Venous thromboembolism associated with protein S deficiency due to Arg451* mutation in PROS1 gene: a case report and a literature review.

Protein S (PS) is a vitaminK-dependent glycoproteinwhich plays an important role in the regulation of blood coagulation. PS deficiency has been found in 1.5-7% of thrombophilic patients. Here, we report the first Polish case with PS deficiency caused by the p.Arg451* in the PROS1 gene detected in a 21-year-old man with trauma-induced venous thromboembolism. To our knowledge, we provided the review of all the available data on this mutation (a total of 56 cases). The proband, his mother and his sister were screened for thrombophilia. To elucidate genetic background of PS deficiency, all PROS1 genes were subjected to direct sequencing. The free PS levels were 35% in the proband, 21% in the proband's mother and 28% in the proband's sister and their PS total levels were 37.1, 47.5 and 55.1%, respectively. Type I PS deficiency was diagnosed. In all patients, genetic analysis revealed the presence of heterozygous nonsense mutation (c.1351C>T; p.Arg451*) located in exon 12 of PROS1 gene. This mutation interrupts the reading frame by premature termination codon at position 451 and may lead to the production of truncated protein. The present case combined with the review of the literature suggests that p.Arg451* in the PROS1 gene mainly leads to clinically evident thrombosis following trauma, surgery or serious comorbidities especially malignancy.