Mutation type Factor 8 gene % reported1 Factor 9 gene % reported2 Missense /nonsense 60 64 Splicing 6.5 9 Regulatory 0.5 2.5 Small deletions 16.5 13 Small insertions 5 3.5 Small indels 1 1 Gross deletions/duplications 9 5.5 Gross insertions 1 0.5 Complex rearrangements 0.5 1 1HGMD®, Human Gene Mutation Database. http://www.hgmd.cf.ac.uk/ac/gene.php?gene=F8 . This frequency distribution excludes the common inversion involving intron 1 and 22 seen in 45-50% of patients with severe hemophilia A . 2HGMD®, Human Gene Mutation Database. http://www.hgmd.cf.ac.uk/ac/gene.php?gene=F9

Table 2: Frequency of disease-causing mutations reported in factor 8 and factor 9 genes