The reason that AIDS orphans have smaller hippocampi may be that the hippocampus contains a high density of glucocorticoid receptors, so it appears particularly susceptible to the deleterious effect of chronic stress created by early adversity [28, 38–40] associated with the AIDS diagnosis and institutional rearing, such as stigma and poverty [7, 8, 11]. Here, NR3C1 is linked to AIDS.