scholarly journals Twin Legacies: Victor and Vincent McKusick / Twin Studies: Twinning Rates I; Twinning Rates II; MZ Twin Discordance for Russell–Silver Syndrome; Twins’ Language Skills / Headlines: Babies Born to Identical Twin Couples; Identity Exchange; Death of Princess Ashraf (Twin); Yahoo CEO Delivers Identical Twins

2016 ◽  
Vol 19 (2) ◽  
pp. 158-162
Author(s):  
Nancy L. Segal
Keyword(s):  
Supreme Court ◽  
Language Skills ◽  
Twin Studies ◽  
Medical Genetics ◽  
Identical Twins ◽  
Identical Twin ◽  
New Mother ◽  
Biographical Account ◽  
Silver Syndrome ◽  
Mz Twins

The lives of the illustrious monozygotic (MZ) twins, Victor A. and Vincent L. McKusick, are described. Victor earned the distinction as the ‘Father of Medical Genetics’, while Vincent was a legendary Chief Justice of the Maine Supreme Court. This dual biographical account is followed by two timely reports of twinning rates, a study of MZ twin discordance for Russell–Silver Syndrome (RSS) and a study of twins’ language skills. Twin stories in the news include babies born to identical twin couples, a case of switched identity, the death of Princess Ashraf (Twin) and a new mother of twins who is also Yahoo's CEO.

Twin Studies in Medical Genetics

1976 ◽  
Vol 25 (1) ◽  
pp. 249-258 ◽  
Author(s):  
P. Propping ◽  
F. Vogel
Keyword(s):  
Representative Sample ◽  
Interindividual Variability ◽  
Case Reports ◽  
Twin Studies ◽  
Medical Genetics ◽  
Genetic Component ◽  
Systematic Method ◽  
Newborn Period ◽  
Placental Blood ◽  
Placental Blood Flow

It is the aim of twin studies to obtain results which are not only valid for twins, but apply to the whole population. Therefore the following questions have to be answered first: do twins differ from non-twins in the trait under study? Do different nongenetic factors act upon MZ and DZ twins which alter the probability of manifestation of a trait, even before birth? There are important differences in embryogenesis and placental blood flow in mono- and dichorionic twins; this can influence the normal fetal development. Therefore the value of twin studies alone in analysing the genetic component in the etiology of congenital malformations is rather ambiguous. Twin studies beyond the newborn period can be classified into four approaches: (1) Case reports; (2) Accumulated case reports; (3) Limited representative sample; (4) Unlimited representative sample. The most frequent systematic method in medical genetics is the establishment of all twins in a defined population of probands (3). Another successful application in the last few years has been in pharmacogenetics. Although no simple mode of inheritance could be discovered, it was possible to estimate the genetic component within the interindividual variability of the metabolism of certain drugs (nortriptyline, antipyrine, phenylbutazone, ethanol). Now, additional non-twin research is needed to work out single factors within the observed polygenic systems.

The Unique Contribution of Twin Studies to the Elucidation of Nongenetic Factors in Personality Development and Psychopathogenesis

1970 ◽  
Vol 19 (1-2) ◽  
pp. 299-302
Author(s):  
William Pollin
Keyword(s):  
Matched Control ◽  
Personality Development ◽  
Methodological Issue ◽  
Twin Studies ◽  
Birth Size ◽  
Unique Contribution ◽  
Genetic Studies ◽  
Personality Differences ◽  
Multidisciplinary Study ◽  
Mz Twins

Our Section in Bethesda is primarily engaged in studies of schizophrenia and personality formation. I will summarize a number of our ongoing studies, and then briefly focus on a methodological issue: the possibility of twin studies moving beyond their heretofore almost constant, very useful tie to genetic studies.We have previously reported an elaborate multidisciplinary study of a series of MZ twins discordant for schizophrenia, a smaller number of appropriately matched control twin pairs, and their families, aimed at studying nongenetic factors in the pathogenesis of schizophrenia (Pollin et al, 1965, 1966). We have described three interacting groups of variables which consistently differentiated the schizophrenic and nonschizophrenic twins in the discordant pairs (Pollin and Stabenau, 1965). These included an initial set of nongenetic constitutional differences, including birth size, vigor, and physiological competence; consequent different parental perceptions of, and relationships to, each of the twins in a given pair; and subsequent biological and life history differences, based on evolving personality differences, such as in fearfulness, competence, independence, initiative and the like, differentiating the schizophrenic index and the nonschizophrenic cotwins.

