DEFICIENCY OF FACTOR XII (Hageman factor)

• Biochemical aspects:
  Factor XII is a single-chain beta-globulin with a MW of 80,000. Activated factor XII cleaves prekallikrein, factor XI, and factor VII proteolytically, converting them to their active forms.
• Pathological Basis:
  • Mode of inheritance: autosomal recessive.
  • Acquired deficiency is seen in patients with nephrotic syndrome. The pathological basis of this acquired deficiency has not been established since urinary loss of factor XII alone may not account for the reduced plasma activity of this factor.
• Treatment:
  • No treatment necessary for hereditary type.
  • Management of nephrotic syndrome in acquired type.