<prompt> Which among the following factors level is not altered in vit K deficiency?ProthrombinFactor VIIIFactor VIIFactor X  <response>: Ans b: Factor VIII Ref: Harrison p.367, 728-730Coagulation factors II, VII, IX, X and protein C, S and Z are dependent on Vit K for post translational modification. Vit K also for bone protein osteocalcin and vascular smooth muscle protein- matrix glaproteinFew more points: Gamma carboxy glutamic acid residues in the Vit k dependent factors will help in their critical action including calcium and phospholipid binding Mutations in Vit k epoxide reductase complex 1 VKORC1 andgene encoding gamma glutamyl carboxylaseGGCX result in defect free enzyme and there in Vit K dependent factors with decreased activity. Causes mild to severe bleeding episodes from birth Prolongation of PT is the most common and earliest finding in Vit K deficiency. Factor V11 has the shortest tl2, so PT prolonged much before changes in aPTT 