Methods for treating and/or limiting development of diabetes in a subject with amyotrophic lateral sclerosis (ALS) by inhibiting IgG-mediated activation of voltage-gated calcium channels (VGCCs) in cells of the subject, by one or more of removing IgG from blood of the subject, blocking IgG from activating VGCCs in the subject； or blocking VGCCs in the subject are described, as are methods for identifying ALS patients at risk of developing diabetes.
