Protein C

The PROC gene encodes a protein which plays an important role in taming blood coagulation, so inactivating mutations bring about a higher risk of intravascular coagulation, increased risk of thrombosis. Protein C deficiency is inherited either autosomal dominant or recessive.

Epidemiology

The prevalence of protein C deficiency is 0,2-0,4%. This portion is higher, when patients with venous thrombosis are preselected an goes up to 2 to 13%.

Gene Structure

The gene is abreviated PROC. Its locus is on chromosom 2 (2q13-q14). Size is about 11kb. I consists of 9 exons but only 8 of them are translated.

Phenotype

Homozygous carrier of this mutation are extremely rare. They can be found when a newborn child suffers from some thromboembolic diseases. Heterozygous carriers develop venous Thrombosis. This occurs in 80% before age of 40. Most often the first such event occurs during pregnancy. Necrosi due to therapy with oral anticoagulants are most often in protein C deficiency. Sekundary protein C deficiencies have to be excluded.

Pathology

The protein product is a vitamin K dependent proteinase. When activated this enzyme (APC) inactivates the active coagulation factors Va and VIIIa and in the same time it increases fibrinolytic activity. Cofactor for these processes is protein S.

Test Strategy

Patient with biochemical evidence of Protein C deficiency when a secondary reason is excluded. Family screening if a family member is a carrier.

Interpretation

The risk of venous thrombosis is elevated for about 7,3 in carriers of protein C mutations.

Genetests:

Related Diseases:

Autosomal dominant protein C deficiency
	PROC

Autosomal recessive protein C deficiency
	PROC

References:

1.	Foster DC et al. (1985) The nucleotide sequence of the gene for human protein C.

2.	None (1998) The anticoagulant potential of the protein C system in hereditary and acquired thrombophilia: pathomechanisms and new tools for assessing its clinical relevance.

3.	NCBI article NCBI 5624

4.	OMIM.ORG article Omim 612283

5.	Orphanet article Orphanet ID 118030

6.	Wikipedia article Wikipedia EN (Protein_C)