Indeed, we recently reported for the same CARDS participants, that age-related reductions in fornix MPF and kf fully mediated age-related decline in hippocampal tissue but not vice versa, suggesting that fornix glia-related damage due to ageing and obesity, may cause hippocampal damage (Metzler-Baddeley et al., 2019). The gene discussed is AFMID; the disease is obesity due to melanocortin 4 receptor deficiency.