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A population-based study of multiple sclerosis in twins: update
A D Sadovnick1, H Armstrong, G P Rice
1University of British Columbia, Vancouver, Canada.
Annals of Neurology
|March 1, 1993
Summary
Genetic factors influence multiple sclerosis (MS) susceptibility, but nonheritable factors play a significant role. Most identical twins with MS remain discordant, highlighting environmental impacts.
Area of Science:
- Neuroimmunology
- Genetic Epidemiology
- Twin Studies
Background:
- Multiple sclerosis (MS) is a chronic autoimmune disease affecting the central nervous system.
- Understanding the interplay of genetic and environmental factors in MS etiology is crucial for developing effective prevention and treatment strategies.
- Twin studies provide a unique model to disentangle heritability and shared environmental influences.
Purpose of the Study:
- To investigate the long-term concordance rates in a population-based series of twins with multiple sclerosis (MS).
- To further elucidate the genetic and environmental contributions to MS susceptibility.
- To assess the role of nonheritable factors in MS development.
Main Methods:
- A 7.5-year follow-up of a population-based twin cohort with MS, identified through the Canadian nationwide system of MS clinics.
- Analysis of concordance rates in monozygotic (MZ) and dizygotic (DZ)-like twin pairs.
- Inclusion of age and magnetic resonance imaging (MRI) findings in the analysis.
Main Results:
- The MZ twin concordance rate for MS increased from 25.9% to 30.8% over the follow-up period.
- The DZ-like sex concordance rate increased from 2.4% to 4.7%.
- A significant proportion of MZ twin pairs remained discordant for MS, even after adjusting for age and MRI findings.
Conclusions:
- MS susceptibility is influenced by genetic factors, likely involving multiple genes rather than a single dominant or recessive gene.
- Nonheritable, environmental factors play a powerful role in MS etiology, as evidenced by the discordance in MZ twins.
- These findings underscore the complex interaction between genetic predisposition and environmental triggers in the development of multiple sclerosis.