In concordance with previous studies, a paraneoplastic etiology was established in most of the cohort.1,2,22 However, we identified a substantial proportion of patients without identifiable cancer after 2 years of follow-up, supporting prior findings of isolated reports that suggested the existence of an ‘idiopathic’ form of Ma2-Abs autoimmunity.13,16,17,24. This evidence concerns the gene PNMA2 and cancer.