestic and foreign publications were searched in Russian and international search systems (PubMed, eLibrary, etc.) for the last 10-15 years. Relevant articles from the peer-reviewed literature and clinical practice guidelines were included. Results. Many recent studies have proved the contribution of various epigenetic factors to the pathogenesis of spontaneous miscarriages, and the molecular-genetic determination such kinds of pregnancy complication has been confirmed. Conclusion. The miscarriage in early gestation is driven by combined impact of epigenetic and molecular-genetic factors, as well as the presence of intergenic interactions. It is may lead to deterioration of physiological functions, and maternal pathologenic pathways could be changed as during her periconceptional period as so during the pregnancy.

Role of genetic factors in the development of hypertension in young patients with metabolic syndrome

2020 ◽  
pp. 23-32
Author(s):  
Elena Korneeva ◽  
Mikhail Voevoda ◽  
Sergey Semaev ◽  
Vladimir Maksimov
Keyword(s):  
Metabolic Syndrome ◽  
High Risk ◽  
Arterial Hypertension ◽  
Genetic Factors ◽  
Young Patients ◽  
Integrin Αiibβ3 ◽  
Ace Gene ◽  
The Metabolic Syndrome

Results of the study related to polymorphism of ACE gene (rs1799752)‎, integrin αIIbβ3, and CSK gene (rs1378942) influencing development of arterial hypertension in young patients with metabolic syndrome are presented. Hypertension as a component of the metabolic syndrome was detected in 15.0% of young patients. Prevalence of mutant alleles of the studied genes among the examined patients was quite high, so homozygous DD genotype was found in 21.6%, and mutant D allele of the ACE gene in 47.4%. A high risk of hypertension in patients with MS was detected in carriers of the T allele of the CSK (rs1378942) gene – 54.8%, which was most often observed in a combination of polymorphic ACE and CSK gene loci (p = 0.0053).

scholarly journals Genetic Determinants of Paget’s Disease of Bone

2021 ◽  
Author(s):  
Navnit S. Makaram ◽  
Stuart H. Ralston
Keyword(s):  
Genetic Factors ◽  
Association Studies ◽  
Paget’S Disease ◽  
Paget's Disease ◽  
Paget’S Disease Of Bone ◽  
Genome Wide Association Studies ◽  
Paget's Disease Of Bone ◽  
Genome Wide ◽  
Family Based

Abstract Purpose of Review To provide an overview of the role of genes and loci that predispose to Paget’s disease of bone and related disorders. Recent Findings Studies over the past ten years have seen major advances in knowledge on the role of genetic factors in Paget’s disease of bone (PDB). Genome wide association studies have identified six loci that predispose to the disease whereas family based studies have identified a further eight genes that cause PDB. This brings the total number of genes and loci implicated in PDB to fourteen. Emerging evidence has shown that a number of these genes also predispose to multisystem proteinopathy syndromes where PDB is accompanied by neurodegeneration and myopathy due to the accumulation of abnormal protein aggregates, emphasising the importance of defects in autophagy in the pathogenesis of PDB. Summary Genetic factors play a key role in the pathogenesis of PDB and the studies in this area have identified several genes previously not suspected to play a role in bone metabolism. Genetic testing coupled to targeted therapeutic intervention is being explored as a way of halting disease progression and improving outcome before irreversible skeletal damage has occurred.

scholarly journals Genetic aspects of susceptibility to multiple myeloma

Blood ◽  
1982 ◽  
Vol 59 (6) ◽  
pp. 1286-1291 ◽  
Author(s):  
H Ludwig ◽  
W Mayr
Keyword(s):  
Multiple Myeloma ◽  
Patient Group ◽  
Genetic Factors ◽  
Blood Groups ◽  
Abo Blood Groups ◽  
Hla Association ◽  
Large Patient

Abstract An up-dated survey of the information pertaining to the role of genetic factors in susceptibility to multiple myeloma is attempted. Our own results include the HLA-A, B, and C types in 68 patients, the G1m and Km allotypes in 86 patients, and the frequencies of ABO blood groups in 126 patients with multiple myeloma. The allotype G1m(x) was significantly (p less than 0.05) more frequent in the patient group. Since the results in the literature on a possible HLA association have been inconsistent, all relevant available data were combined for an assessment of 379 patients versus 5041 controls. In this comparatively large patient group, the previously reported increase of HLA-4c (HLA-B5 + B18 + Bw35) complex could be confirmed and identified as a weak (RR = 1.7) but significant (p less than 0.05) association of susceptibility to multiple myeloma with HLA-B5. Evaluation of G1m allotypes in the combined sample of 258 patients and 4550 controls and Km in 179 and 2457, respectively yielded no significant differences.

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