Amyotrophic Lateral Sclerosis and Multiple Sclerosis: More Evidence Suggesting a Link
Objectives Previous reports of the concurrence of multiple sclerosis (MS) and amyotrophic lateral sclerosis (ALS) in the same patients suggest shared pathogenesis, with the C9orf72 mutation as a possible shared genetic link. Methods: Symptoms, neuroimaging, and laboratory data were summarized for patients with ALS and MS within our ALS registry. Using age adjusted MS prevalence rates, we calculated the expected co-occurrence using the binomial test. Results: Clinical and demographic features of the five patients (four female, one male) with ALS and MS are described. Because ALS more frequently occurs in men, observing 4/5 female patients with concurrent ALS/MS showed a borderline expectation difference (P=0.073). The observed co-occurrence of ALS and MS was 5X times higher than the expected frequency of 0.98 (P <0.004). Four patients were found negative for C9orf72. Discussion: Our results suggest a non-random association between MS and ALS, although shared genetic etiology was not found.