Haemophilia A in a Female German Shepherd With Homozygosity for the FVIII p.C567Y Variant in Exon 11 of the F8 Gene

Description

Brenig and Pach reported in 2026 a rare case of haemophilia A in a female German Shepherd dog. The bleeding disorder stems from a fault in the F8 gene on the X chromosome, so females are usually only carriers. Mating a mildly affected male with a carrier can produce daughters carrying the fault on both copies. Their patient bled heavily from minor injuries from puppyhood, starting with swelling after microchip placement at three months.

Clotting tests showed a greatly prolonged clotting time with factor VIII activity at only about six percent of normal, while related factors were normal. Whole-genome sequencing found the same fault on both gene copies, changing one building block in a region vital to the factor's stability. The variant had been seen once before in an unrelated German Shepherd over a decade earlier. The authors stress full genetic workups in rare disease with odd inheritance.

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Source: https://europepmc.org/article/MED/PMC13291924