Proteus syndrome

Proteus syndrome is caused by mutations in the AKT1 gene. These mutations are not inherited from a parent, but arise randomly in one cell during the early stages of development before birth. As cells continue to grow and divide, some cells will have the mutation and others will not. Therefore, people with Proteus syndrome have an altered AKT1 gene only in some of their cells. This mixture of cells with and without a genetic mutation is known as mosaicism.^[1] The AKT1 gene codes a protein that helps regulate cell growth and division (proliferation) and cell death. A mutation in this gene disrupts a cell's ability to regulate its own growth, allowing it to grow and divide abnormally. The mutated gene makes an abnormal protein. The mutation in the AKT1 gene is known as “c. 49G>A, p.Glu17Lys,” and it is a type of an “activating mutation.”  This means that the AKT1 gene has a “spelling error” that causes an abnormally active protein to be made in the body. This active protein is thought to increase rates of cell growth and may prevent cells from dying off when they naturally would. Increased cell proliferation in various tissues and organs leads to the abnormal growth characteristics and to an increased risk to develop tumors.^[1][2][3]