Assessment of Early Evidence of Multiple Sclerosis in a Prospective Study of Asymptomatic High-Risk Family Members.

Importance: Subclinical inflammatory demyelination and neurodegeneration often precede symptom onset in multiple sclerosis (MS).

Objective: To investigate the prevalence of brain magnetic resonance imaging (MRI) and subclinical abnormalities among asymptomatic individuals at risk for MS.

Design, Setting, And Participants: The Genes and Environment in Multiple Sclerosis (GEMS) project is a prospective cohort study of first-degree relatives of people with MS.

Genes and Environment in Multiple Sclerosis project: A platform to investigate multiple sclerosis risk.

The Genes and Environment in Multiple Sclerosis project establishes a platform to investigate the events leading to multiple sclerosis (MS) in at-risk individuals. It has recruited 2,632 first-degree relatives from across the USA. Using an integrated genetic and environmental risk score, we identified subjects with twice the MS risk when compared to the average family member, and we report an initial incidence rate in these subjects that is 30 times greater than that of sporadic MS.