The term protein C deficiency refers to a congenital or acquired coagulation disorder in which coagulation is increased due to a lack of control on the part of protein C and sometimes proceeds unchecked. This is accompanied by an increased risk of blood clots forming in the smallest blood vessels (capillaries), which can lead to oxygen deficiency and tissue death. The consequences range from redness and skin necrosis to multiorgan failure, which is fatal if left untreated.
Basics
The ability of human blood to clot in case of injury or trauma is a vital property. It prevents internal and external bleeding and, if necessary, runs as a complicated cascade of 13 so-called coagulation factors. However, in order to prevent the blood from coagulating unintentionally in uninjured areas, coagulation is subject to precise controls at various points.
One of them contains the protein C. Protein C is a protein produced in the liver and must be present in the blood in a certain amount. Uninjured vascular areas activate protein C to form activated protein C (aPC), which in turn binds to another protein, protein S, and together with it inhibits coagulation factors 5 and 13. Due to this inhibition, the cascade cannot run off and an undisturbed blood flow in the intact vessel is guaranteed. This system is the body’s most important regulatory mechanism for inhibiting coagulation. If this protein C is present in insufficient concentration, the patient suffers from protein C deficiency.
Causes
As mentioned above, protein C deficiency can be differentiated between congenital and acquired causes. Congenital severe protein C deficiency is fortunately an extremely rare disease with a statistical incidence in the population of approx. 1:30,000.
Responsible for protein C deficiency is a mutation in the protein C gene (PROC gene) on the DNA. This mutation can also be inherited by children. This increases the risk for children of sick parents to also suffer from protein C deficiency.
A type 1 is distinguished from a type 2 on the basis of the concentration in the blood and the ability to perform its tasks. A type 1 protein C deficiency is characterized by the fact that the protein is present in the blood in a reduced form and at the same time in a significantly reduced amount (true protein C deficiency). In contrast, a patient with type 2 protein C deficiency has almost sufficient protein, but cannot fulfil its task (protein C defect).
Both types can cause massive symptoms and can even be fatal. On the other hand, there are the acquired causes that can lead to a protein C deficiency. Other diseases or health situations are primarily responsible for the deficiency, which then occurs secondarily and can usually be eliminated by treating the underlying disease.
Basically, a reduced production or increased consumption of protein C can be responsible. Typical acquired causes are diseases of the liver, the place of formation of protein C, such as liver cirrhosis, liver fibrosis or a viral inflammation of the liver (hepatitis). Tumors that destroy liver tissue can also lead to protein C deficiency in late stages.
In addition, treatment with anticoagulants such as Marcumar causes a protein C deficiency, which is why it is essential to give heparin for a few days in an overlapping manner when starting treatment with Marcumar. Vitamin K is necessary for the formation of protein C. Consequently, a vitamin K deficiency due to malnutrition or undernourishment also leads to an acquired protein C deficiency. Increased consumption, which leads to a lack of protein C, is particularly common in sepsis. Sepsis is a severe clinical picture in which the blood and thus the body is flooded with bacterial pathogens.