4. What are the contributions of environments and genes to intelligence differences?

2020 ◽  
pp. 50-69
Author(s):  
Ian J. Deary
Keyword(s):  
Association Studies ◽  
Twin Studies ◽  
Identical Twins ◽  
New Method ◽  
Genome Wide Association ◽  
Shared Environment ◽  
Genome Wide Association Studies ◽  
Genetic Inheritance ◽  
Genome Wide ◽  
Shared Environments

‘What are the contributions of environments and genes to intelligence differences?’ asks whether genetic inheritance and the environments people experience affect intelligence differences. Researchers use two main resources to answer this question: twins and samples of DNA. Studies of identical and non-identical twins are used to show the contributions of genes, shared environment, and non-shared environment to people’s differences in traits. Twin studies tell us that by adulthood, about two-thirds of intelligence differences are caused by how people vary in their genetic inheritance, and that both shared and non-shared environments make significant contributions to intelligence differences. The introduction of genome-wide association studies in 2011 has provided a new method of estimating the heritability of intelligence.

scholarly journals Über besondere Zwillingskonkordanzen

1956 ◽  
Vol 5 (2) ◽  
pp. 138-154
Author(s):  
Hans Grebe
Keyword(s):  
Kidney Stones ◽  
Clinical Symptoms ◽  
Identical Twins ◽  
Identical Twin ◽  
Hereditary Diseases ◽  
Congenital Dislocation ◽  
Dislocation Of The Hip

SUMMARYReport about some observations with special concordance in 4 pairs of identical twins with kidney-stones, one pair of especialy concordant allergies, hyperthyreosis and cystical-glandular hyperplastic uterus and a pair of identical twin sisters, on-concordant congenital dislocation of the hip, resistant to all therapeutic essays.The especially concordance of the demonstrated twins is to be explained, that in the cases observed by the author is to suppose a stronger effect of chief gens and a lower manner of modifying by side gens or exogen ly ten years old, with particulary factors than in the ordinary states of twins with corresponding hereditary diseases.A finally demonstrated pair of non identicaly twin brothers with same deformities of the knees and same clinical symptoms) directs, that beside the same genotypus also the same exposition may realize especially twin concordances.

Concurrent Schizophrenia-Like Psychosis in Monozygous Twins Suffering from CNS Disorder

1973 ◽  
Vol 122 (571) ◽  
pp. 675-677 ◽  
Author(s):  
Albert West
Keyword(s):  
Twin Study ◽  
Genetic Factor ◽  
Environmental Influences ◽  
Twin Studies ◽  
Identical Twin ◽  
Cerebral Dysfunction ◽  
The Relationship ◽  
Monozygous Twins

Twin studies and investigations into the relationship between schizophrenia-like psychosis and cerebral dysfunction are of considerable interest. Refinement in twin studies has led to less emphasis being placed upon the genetic factor, but the pitfalls surrounding twin techniques, especially with regard to monozygous pairs and the similarity of their environment, have led Penrose (1971) to the opinion that twin study ‘is especially useful, not for genetical researches but in assessing the effects of environmental influences which lead to discordance in identical twin pairs'.

scholarly journals Co-Twin Controls: Facioplasty / Twin Research Reviews: Congenital Anomalies; Personality and Coital Orgasmic Infrequency; Physical Activity Participation / Newsworthy: Twins, Triplets and Quads; School Legislation Update; Premature Twins in Court

2008 ◽  
Vol 11 (4) ◽  
pp. 474-477
Author(s):  
Nancy L. Segal
Keyword(s):  
Physical Activity ◽  
Congenital Anomalies ◽  
Medical Malpractice ◽  
Twin Studies ◽  
Physical Activity Participation ◽  
Activity Participation ◽  
Face Lift ◽  
State Legislation ◽  
Classroom Placement ◽  
Mz Twins

AbstractThe usefulness of monozygotic (MZ) twins for studying the efficacy of different face lift techniques is described. The data suggest that no particular procedure out of four under consideration is superior to any other. Next, reviews of recent twin studies of congenital anomalies, personality traits and coital orgasmic infrequency, and physical activity participation are presented. Finally, timely topics of public interest are also described. They include a rare birth consequence of artificial reproductive technology, an update on state legislation regarding parents' rights to decide the classroom placement of their young twins, and medical malpractice lawsuits involving premature twins.

