Here’s how PIK3CA mutations can cause these conditions
The PIK3CA gene gives instructions for the production of a protein called PI3K, or phosphoinositide 3-kinase. This PI3K protein is involved in the life cycle of the cell and making sure cells grow, develop, live, and die in the right way. When the PIK3CA gene is mutated, the instructions that the gene gives for making the PI3K protein are damaged. The PI3K protein does not work the way it should, causing cells to grow and divide abnormally, which results in the features of these PROS conditions.
The mutation first occurs during embryo development, or the early stages of fetal growth. This means that it is not passed down from parents to children.
The PIK3CA mutation is present at various levels in different cells and does not affect all cells in the body. As a result, PROS symptoms may occur only in certain parts of the body and affect those body parts in different amounts. Your doctor may call this “mosaicism.”