Flow diagram depicting the ascertainment of GENEVA cases. Solid boxes or lines represent cases who advanced past each step shown. Small-dashed boxes or lines represent cases who were excluded after each step shown, but who were incorporated into the analysis via inverse probability weights (see Section 2.3 and Supplementary data, p. S6, for more details). Reasons cases were ineligible for GENEVA included dementia (n = 9), diagnosis change (n = 2), withdrawal from the Registry DNA bank (n = 3), or interview infeasibility (n = 11). Abbreviations: ALS, amyotrophic lateral sclerosis; GENEVA, Genes and Environmental Exposures in Veterans with Amyotrophic Lateral Sclerosis study; PLS, primary lateral sclerosis.