Phenotypical variability in congenital FVII deficiency follows the ISTH-SSC severity classification guidelines: a review with illustrative examples from the clinic

Shilpa Jain,1,2 Jennifer Donkin,3 Mary-Jane Frey,4 Skye Peltier,5 Sriya Gunawardena,6 David L Cooper6 1Hemophilia Center of Western New York, Buffalo, NY, USA; 2Department of Pediatrics, Division of Pediatric Hematology-Oncology, John R. Oishei Children’s Hospital, University of Buffalo, Buffalo, NY, USA; 3Hemostasis and Thrombosis Center, Children’s Hospital Los Angeles, Los Angeles, CA, USA; 4Children’s Hospital of Michigan, Detroit, MI, USA; 5Center for Bleeding and Clotting Disorders, University of Minnesota, Minneapolis, MN, USA; 6Clinical Development, Medical and Regulatory Affairs, Novo Nordisk Inc., Plainsboro, NJ, USA Background: One of the most common rare inherited bleeding disorders, congenital factor VII (FVII) deficiency typically has a milder bleeding phenotype than other rare bleeding disorders. Categorizing severity in terms of factor activity associated with hemophilia (severe