The genetic background of circadian and ultradian rhythm patterns of 17-hydroxycorticosteroids: a cross-twin study

ABSTRACT Circadian and ultradian rhythms in urinary excretion of 17-hydroxycorticosteroids were documented individually during an 8-day span in two pairs of young male twins. Studies were performed once at the age of 6 years for dizygotic twins and twice at the ages of 4·3 and 10·3 years for monozygotic twins. Four different methods were used for time-series analyses: chronograms (raw data), best-fitting curves resulting from cosinor analyses, power spectra and correlations of time-qualified data. Estimates of rhythm parameters (prominent periods, acrophases, etc.) as well as shapes of curves were closer in mono- than in dizygotic twins. Both similarities and small differences in rhythm characteristics of monozygotic twins were detected at both ages considered. J. Endocr. (1985) 105, 247–253

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A REVIEW OF GENETIC FACTORS IN DEPRESSIVE AFFECTS

Social Behavior and Personality An International Journal ◽

10.2224/sbp.2003.31.7.657 ◽

2003 ◽

Vol 31 (7) ◽

pp. 657-662 ◽

Cited By ~ 1

Author(s):

Shahuria Enam

Keyword(s):

Twin Study ◽

Genetic Factors ◽

Monozygotic Twins ◽

Linkage Relationship ◽

Genetic Transmission ◽

Affective Illness ◽

Dizygotic Twins ◽

Research Findings ◽

Phenotypic Variations ◽

Bipolar Patients

This paper contains a review of genetic factors in depressive affects. A large number of research findings have been reported for this purpose, the most important of these being the twin study. Monozygotic and dizygotic twins have been differentiated. It has been found that monozygotic twins have a higher concordance rate for affective illness than do dizygotic twins. Moreover, bipolar and unipolar illnesses were found in the relatives of unipolar patients only. Thus affective illness in the first degree of relatives of bipolar patients was more than 30%. Genetic transmission was also found in linkage relationship. Chromosomal studies have also been reported. Phenotypic variations have also been found to be responsible for affective illness. In conclusion, a better clinical, biochemical, and therapeutic investigation has been suggested for better understanding of genetic factors in affective illness.

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Genetic background of the multifactorial liver and bile duct diseases

Orvosi Hetilap ◽

10.1556/oh.2007.27987 ◽

2007 ◽

Vol 148 (4) ◽

pp. 147-153

Author(s):

Krisztina Hagymási ◽

Zsolt Tulassay

Keyword(s):

Genetic Background ◽

Liver Diseases ◽

Genetic Factors ◽

Familial Aggregation ◽

Monozygotic Twins ◽

Accurate Diagnosis ◽

Disease Course ◽

Limited Data ◽

Bile Duct Diseases ◽

Dizygotic Twins

The majority of liver diseases, are complex. They are the results of interactions between several genes and environmental factors. Familial aggregation and higher concordance rate of monozygotic twins compared to those of dizygotic twins provide evidence for the importance of genetic factors in the pathogenesis. There are only limited data in connection with the genetic background of multifactorial liver diseases. In the future, the genetic background may permit prevention, early, accurate diagnosis, prediction of disease course, complications, prognosis, as well as treatment response.

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The Role of Negative Personality Traits in Psychological Adaptation

Russian Foundation for Basic Research Journal Humanities and social sciences ◽

10.22204/2587-8956-2018-092-03-115-125 ◽

2019 ◽

pp. 115-125

Author(s):

Юлия Черткова ◽

Yuliya Chertkova ◽

Марина Егорова ◽

Marina Yegorova

Keyword(s):

