Thromb Haemost 2007; 97(04): 542-545
DOI: 10.1160/TH06-09-0532
Blood Coagulation, Fibrinolysis and Cellular Haemostasis
Schattauer GmbH

Analysis of the novel factor X gene mutation Glu51Lys in two families with factor X-Riyadh anomaly

Akram Al-Hilali
1   Haematology Department, Laboratories, King Fahad Armed Forces Hospital, Jeddah- Saudi Arabia
,
Karin Wulff
2   Institut für Humangenetik, Ernst-Moritz Arndt-University Klinikum Greifswald, Greifswald, Germany
,
Hikmat Abdel-Razeq
3   Hematology-Oncology Unit, Section of Hematology and Medical Oncology, Department of Medicine, King Hussein Cancer Center, Amman, Jordan
,
Khalida Abu Saud
1   Haematology Department, Laboratories, King Fahad Armed Forces Hospital, Jeddah- Saudi Arabia
,
Fateh Al-Gaili
1   Haematology Department, Laboratories, King Fahad Armed Forces Hospital, Jeddah- Saudi Arabia
,
Falko H. Herrmann
2   Institut für Humangenetik, Ernst-Moritz Arndt-University Klinikum Greifswald, Greifswald, Germany
› Author Affiliations
Further Information

Publication History

Received 21 September 2006

Accepted after resubmission 23 January 2007

Publication Date:
24 November 2017 (online)

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Summary

Two families with 'factor X(FX)-Riyadh' have been identified (one of them related to the originally reported family). Affected members of both families exhibit prolongation in prothrombin time (PT) with normal partial thromboplastin time (PTT) and low assay levels of FX, when measured by PT-based assay. They do not have clinical bleeding diathesis, regardless of the PT prolongation. FX genes of the affected family members were analyzed by sequence analysis. A novel missense mutation in exon 4 of the FX gene, which causes the Glu51Lys substitution in the first epidermal growth factor-like domain of FX was found. The Glu51Lys mutation represents a type II mutation with low FX coagulant activity in the extrinsic pathway and normal FX antigen levels. This mutation may result in disruption of the predicted H-bonding between residue Glu51 of FX and the Asn199 residue of the tissue factor (TF) in the FX/TF/factorVIIa ternary complex, producing the phenotype 'FX deficiency Riyadh', with prolonged PT and normal PTT.