Lateral medullary syndrome in a boy with hereditary dysfibrinogenemia.

A 9-year-old boy presented with sudden onset of nausea, vomiting and unsteady gait after a bread-eating game, which possibly caused neck hyperextension. Neurological examination revealed hemisensory loss of pain and temperature sensation in the right trunk and limbs along with left Horner's syndrome, suggesting lateral medullary syndrome (LMS). Magnetic resonance (MR) imaging of the brain revealed infarction at the left lateral medulla. MR angiography showed no sign of arterial dissection and no occlusion or stenosis of the intracranial, basilar or vertebral arteries or their branches. No evidence of cardioemboli or systemic inflammation was apparent. Repeated blood examination revealed low activity of fibrinogen. Genetic testing confirmed the presence of hereditary dysfibrinogenemia with a mutation in the FGB gene (BßGly15Cys). This fibrinogen variant has previously been found in Japanese patients with atherosclerosis obliterans or no symptoms. Under conservative treatment without anticoagulation and aspirin, the patient made a good recovery within a few months. We presume that microthrombosis may have been deposited within the vertebral system as a result of extension and rotation of the neck during sports activity, with a contribution from hereditary dysfibrinogenemia.

Analysis of plasmin generation and clot lysis of plasma fibrinogen purified from a heterozygous dysfibrinogenemia, BbetaGly15Cys (Hamamatsu II).

We found a heterozygous dysfibrinogenemia caused by the substitution of BbetaGly15Cys and designated it fibrinogen Hamamatsu II (H-II). Although the propositus suffered an infarction of the medulla oblongata, other thrombotic risk factors, paradoxical cerebral infarction, and arterial dissection were not found. To determine whether the delayed lysis of fibrin clots or not in the context of the BbetaGly15Cys substitution, we examined the clot lysis and plasmin generation of propositus' fibrinogen. Fibrinogen was purified from the propositus' and normal control plasma by immunoaffinity chromatography and was used for the following experiments: sodium dodecyl sulfate-polyacrylamide gel electrophoresis, fibrin polymerization, scanning electron microscopic observation of fibrin clot and fibers, clot lysis, and tissue-type plasminogen activator-mediated plasminogen activation. The H-II plasma fibrinogen showed the presence of albumin-binding variant forms, a dimeric molecule of variant fibrinogen, and impairment of lateral aggregation during fibrin polymerization. The H-II fibrin clot showed lower density of bundles and thinner diameters of fibers than in the normal fibrin clot. In the clot lysis experiments with overlaid plasmin, H-II fibrin showed a similar lysis period and lysis rate to the normal control. Moreover, plasmin generation from a mixture of thrombin, tissue-type plasminogen activator, plasminogen, and H-II fibrinogen also showed a similar rate to normal fibrinogen. Although the propositus suffered an infarction, the present study did not observe delayed clot lysis, that is, the clot was not resistant to plasmin degradation. Therefore, we did not clarify an association between the BbetaGly15Cys dysfibrinogenemia and arterial thrombosis.