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DR2-positive monozygotic twins discordant for narcolepsy
T Pollmächer1, H Schulz, P Geisler
1Max Planck Institute for Psychiatry, Munich, F.R.G.
Sleep
|August 1, 1990
Summary
Narcolepsy likely results from multiple factors, not just genetics. Twin studies show environmental influences alongside human leukocyte antigen (HLA) DR2 in narcolepsy development.
Area of Science:
- Neurology
- Genetics
- Sleep Medicine
Background:
- Narcolepsy exhibits familial clustering, with human leukocyte antigen (HLA) DR2 identified as a significant genetic marker.
- Family studies suggest that genetic predisposition alone does not fully explain narcolepsy's cause, indicating other contributing factors.
Purpose of the Study:
- To investigate the pathogenetic model of narcolepsy by examining monozygotic twins and their relatives.
- To differentiate between multigenetic and multifactorial models of narcolepsy through twin and family studies.
Main Methods:
- Clinical assessment and sleep polygraphy were performed on two pairs of monozygotic twins and their first-degree relatives.
- Multiple sleep latency tests (MSLT) and night sleep recordings were utilized to evaluate sleep patterns and identify sleep onset rapid-eye-movement periods (SOREMPs).
Main Results:
- In both monozygotic twin pairs, only one twin presented with narcolepsy/cataplexy symptoms.
- Affected twins exhibited multiple SOREMPs and short mean sleep onset latencies on MSLT.
- Asymptomatic relatives, including one HLA DR2- individual, also showed abnormalities such as short sleep onset latencies or REM sleep during MSLT.
Conclusions:
- The findings strongly support a multifactorial pathogenetic model for narcolepsy, involving both genetic and environmental influences.
- Narcolepsy's etiology is complex, with genetic factors like HLA DR2 interacting with non-genetic elements to trigger the disease.