Screening for First-Degree Relatives of MS Patients
No routine screening is recommended for asymptomatic first-degree relatives of patients with multiple sclerosis. The available guidelines focus exclusively on diagnosis and monitoring of symptomatic individuals, not screening of at-risk family members 1, 2.
Why Screening Is Not Recommended
The diagnostic criteria for MS require at least one clinical event consistent with acute demyelination as the cornerstone for diagnosis 1. This means:
- MRI findings alone are insufficient for diagnosis, even if lesions appear consistent with MS 1, 2
- Diagnosis should only be pursued when a patient presents with subacute neurological symptoms such as unilateral optic neuritis, partial myelitis, sensory disturbances, or brainstem syndromes 2, 3
- The McDonald criteria apply best to individuals aged 10-59 years who are symptomatic, not asymptomatic at-risk individuals 1, 2
What First-Degree Relatives Should Know
While routine screening is not indicated, first-degree relatives should be educated about:
Key Warning Symptoms Requiring Prompt Evaluation
- Optic neuritis: Painful unilateral vision loss with loss of color vision developing over several days 2
- Partial myelitis: Sensory level, weakness, or bladder dysfunction 2
- Brainstem syndromes: Diplopia and internuclear ophthalmoplegia 2
- Sensory disturbances: Numbness or tingling in limbs 3, 4
Important Context About Familial MS
Research suggests that approximately 20% of MS cases have a family history, with first-degree relatives having increased risk 5. However, this does not justify screening because:
- Most individuals with a family history never develop MS 5
- Familial cases may present with slower onset compared to sporadic cases 5
- When familial MS does occur, it may have higher disability scores and more frequent exacerbations, but this reinforces the need for prompt evaluation of symptoms rather than screening 5
Clinical Approach When Symptoms Develop
If a first-degree relative develops concerning neurological symptoms, the diagnostic workup should include:
- MRI of the brain looking for periventricular, juxtacortical, infratentorial, and spinal cord lesions 2, 3
- CSF analysis for oligoclonal bands if diagnosis is uncertain 2, 3
- Visual evoked potentials if optic nerve involvement is suspected 2
- Application of the 2017 McDonald Criteria requiring dissemination in space and time 3, 4
Critical Pitfall to Avoid
Do not order screening MRIs in asymptomatic relatives. Finding incidental white matter lesions in an asymptomatic person creates diagnostic confusion and may lead to misdiagnosis, as many conditions can produce MRI findings that mimic MS 1, 2. The diagnosis requires clinical correlation with symptoms, not imaging alone 1.