title: Antithrombin III deficiency in Indian patients with deep vein thrombosis: identification of first India based AT variants including a novel point mutation (T280A) that leads to aggregation.
abstract: Antithrombin III (AT) is the main inhibitor of blood coagulation proteases like thrombin and factor Xa. In this study we report the identification and characterization of several variants of AT for the first time in Indian population. We screened 1950 deep vein thrombosis (DVT) patients for AT activity and antigen levels. DNA sequencing was further carried out in patients with low AT activity and/or antigen levels to identify variations in the AT gene. Two families, one with type I and the other with type II AT deficiency were identified. Three members of family I showed an increase in the coagulation rates and recurrent thrombosis in this family was solely attributed to the rs2227589 polymorphism. Four members of family II spanning two generations had normal antigen levels and decreased AT activity. A novel single nucleotide insertion, g.13362_13363insA in this family in addition to g.2603T>C (p.R47C) mutation were identified. AT purified from patient's plasma on hi-trap heparin column showed a marked decrease in heparin affinity and thrombin inhibition rates. Western blot analysis showed the presence of aggregated AT. We also report a novel point mutation at position g.7549 A>G (p.T280A), that is highly conserved in serpin family. Variant protein isolated from patient plasma indicated loss of regulatory function due to in-vivo polymerization. In conclusion this is the first report of AT mutations in SERPINC1 gene in Indo-Aryan population where a novel point mutation p.T280A and a novel single nucleotide insertion g.13362_13363insA are reported in addition to known variants like p.R47C, p.C4-X and polymorphisms of rs2227598, PstI and DdeI.
authors: Protein Conformation and Enzymology lab, Department of Biosciences, Jamia Millia Islamia, New Delhi, India.
authors: Teena
authors: T
authors: Bhakuni
authors: Department of Haematology, All India Institute of Medical Sciences, New Delhi, India.
authors: Amit
authors: A
authors: Sharma
authors: Protein Conformation and Enzymology lab, Department of Biosciences, Jamia Millia Islamia, New Delhi, India.
authors: Qudsia
authors: Q
authors: Rashid
authors: Protein Conformation and Enzymology lab, Department of Biosciences, Jamia Millia Islamia, New Delhi, India.
authors: Charu
authors: C
authors: Kapil
authors: Department of Haematology, All India Institute of Medical Sciences, New Delhi, India.
authors: Renu
authors: R
authors: Saxena
authors: Department of Haematology, All India Institute of Medical Sciences, New Delhi, India.
authors: Manoranjan
authors: M
authors: Mahapatra
authors: Protein Conformation and Enzymology lab, Department of Biosciences, Jamia Millia Islamia, New Delhi, India.
authors: Mohamad Aman
authors: MA
authors: Jairajpuri
mesh_terms: D000595:Amino Acid Sequence; D000990:Antithrombin III / Q000737:chemistry / Q000235:genetics*; D020152:Antithrombin III Deficiency / Q000150:complications* / Q000235:genetics*; D001483:Base Sequence; D003198:Computer Simulation; D005190:Family; D020022:Genetic Predisposition to Disease; D006579:Heterozygote; D006801:Humans; D007194:India; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010641:Phenotype; D017354:Point Mutation / Q000235:genetics*; D020641:Polymorphism, Single Nucleotide / Q000235:genetics; D066329:Protein Aggregates; D017422:Sequence Analysis, DNA; D020246:Venous Thrombosis / Q000150:complications* / Q000175:diagnosis / Q000235:genetics
chemical_list: D066329:Protein Aggregates; D000990:Antithrombin III