Kaufman et al. (2006) found a four-way interaction between maltreatment history, BDNF genotype, 5-HTTLPR genotype, and social supports, where social supports decreased depression scores for maltreated children who were carriers of the 5-HTTLPR s/s genotype and the BDNF Met-allele [32]. The gene discussed is BDNF; the disease is depressive symptom measurement.