title: Fibrinogen Chapel Hill: hypodysfibrinogenemia with a tertiary polymerization defect.
abstract: A patient with a functionally defective fibrinogen (fibrinogen Chapel Hill) has been investigated. Fibrinogen Chapel Hill is characterized by hypofibrinogenemia, with a plasma concentration about one third of normal, as measured both functionally and immunochemically. Fibrinogen survival is normal; so also is fibrinopeptide release. A polymerization defect in this fibrinogen results in the delay of fibrin fibrils in solution to form a normal three-dimensional gel. This defect is not associated with end-to-end aggregation or with lateral associations in solution. Delayed gelation results from an abnormality in a tertiary contact site involved in network branching, which is associated with the hydrophilic, carboxy-terminal segment of the alpha chain. Fibrinogen Chapel Hill exhibits two additional abnormal responses, which are also associated with the same region. The early plasmin cleavages of fibrinogen and fragment X are delayed, and there is a concomitant delay in the appearance of fragments Y, D, and E. This fibrinogen also has an unusual sensitivity to Ancrod proteolysis, whereby Ancrod cleaves a large carboxy-terminal segment of the alpha chain more rapidly than in normal fibrinogen. The abnormalities in fibrinogen Chapel Hill can be explained by a structural abnormality which is functionally related to an alpha chain associated polymerization domain.
mesh_terms: D000328:Adult; D000347:Afibrinogenemia / Q000235:genetics*; D000721:Ancrod / Q000378:metabolism; D001778:Blood Coagulation Disorders / Q000235:genetics*; D000013:Congenital Abnormalities; D004586:Electrophoresis; D005260:Female; D005340:Fibrinogen / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism; D006801:Humans
chemical_list: D005340:Fibrinogen; D000721:Ancrod