Hypertrophic Cardiomyopathy with Shared Morphology in Identical Twins: A Case Report

2002 ◽  
Vol 47 (3) ◽  
pp. 64-65 ◽  
Author(s):  
L. Wylie ◽  
A. Ramage ◽  
D. C. MacLeod
Keyword(s):  
Case Report ◽  
Hypertrophic Cardiomyopathy ◽  
Identical Twins ◽  
Identical Twin ◽  
Asymmetric Septal Hypertrophy ◽  
Heterogeneous Expression ◽  
Septal Hypertrophy

We report the case of identical twin sisters, both with hypertrophic cardiomyopathy, and both found to have similar echocardiographic appearances in the form of asymmetric septal hypertrophy. This is unusual, in that published reports commonly describe the heterogeneous expression of this condition in twins.

scholarly journals Twin Studies in Auto-immune Disease

1994 ◽  
Vol 43 (1-2) ◽  
pp. 71-81 ◽  
Author(s):  
R.D.G. Leslie ◽  
M. Hawa
Keyword(s):  
Environmental Factors ◽  
Lupus Erythematosus ◽  
Genetic Factors ◽  
Disease Risk ◽  
Twin Studies ◽  
Identical Twins ◽  
Test Bed ◽  
Immune Mediated ◽  
Organ Specific ◽  
Insulin Dependent

AbstractImmune-mediated diseases affect up to 5% of the population and are a major cause of morbidity and mortality. These diseases can be organ specific, such as insulin-dependent diabetes (IDDM) and non-organ specific, such as Rheumatoid Arthritis (RA). Identical and non-identical twins have been used to establish whether these diseases are determined by genetic or environmental factors. The results of these studies have been collated in a new section of the Mendel Institute in Rome.Diseases included in these studies included IDDM, RA, Systemic Lupus Erythematosus (SLE), Multiple Sclerosis (MS) and Myasthenia. Striking differences in concordance rates between identical and non-identical twins in all these studies suggest that genetic factors are important in causing these diseases. All the diseases are known to be associated with HLA genes on chromosome 6 which may account for some or all of the genetic susceptibility. However, in the majority of pairs the affected twin has an unaffected co-twin. These observations suggest that non-genetically determined factors, probably environmental factors and not somatic mutations, are critical. The study of unaffected co-twins, who are at high disease-risk, has allowed the identification of changes which precede and predict the clinical disease. The immune-mediated destruction in many of these diseases is probably caused by T-lymphocytes. Twin studies have shown the importance of genetic factors in determining T-cell responses. Identical twins should, therefore, provide the perfect test bed to assess the role of T-cells in immune-mediated diseases.

Blood Ties: Chimerism Can Mask Twin Discordance in High-Throughput Sequencing

2011 ◽  
Vol 14 (2) ◽  
pp. 137-143 ◽  
Author(s):  
Yaniv Erlich
Keyword(s):  
High Throughput ◽  
High Throughput Sequencing ◽  
Disease Susceptibility ◽  
Twin Pair ◽  
Twin Studies ◽  
Sequencing Data ◽  
Hematopoietic Stem ◽  
High Throughput Sequencing Data ◽  
Genetic And Environmental Factors ◽  
Mz Twins

Twin studies have long provided a means to separate the contributions of genetic and environmental factors. A recent pioneering report by Baranzini et al. presented an analysis of the complete genomes and epigenomes of a monozygotic (MZ) twin pair discordant for multiple sclerosis. This failed to find any difference between the twins, raising doubts regarding the value of whole-genome twin studies for defining disease susceptibility alleles. However, the study was carried out with DNA extracted from blood. In many cases, the hematopoietic lineages of MZ twins are chimeric due to twin-to-twin exchange of hematopoietic stem cells during embryogenesis. We therefore wondered how chimerism might impact the ability to identify genetic differences. We inferred the blood chimerism rates and profiles of more than 30 discordant twin cases from a wide variety of medical conditions. We found that the genotype compositions of the twins were highly similar. We then benchmarked the performance of SNP callers to detect discordant variations using high-throughput sequencing data. Our analysis revealed that chimerism patterns, well within the range normally observed in MZ twins, greatly reduce the sensitivity of SNP calls. This raises questions regarding any conclusions of genomic homogeneity that might be drawn from studies of blood-derived twin DNA.

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