To the Editor.—
Our foundation has been engaged in amyotrophic lateral sclerosis (ALS) research for more than 20 years, affording us an unusual opportunity to observe more than 1,000 patients experiencing all stages of ALS.The etiology of ALS is unknown; therefore, epidemiologic observations are difficult to accumulate.We saw a patient with definite ALS involvement who worked as a mail clerk in a small town (population, 1,200) post office. Three Caucasian men constituted the total mail service. All three of these mail clerks contracted ALS and died within ten years. None of these patients were related to each other, and each case appeared to be fulminating in character. These observations may be of interest or generally useful to the medical profession.