A Cluster of Amyotrophic Lateral Sclerosis

Abstract

Amyotrophic lateral sclerosis (ALS) is an uncommon disorder with a prevalence of four to six per 100,000 population. The age-adjusted incidence is 1.8 per 100,000 in white Americans. The epidemiology is poorly understood; minor sex and racial differences exist.¹ Reports by Hochberg and co-workers,² Kilnes and Hochberg,³ Sanders,⁴ and Tyler (written communication, April 28, 1980) have described clusters of a few unrelated persons in whom the disease developed at roughly the same time. We report the cases of three patients who lived in the same apartment building in Montreal and in whom ALS developed within an 18-month period. These three unrelated patients were all of Ashkenazi Jewish extraction and were aged between 57 and 63 years. The clinical features were typical of ALS. REPORT OF CASES Case 1.—In March 1978, a 63-year-old man who had a nine-month history of fasciculations on exertion and increasing weakness