Genetic Defects in 10 Index Cases of Inherited Vitamin K Dependent Clotting Factors Deficiency

Introduction: Vitamin K dependent factors i.e II, VII, IX and X plays an important role in the clotting mechanisms of the human body. Deficiency or defect in any of these factors, Vitamin K or Gamma glutamyl Carboxylase (GC) and Vitamin K Epoxide Reductase (VKOR) involved in the metabolism of these factors will compromise the clotting mechanisms and can lead to the bleeding disorder. 28 rare single mutations in VKORC1 coding sequence have been reported so far.

Objective: To investigate the biochemical, haemostatic and molecular basis of the Vitamin K dependent factor deficiency in Pakistani subjects.

Setting: NIBD &BMT, University of Bonn and Children hospital.

Method: For this purpose 10 subjects, 9 males and 1 female with age ranging from 7 months to 13years were included from selected region of Pakistan who had a history of bleeding disorder and low levels of all the Vitamin K dependent clotting factors. BT, PT, APTT, Factor II, VII, IX, X,Platelet count and fasted serum bile acids were analysed for exclusion of thromobocytopenia which cause of bleeding and bile acid for cholestatic liver disease respectively. DNA sequencing was done for the GCCX and VKOR encoding gene i.e. GCCX-1 and VKORC-1 respectively to understand the etiology at molecular level.

Results: Platelet counts of all the subjects were normal only in one case it was mild low 100x10³/ul. Mean± S.E.M value of platelet was 440x10³ ± 67. Factor II, VII, IX and X mean levels were 12.7%, 6.9%, 11.2%, 7.1% respectively. Out of ten subjects mean bile acid levels were increased in 3 patients (20 µmole/l) while 3 had low levels (1.2 µmole/l). 3 novel mutations identified in GCCX-1 gene in those patients who had normal levels of bile acids.

Conclusion: Out of ten only in three patients novel mutations were identified in GCCX-1 while other 6 patients had abnormal levels of bile acid may be a cause of vitamin K clotting factors deficiency.Better strategies for the diagnosis of vitamin K deficiency are needed.