- First- and second-degree relatives of people with multiple sclerosis (MS) have a similarly increased risk for MS themselves, regardless of whether the affected person’s MS began early or late in life.
Why this matters
- Certain genetics are associated with timing of MS onset.
- Young age at onset may indicate higher genetic risk.
- Risk for first-degree relatives by timing of MS onset in the affected family member:
- Early-onset MS: OR, 10.86 (95% CI, 6.87-17.17);
- Late-onset MS: OR, 8.08 (95% CI, 6.12-10.67).
- Risk for second-degree relatives by timing of MS onset in the affected family member:
- Early-onset MS: OR, 3.83 (95% CI, 2.48-5.90);
- Late-onset MS: OR, 2.86 (95% CI, 1.87-4.39).
- Findings similar after adjustment for sex and birth era.
- Swedish population-based nested case-control study using registry data.
- 629 early-onset MS cases (first symptom
- Main outcome: MS risk in first-degree relatives.
- Funding: None.
- Potential lack of statistical power.
- Possibly inaccurate recall of symptom onset.
- Calendar year of birth differed between early-, late-onset groups.
- Data on MS phenotype unavailable.
- Unclear generalizability.