Hereditary coagulopathy characterized by the practically complete absence of plasma fibrinogen. It produces a severe bleeding disorder with prolonged bleeding, spontaneous haemorrhages and, in puppies, umbilical haemorrhage. It is the canine equivalent of human congenital afibrinogenemia and in the dog it has been associated with variants in the fibrinogen chain genes (FGA, FGB, FGG). In the Miniature Wirehaired Dachshund a frameshift variant in FGA has been identified.

Limited data regarding population frequencies. The molecular form is characterized in the Miniature Wirehaired Dachshund (four cases in one family). The disease is very rare overall; isolated cases have been described in other breeds.

- Umbilical bleeding at birth or in the first days
- Extensive spontaneous haematomas
- Haemorrhages after minimal trauma
- Undetectable thrombin time and undetectable fibrinogen
- Markedly prolonged prothrombin and partial thromboplastin times

Congenital fibrinogen disorders are very rare in the dog and have been reported in several breeds (Bernese Mountain Dog, Bichon Frise, Cocker Spaniel, Collie, Lhasa Apso, Vizsla, Saint Bernard and Dachshund). Mischke and colleagues (2021) studied four Miniature Wirehaired Dachshunds with afibrinogenemia: by homozygosity mapping and association study they identified a frameshift variant in FGA (c.1665delT, p.Ile555Metfs*33; rs1152388481) that co-segregated perfectly with the disease and was validated in 393 Dachshunds and 33 other breeds. The variant had spread in the breed through carriers before the first cases were detected.

- Genotype breeding animals with the specific FGA test when available before mating
- Do not repeat the parental cross if a case is confirmed
- Do not cross two carriers: 25 % risk of affected homozygotes
- Communicate the status to the referring veterinarian before any scheduled surgery

Distinguish from von Willebrand disease, haemophilia A/B and consumption coagulopathies (DIC, massive haemorrhages). Diagnosis is based on undetectable functional fibrinogen and correction with fresh frozen plasma or cryoprecipitate. In the Miniature Wirehaired Dachshund the molecular basis is characterized (FGA c.1665delT), which allows breeding advice by genetic testing; in other breeds the advice may depend on the pedigree.

1. Mischke R et al. (2021) An FGA frameshift variant associated with afibrinogenemia in Dachshunds. Genes (Basel). PMID: 34356081
2. OMIA:002382-9615 Afibrinogenaemia, FGA-related. https://omia.org/OMIA002382/9615/
3. Genética de las afibrinogenemias humanas: FGA, FGB, FGG (correlato molecular).