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Identification and Three-dimensional Structural Analysis of Nine Novel Mutations in Patients with Prothrombin Deficiency

Journal: Thrombosis and Haemostasis
ISSN: 0340-6245
Issue: 2000: 84/6 (Dec) pp.935-1135
Pages: 989-997

Identification and Three-dimensional Structural Analysis of Nine Novel Mutations in Patients with Prothrombin Deficiency

Sepideh Akhavan (1) , Pier M. Mannucci (1) , Manijeh Lak (2) , Giacomo Mancuso (3) , Maria G. Mazzucconi (4) , Angiola Rocino (5) , P. Vincent Jenkins (6) , Stephen J. Perkins (7)
From (1) Angelo Bianchi Bonomi Hemophilia and Thrombosis Center and Fondazione Luigi Villa, IRCCS Maggiore Hospital and University of Milan, Italy; (2) Department of Hematology, Iman Khomeini Hospital, University of Tehran, Iran; (3) Hemophilia Center,

Summary

Prothrombin deficiency is an autosomal recessive disorder associated with a moderately severe bleeding tendency. In this study, 13 patients with prothrombin deficiency were screened for the presence of alterations in the prothrombin gene, and nine novel candidate mutations were identified. Of 11 patients with hypoprothrombinemia, ten are homozygous for five mutations and one patient is a compound heterozygote. The two patients with dysprothrombinemia are homozygous for two mutations. Eight of nine mutations are missense ones associated with single amino acid substitutions in the propeptide (Arg-1Gln, Arg-2Trp), the kringle-1 (Asp118Try) and kringle-2 (Arg220Cys) domains and the catalytic serine protease domain (Gly330Ser, Ser354Arg, Arg382His and Arg538Cys). The ninth mutation is an in-frame deletion of 3 bp that results in the omission of one amino acid (del Lys 301/302). The combination of these missense mutations with crystal structures for -thrombin and the prothrombin fragments 1 and 2 resulted in new insight into the function of -thrombin. The hypoprothrombinemia mutations were inferred to affect either the cleavage of the propeptide from the Gla domain, the stability of the kringle-1 and –2 domains, or the close association of the A and B chains of the serine protease domain. The dysprothrombinemia mutations were inferred to directly affect catalytic function through their location at the active site crevice or exosite 1 within the serine protease domain.