Fig. 2: Manhattan plot and spatial mapping of the associations between T2* in the putamen and four SNPs.

a, The Manhattan plot relates to the original GWAS for the IDP T2* in the bilateral putamen. The lower grey line indicates the –log₁₀(P value) threshold of 7.5 and the upper line the threshold of 11 (see main text). b, The spatial maps show that the four SNPs (one per row) most strongly associated with T2* in the putamen have distinct voxelwise patterns of effect across the whole brain: the effect of rs4428180 (TF) is found in the dorsal putamen and body of the caudate nucleus, but also in the right subthalamic nucleus and substantia nigra, red nucleus, lateral geniculate nucleus of the thalamus and dentate nucleus; rs144861591 (HFE) in the dorsal striatum, subthalamic nucleus, dentate nucleus and Crus I/II of the cerebellum; rs10430578 (SLC39A12) in the whole dorsal striatum and pallidum; and rs668799 (COASY) in the whole dorsal striatum, subgenual cingulate cortex and entorhinal cortex. The standard MNI152 T1 image is used as background for the spatial maps (left is right). All group difference images (colour overlays) are thresholded at a T2* difference of 0.6 ms. These voxelwise SNP association maps were calculated from the discovery sample of 8,428 subjects (see main text).