In hemophilia, which of the following is raised: September 2007

Ans. D: aPTT Hemophilia A is a recessive X-linked genetic disorder involving a lack of functional clotting Factor VIII and represents 80% of haemophilia cases. Hemophilia B is a recessive X-linked genetic disorder involving a lack of functional clotting Factor IX. It comprises approximately 20% of haemophilia cases. Haemophilia C is an autosomal genetic disorder (i.e. not X-linked) involving a lack of functional clotting Factor XI. Haemophilia C is not completely recessive: heterozygous individuals also show increased bleeding Prolonged APTT may indicate: Use of heparin (or contamination of the sample) Antiphospholipid antibody (especially lupus anticoagulant, which paradoxically increases propensity to thrombosis) Coagulation factor deficiency (e.g. hemophilia) Shoening of the PTT has little clinical relevance. Normal PTT times require the presence of the following coagulation factors: I, II, III, IV, V, VI, VIII, IX, X, XI, and XII. Notably, deficiencies in factors VII or XIII will not be detected with the PTT test.