Prothrombin Greenville, Arg517→Gln, Identified in an Individual Heterozygous for Dysprothrombinemia

Abstract

A 64-year-old white male was referred for evaluation of prolonged prothrombin time (PT) and activated partial thromboplastin time (aPTT) obtained before elective surgery with initial PT and PTT results of 14.9 and 38.4 seconds, respectively, which corrected to normal in 1:1 mixes with normal plasma. Functional prothrombin assay indicated a level of 51% with thromboplastin as an activator. The prothrombin antigen was 102%. This discordance in the functional and immunologic prothrombin levels was evidence for dysprothrombinemia. Western blotting showed that thrombin was formed at a normal rate in diluted plasma consistent with a mutation within the thrombin portion of prothrombin. DNA was isolated from leukocytes and the thrombin exons were amplified by polymerase chain reaction, cloned, and sequenced. For exon 13, eight clones were sequenced with four clones showing a point mutation in the codon for Arg517, which would result in substitution by Gln. Arg517 is part of the Arg-Gly-Asp(RGD) sequence in thrombin and contributes to an ion cluster with aspartic acid residues 552 and 554. Mutation at this residue most probably distorts the structure of the Na+ binding site in thrombin. This is the first report indicating the critical role of Arg517 in the normal physiological interaction of thrombin with fibrinogen. This dysprothrombin is designated Prothrombin Greenville.

Phenotypic and genetic analysis of dysprothrombinemia due to a novel homozygous mutation

“…The prothrombin (factor II, FII) is a vitamin K-dependent zymogen, which was synthesized primarily in the liver, and composed of 579 amino acid residues. The FII molecule contains a γ-carboxyglutamic acid domain (Gla, 1-40), two kringle domains (41-271) and a catalytic serine protease domain (271-579) [1]. It is encoded by the gene F2, which was located on chromosome 11p11-q12, including 14 exons and 13 introns.…”

Prothrombin Saint‐Denis: a natural variant with a point mutation resulting in Asp to Glu substitution at position 552 in prothrombin

“…The same homozygous mutation E466 (146) A was associated with a severe prothrombin deficiency in two unrelated families (Miyata et al, 1992;Degen et al, 1995), with significant bleeding in one family (Degen et al, 1995) and not in the other (Bezeaud et al, 1988). Two other variants with a defect in the Na + binding site (Henriksen et al, 1998;Sun et al, 2001) are not associated with bleeding but have been detected only in heterozygotes. The proband described here is homozygous for the D552 (221) E mutation, with a severe defect in fibrinogen clotting but no bleeding.…”

Congenital prothrombin defects: they are not only associated with bleeding but also with thrombosis: a new classification is needed

“…Several dysprothrombinemias with mutations in sites of the protein upstream on downstream of the Arg596 site have been described but no association with thrombosis has ever been reported (Table 3). These dysprothrombinemias are prothrombin Salakta (Gln509Ala), prothrombin Greenville (Arg517Gln), prothrombin Perija (Gly548Ala), prothrombin Scranton (Lys599Thr) and others show mutation close to the Arg596 amino acid but apparently no venous thrombosis has ever been reported [12][13][14][15][16][17][24][25][26]. As far as we can tell the critical area seems to reside around Arg596, site of the mutation of the cases associated with a demonstrated occurrence of venous thrombosis.…”

“…This interesting observation remained silent for several years and the prothrombin defects were always considered to be responsible of a bleeding tendency. Several dysprothrombinemias were reported but no thrombosis event was ever mentioned [2,3,[12][13][14][15][16][17].…”