What are the genetic changes related to protein C deficiency ?
Protein C deficiency is caused by mutations in the PROC gene. This gene provides instructions for making protein C, which is found in the bloodstream and is important for controlling blood clotting. Protein C blocks the activity of (inactivates) certain proteins that promote blood clotting.  Most of the mutations that cause protein C deficiency change single protein building blocks (amino acids) in protein C, which disrupts its ability to control blood clotting. Individuals with this condition do not have enough functional protein C to inactivate clotting proteins, which results in the increased risk of developing abnormal blood clots. Protein C deficiency can be divided into type I and type II based on how mutations in the PROC gene affect protein C. Type I is caused by PROC gene mutations that result in reduced levels of protein C, while type II is caused by PROC gene mutations that result in the production of an altered protein C with reduced activity. Both types of mutations can be associated with mild or severe protein C deficiency; the severity is determined by the number of PROC gene mutations an individual has.