Acquired Dysfibrinogenemia Caused by Autoantibody Inhibiting Fibrin Polymerization in a Patient with MELAS Syndrome and Bleeding Tendency.

We present a case of acquired dysfibrinogenemia caused by an autoantibody that inhibited fibrin polymerization in a patient previously diagnosed with MELAS (mitochondrial myopathy, encephalopathy, lactic acidosis, stroke-like episodes). The patient showed prolonged PT, aPTT, and thrombin time. There was no factor deficiency but fibrinogen antigen and activity were decreased. ELISA for detection of fibrinogen antibodies were performed and IgG purified from the patient's plasma bound to fibrinogen more strongly than did control IgG, indicating the presence of a fibrinogen-specific antibody. Thrombin-mediated fibrin polymerization was severely impaired in the patient, although thrombin-induced fibrinopeptide A release was normal. Scanning electron microscopy was used to investigate the structure of fibrin clots and revealed many pores on the surface of patient's fibrin clots. Since MELAS is often associated with autoimmune disorders, a work-up for the presence of anti-fibrinogen antibody is necessary when bleeding tendency occurs in MELAS patients along with prolonged thrombin time.