GMNC and Alzheimer disease: In line with mode-cluster 16 being dominated by the volumetric measure of CSF (cerebro-spinal fluid, which fills the ventricles), mode 262 (fornix MD) is associated with SNP rs150434736 (on chromosome 3, only 17kbp from the 3:190657741_AGT_A/rs147817028 peak in mode-cluster 16), near gene GMNC; this has been found to be linked to Alzheimer’s disease endophenotypes (in particular ptau 181 in CSF) (Cruchaga et al., 2013; Deming et al., 2017).