AKT1 and Proteus syndrome: As an example, the protein kinase AKT1 with somatic mutations are correlated with Proteus syndrome, whereas mosaicism for post-zygotic mutations in genes for three essential components of the phosphatidylinositol 3-kinase (PI3K)–AKT signaling pathway that increase signaling can trigger a variety of related megalencephaly syndromes (Poduri et al., 2013).