Dysfibrinogenemia-Potential Impact of Genotype on Thrombosis or Bleeding

The FGG c.952G>A variant causes congenital dysfibrinogenemia characterized by recurrent cerebral infarction: a case report

Background

Congenital dysfibrinogenemia (CD) is a rare hereditary coagulation disorder resulting from mutations in fibrinogen genes. CD primarily presents with bleeding symptoms, but it can also lead to thrombotic events, including ischemic stroke.

Case presentation

This report describes the case of a 52-year-old Chinese man who was admitted to the hospital twice due to recurrent cerebral infarction, characterized by sudden speech impairment and weakness in the right upper extremity. Brain MRI revealed multiple ischemic changes, predominantly in the left frontal and parietal lobes. Coagulation tests demonstrated reduced plasma fibrinogen (Clauss method), prolonged prothrombin time and thrombin time, and an elevated international normalized ratio. However, the ELISA assay indicated elevated levels of fibrinogen γ-chain protein. Despite a 2-month-old treatment regimen with aspirin, clopidogrel, and atorvastatin after the first hospitalization, the patient experienced a second ischemic stroke. Genetic analysis using whole-exome sequencing (WES) and Sanger sequencing identified a rare heterozygous missense variation, FGG c.952G>A (rs267606810), in both the stroke patient and his asymptomatic sister. Both individuals exhibited the same alterations in fibrinogen, characterized by reduced functional levels but increased antigenic protein. Subsequently, the patient was diagnosed with ischemic stroke associated with congenital dysfibrinogenemia.

Conclusion

This case report expands the clinical phenotype spectrum associated with FGG c.952G>A (rs267606810) and underscores the significance of considering CD as a potential etiology for unexplained ischemic stroke, particularly in patients with a family history of coagulation disorders.

Congenital fibrinogen disorders: Strengthening genotype-phenotype correlations through novel genetic diagnostic tools

Congenital fibrinogen disorders or CFDs are heterogenous, both in clinical manifestation and array of culprit molecular lesions. Correlations between phenotype and genotype remain poorly defined. This review examines the genetic landscape discovered to date for this rare condition. The question of a possible oligogenic model of inheritance influencing phenotypic heterogeneity is raised, with discussion of the benefits and challenges of sequencing technology used to enhance discovery in this space. Considerable work lies ahead in order to achieve diagnostic and prognostic precision and subsequently provide targeted management to this complex cohort of patients.

Congenital Afibrinogenemia and Hypofibrinogenemia: Laboratory and Genetic Testing in Rare Bleeding Disorders with Life-Threatening Clinical Manifestations and Challenging Management

Congenital fibrinogen disorders are rare pathologies of the hemostasis, comprising quantitative (afibrinogenemia, hypofibrinogenemia) and qualitative (dysfibrinogenemia and hypodysfibrinogenemia) disorders. The clinical phenotype is highly heterogeneous, being associated with bleeding, thrombosis, or absence of symptoms. Afibrinogenemia and hypofibrinogenemia are the consequence of mutations in the homozygous, heterozygous, or compound heterozygous state in one of three genes encoding the fibrinogen chains, which can affect the synthesis, assembly, intracellular processing, stability, or secretion of fibrinogen. In addition to standard coagulation tests depending on the formation of fibrin, diagnostics also includes global coagulation assays, which are effective in monitoring the management of replacement therapy. Genetic testing is a key point for confirming the clinical diagnosis. The identification of the precise genetic mutations of congenital fibrinogen disorders is of value to permit early testing of other at risk persons and better understand the correlation between clinical phenotype and genotype. Management of patients with afibrinogenemia is particularly challenging since there are no data from evidence-based medicine studies. Fibrinogen concentrate is used to treat bleeding, whereas for the treatment of thrombotic complications, administered low-molecular-weight heparin is most often. This review deals with updated information about afibrinogenemia and hypofibrinogenemia, contributing to the early diagnosis and effective treatment of these disorders.