PPP2R3A and dyslexia: After adjusting for head size as a covariate, the brain-wide association maps remained similar for most of these 35 variants, although the PPP2R3A dyslexia-disposing variant was now associated with higher volumes in the cerebellum and midbrain rather than widespread regional volume reductions, and the association with the BCL11B variant extended to the thalamus (Fig. 3 and data S1).