Life Satisfaction ◽

Personality Traits ◽

Twin Study ◽

Monozygotic Twins ◽

Psychological Adaptation ◽

Semantic Differential ◽

Personal Traits ◽

Only Children ◽

Age Related

The paper reflects one of the aspects of the research carried out within the framework of the project “Nature of variability of negative personality traits: a twin study”. The research reviews the adaptive component of negative personal traits. The sample of the study consisted of 136 members of monozygotic twins and 401 only children in their families aged 18-78. Life satisfaction was a generalized metric of psychological adaptation. It is shown that a number of negative personality traits (in particular, narcissism, authoritarianism) positively correlate with life satisfaction. The biased value of various personality traits, which can also indirectly serve as an indicator of adaptability of these psychological properties, was assessed using a semantic differential. The age-related changes in the perfect image of the self, which are associated primarily with some more attractive negative personal traits, as well as the multidirectional desired changes in personality traits in themselves and the twin (more power and conflict in themselves and less of the same in the brother/sister) also indicate that a number of negative personal traits play a positive role in psychological adaptation. It is assumed that these traits can have a compensatory function during stress, and the destructiveness of these traits can have a greater impact on people around than on themselves.

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Does Higher Concordance in Monozygotic Twins Than in Dizygotic Twins Suggest a Genetic Component?

Human Heredity ◽

10.1159/000053333 ◽

2001 ◽

Vol 51 (3) ◽

pp. 121-132 ◽

Cited By ~ 23

Author(s):

Sun-Wei Guo

Keyword(s):

Monozygotic Twins ◽

Genetic Component ◽

Dizygotic Twins

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Tacit coordination in monozygotic twins, dizygotic twins and virtual twins: Effects and implications of genetic relatedness

Personality and Individual Differences ◽

10.1016/j.paid.2008.06.022 ◽

2008 ◽

Vol 45 (7) ◽

pp. 607-612 ◽

Cited By ~ 13

Author(s):

Nancy L. Segal ◽

Shirley A. McGuire ◽

Steven A. Miller ◽

June Havlena

Keyword(s):

Genetic Relatedness ◽

Monozygotic Twins ◽

Dizygotic Twins ◽

Tacit Coordination

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Influence of heritability on craniofacial soft tissue characteristics of monozygotic twins, dizygotic twins, and their siblings using Falconer's method and principal components analysis

The Korean Journal of Orthodontics ◽

10.4041/kjod.2019.49.1.3 ◽

2019 ◽

Vol 49 (1) ◽

pp. 3 ◽

Cited By ~ 1

Author(s):

Jeongmin Song ◽

Hwa Sung Chae ◽

Jeong Won Shin ◽

Joohon Sung ◽

Yun-Mi Song ◽

...

Keyword(s):

Soft Tissue ◽

Principal Components Analysis ◽

Principal Components ◽

Monozygotic Twins ◽

Dizygotic Twins ◽

Components Analysis ◽

Tissue Characteristics

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Dentofacial Characteristics among Monozygotic and Dizygotic Twin Pairs from a Unique Village of Twins in South India: A Descriptive Cross-sectional Study

International Journal of Recent Surgical and Medical Sciences ◽

10.5005/jp-journals-10053-0033 ◽

2017 ◽

Vol 03 (01) ◽

pp. 025-028

Author(s):

Praveen Jodalli ◽

Ganesh Panchmal ◽

Vinej Somaraj ◽

Shafees Koya

Keyword(s):

South India ◽

Monozygotic Twins ◽

Twin Studies ◽

Cross Sectional Study ◽

Sectional Study ◽

Cross Sectional ◽

Factors Influencing ◽

Dizygotic Twins ◽

Cast Analysis ◽

Dental Cast

Abstract Aim: To assess the dentofacial characteristics of a mystery village of twins in South India. Materials and methods: A descriptive cross-sectional study was carried out among of 22 twin pairs (10 monozygotic twins and 12 dizygotic twins). The evaluation was done in terms of height, weight, dentofacial profile, and occlusion status based on anthropometric, photographic, and dental cast analysis. Results: Data obtained upon analysis of anthropometric measurements, photographic data, and dental cast evaluation revealed a set of characteristics peculiar to the twins of this unique village. Conclusion: Twin studies are a fascinating method of research because of their ability to correctly isolate a characteristic and determine its impact, especially in terms of dentofacial characteristics. Clinical significance: Twin research design involving the comparison of variables among monozygotic (identical) and dizygotic (fraternal) twins is a method by which researchers quantify and classify the contribution of genes and other extraneous factors influencing heredity on the dentofacial complex and dentition.

