Afibrinogenemia, congenital / Dysfibrinogenemia / Hypofibrinogenemia
Definition
The FGB gene encodes the beta chain of fibrinogen, the protein that is converted into fibrin strands in the final step of coagulation and forms the structural scaffold of the clot. This term covers three different disorders: in congenital afibrinogenemia, there is almost no measurable fibrinogen in the circulation; in hypofibrinogenemia, the amount is reduced but not entirely absent; in dysfibrinogenemia, the amount is normal but the protein produced is functionally defective, most patients are asymptomatic, some may have bleeding, and some may show a paradoxical tendency to thrombosis.
Gene/region examined
FGB - Whole Gene
Method
Sequence analysis
Accepted sample types
EDTA blood, AF, CVS
Inheritance
Afibrinogenemia and hypofibrinogenemia are inherited in an autosomal recessive manner; dysfibrinogenemia is mostly inherited in an autosomal dominant manner, and a single mutant copy can produce the clinical picture.