Subjects
All patients with either hemophilia A or B, registered in the PedNet registry by 1 January 2018 (n=1967) were included. Data on patients’ demographics, type and severity of hemophilia, and family history of hemophilia were collected. Reports on genotyping collected from each single center were then classified uniformly by a central genetic laboratory according to the recommendations of the Human Genome Variation Society (HGVS). Mutation nomenclature was based on the following transcripts: NM_000132.3 (F8) and NM_000133.3 (F9) and GRCh38 genome build. All mutations were cross-checked with the CDC-based databases CHAMPS and CHBMPS, the EAHAD database and the HGMD (Human Genome Mutation database) and a literature search on 1 January 2020, and only mutations not described in these databases or published in a scientific journal searchable on Medline were included in this manuscript; these are referred to as ‘new variants’.