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Evidence for Genetic Factors Explaining the Association Between Birth Weight and Low-Density Lipoprotein Cholesterol and Possible Intrauterine Factors Influencing the Association Between Birth Weight and High-Density Lipoprotein Cholesterol: Analysis in Twins

The Journal of Clinical Endocrinology & Metabolism ◽

10.1210/jcem.86.11.7996 ◽

2001 ◽

Vol 86 (11) ◽

pp. 5479-5484 ◽

Cited By ~ 16

Author(s):

Richard G. IJzerman ◽

Coen D. A. Stehouwer ◽

Mirjam M. van Weissenbruch ◽

Eco J. de Geus ◽

Dorret I. Boomsma

Keyword(s):

Birth Weight ◽

Total Cholesterol ◽

Apolipoprotein B ◽

Genetic Factors ◽

Ldl Cholesterol ◽

Low Density Lipoprotein ◽

Monozygotic Twins ◽

Density Lipoprotein ◽

Hdl Cholesterol ◽

Dizygotic Twins

Recent studies have demonstrated an association between low weight at birth and an atherogenic lipid profile in later life. To examine the influences of intrauterine and genetic factors, we investigated 53 dizygotic and 61 monozygotic adolescent twin pairs. Regression analysis demonstrated that low birth weight was associated with high levels of total cholesterol, low-density lipoprotein (LDL) cholesterol and apolipoprotein B (−0.17 mmol/liter per kg, P = 0.07; −0.18 mmol/liter per kg, P = 0.04; and− 0.07 g/liter per kg, P = 0.02, respectively) and with low levels of high-density lipoprotein (HDL) cholesterol (+0.04 mmol/liter per kg, P = 0.1), after adjustment for age, sex, and body mass index. Intrapair differences in birth weight were significantly associated with differences in total cholesterol, LDL cholesterol, and apolipoprotein B in dizygotic twins after adjustment for differences in current body mass index (−0.49 mmol/liter per kg, P = 0.02; −0.51 mmol/liter per kg, P = 0.01; and −0.10 g/liter per kg, P = 0.04, respectively), demonstrating that the larger the difference in birth weight, the higher these risk factors in the twin with the lower birth weight, compared with the cotwin with the higher birth weight. In monozygotic twins, however, the associations between intrapair differences in birth weight and differences in total cholesterol, LDL cholesterol, and apolipoprotein B were in the opposite direction (+0.32 mmol/liter per kg, P = 0.03; +0.23 mmol/liter per kg, P = 0.08; and +0.06 g/liter per kg, P = 0.04, respectively). The association between intrapair differences in birth weight and differences in HDL cholesterol was not significant in dizygotic twins (+0.04 mmol/liter per kg, P = 0.6) and of borderline significance in monozygotic twins (+0.11 mmol/liter per kg, P = 0.05). These data suggest that genetic factors account for the association of low birth weight with high levels of total cholesterol, LDL cholesterol, and apolipoprotein B, whereas intrauterine factors possibly play a role in the association between birth weight and HDL cholesterol.

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Electroencephalographic Study of Mentally Retarded Twins

Australian & New Zealand Journal of Psychiatry ◽

10.3109/00048677609159494 ◽

1976 ◽

Vol 10 (2) ◽

pp. 157-162

Author(s):

Takao Hattori

Keyword(s):

Mental Retardation ◽

Brain Damage ◽

Monozygotic Twins ◽

Mentally Retarded ◽

Concordance Rate ◽

Dizygotic Twins ◽

Electroencephalographic Study

The EEGs of twenty-five pairs of twins, one or both of whom were mentally retarded, were studied. The concordance rate for mental retardation in monozygotic twins was higher than that in dizygotic twins. The vast majority of cases of mental retardation were considered to be caused by genotype but some exogenous causes were observed in discordant monozygotic twins. Paroxysmal discharges in the EEG especially those of centrencephalic type were suspected to be bio-electrical expressions of a transmissible cerebral susceptibility which may easily lead to intellectual deterioration by brain damage or epilepsy.

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