Mutation analysis in 51 patients with haemophilia A: report of 10 novel mutations and correlations between genotype and clinical phenotype

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Abstract
Summary. We report the results of genetic analysis on a series of 51 patients attending this Haemophilia Comprehensive Care Centre. The most common cause of severe haemophilia A – the factor VIII intron 22 inversion was detected in eight families and the factor VIII intron 1 inversion in three families. Mutation analysis was carried out on the remaining patients by nucleotide sequencing of genomic DNA after screening with conformation‐sensitive gel electrophoresis (CSGE) or denaturing high‐performance liquid chromatography (dHPLC). A total of 27 different FVIII non‐inversion mutations were detected. Severe haemophilia was associated with 12 null mutations (six nonsense, six frameshift) and four missense mutations. A further 11 different missense mutations were associated with moderate or mild disease. To our knowledge, six null mutations [1950del 4(tttg), 3270–75insA, 4416del 10, 6735–38delA, W1029X, Y1792X] and four missense mutations (E1682K, M1947V, P2048L, P2143L) have not been previously published. Each novel missense mutation occurred at a highly conserved residue, no other candidate mutation was detected on screening the entire coding region of the FVIII gene and they were not detected in a screen of individuals without haemophilia A. The genotype–phenotype correlations of the FVIII mutations detected will be discussed.