Disease relevance of Twin Studies

• Knowledge about the balance between heritable and nonheritable risk in multiple sclerosis (MS) is based on twin studies in high-prevalence areas [1].
• Heritability of type II (non-insulin-dependent) diabetes mellitus and abnormal glucose tolerance--a population-based twin study [2].
• Family and twin studies showed that besides HLA-B27 other genetic factors are of significance for the pathogenesis of ankylosing spondylitis, reactive arthritis or acute anterior uveitis [3].

Psychiatry related information on Twin Studies

• Although the etiology of attention-deficit/hyperactivity disorder (ADHD) is likely multifactorial, family, adoption, and twin studies suggest that genetic factors contribute significantly [4].
• CO2-induced panic attacks: a twin study [5].
• A twin study of late-onset depression and apolipoprotein E epsilon 4 as risk factors for Alzheimer's disease [6].
• A twin study on three enzymes (DBH, COMT, MAO) of catecholamine metabolism. Correlations with MMPI [7].
• Gilles de la Tourette Syndrome (GTS) has long been known to be familial, and evidence from twin studies indicates that it has a substantial genetic component [8].

High impact information on Twin Studies

• Abundant epidemiological data, including family and twin studies, point to a strong genetic influence on the development of AITD [9].
• Twin study links genes to homosexuality [10].
• The twin study, designed to determine the relative contributions of genetic and environmental factors to large interindividual variation in theophylline elimination, revealed predominantly genetic control [11].
• CONTEXT: Twin studies using selected samples have shown high heritability for Alzheimer disease (AD) [12].
• PARTICIPANTS: More than 5000 members of male-male and female-female twin pairs from the Virginia Adult Twin Study of Psychiatric and Substance Use Disorders [13].

Biological context of Twin Studies

• The effect of the apolipoprotein E phenotype on plasma lipids is not influenced by environmental variability: results of a Dutch twin study [14].
• Evidence for genetic determinants on nicotine use and effects is presented using data from twin studies and from molecular genetic research with humans and animals [15].
• This, along with evidence for a genetic diathesis provided by family and twin studies, prompted us to conduct genetic association studies of dopamine system genes in OCD [16].
• Unlike the large literature on the prevalence and consequences of tobacco use, there are fewer data on the genetic epidemiology (family, adoption, and twin studies) of tobacco use initiation and nicotine dependence [17].
• A twin study of cytogenetic variability. Progress report [18].

Anatomical context of Twin Studies

• Lithium accumulation in erythrocytes of manic-depressive patients: an in vivo twin study [19].
• Although conclusive data about the precise genetic control obtainable in twin studies are still missing, we would suggest that elevated lymphocyte spiperone binding may be a marker of susceptibility to schizophrenia [20].
• Genetic control of serotonin uptake in blood platelets: a twin study [21].

Associations of Twin Studies with chemical compounds

• DESIGN: Classic twin study [22].
• Genetic determinant of lithium ion distribution. An in vitro and in vivo monozygotic-dizygotic twin study [23].
• Twin study of genetic and environmental influences on glucose tolerance and indices of insulin sensitivity and secretion [24].
• Our twin study also indicates that the angiotensin-converting enzyme gene locus is genetically linked to posterior wall thickness [25].
• A role for external factors is indicated by twin studies, and the role of aluminium is currently under investigation [26].

Gene context of Twin Studies

• This fact is most clearly seen in the 20 extant twin studies, which estimate the heritability of ADHD to be .76 [27].
• A twin study for serum leptin, soluble leptin receptor, and free insulin-like growth factor-I in pubertal females [28].
• We hypothesised that this gene might be implicated in the development of VV in the normal population, therefore, after performing a classical twin study, we tested for linkage and association in white women [29].
• METHODS AND RESULTS: The heritability of CRP, fibrinogen, sICAM-1, IL-6, and TNF-alpha was determined in a twin study consisting of 129 monozygotic twin pairs and 153 dizygotic same-sex twins aged 73 to 94 years who participated in the Longitudinal Study of Aging of Danish Twins [30].
• A recently reported, association of a HTR2A polymorphism with episodic memory in young unrelated adults led us to investigate the association between a nearby polymorphism and longitudinal memory performance in the Swedish Adoption/Twin Study of Aging (SATSA) [31].

Analytical, diagnostic and therapeutic context of Twin Studies

• Comparisons are made to results from similar twin studies and the first examination of the NHLBI Twin Study. Heritability estimates for phosphorus and blood urea nitrogen exhibited marked stability across studies, while heritability estimates for total bilirubin, total protein, and uric acid decreased in older study populations [32].
• Fasting plasma cortisol was lower in the study compared to the control group (266 +/- 16 vs. 341 +/- 28 nmol/L, p < 0.01) due to the influence of the twin study subgroup [33].

References