Does early-onset MS carry higher risk for family members?

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Takeaway

  • 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.

Key results

  • 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.

Study design

  • 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.

Limitations

  • 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.