The clinical heterogeneity associated with progression to disability remains one of the mysteries surrounding multiple sclerosis (MS) and can be a source of consternation to patients and physicians alike. Patients who appear neurologically comparable at diagnosis often have widely divergent disease courses: some progress rapidly and require assistance to ambulate within a few years; others experience few relapses and remain almost neurologically intact for decades. Many have hypothesized that the phenotypic variability of MS stems from underlying genetic differences between patients.
Longbrake EE, Hafler DA. Linking Genotype to Clinical Phenotype in Multiple SclerosisIn Search of the Holy Grail. JAMA Neurol. 2016;73(7):777-778. doi:10.1001/jamaneurol.2016.1227