In mouse models of genetic disorders that result in dendritic abnormalities such as Rett syndrome, a decrease in the soma size of hippocampal neurons was observed (Rangasamy et al., 2016), while loss of function mutations in the tuberous sclerosis complex (TSC), a negative regulator of the mTOR/Akt pathway, increase the soma size of hippocampal pyramidal neurons but decrease the density of dendritic spines causing alterations in glutamatergic transmission (Tavazoie et al., 2005). The gene discussed is MTOR; the disease is hereditary disease.