TPO and autoimmune thyroid disease: Our findings of borderline (non-) significant differences in the follow-up of both cohorts are congruent with the mixture of positive and negative reports (Bartalena et al. 1990; Kupka et al. 2002; Radhakrishnan et al. 2013; Haggerty et al. 1997; Cobo et al. 2015; Vonk et al. 2007; Oomen et al. 1996) on a genetic association of BD and thyroid autoimmunity and our inability to detect a higher prevalence of TPO-Abs in the bipolar parent of the DBO study.