Evaluation of intron 22 and intron 1 inversions of the factor 8 gene using an inverse shifting PCR method in severe haemophilia A patients

Haemophilia A (HA) is an X-linked recessive bleeding disorder caused by several mutations in the F8 gene, whose inversion causes most of the mutation in 40% of severe HA patients. Methods such as long distance PCR and southern blot have been exploited to analyse intron 22 inversion in the F8 gene. For this purpose, we used an inverse shifting PCR assay, a novel genetic diagnostic method, for the detection of intron 22 inversion in severe HA patients. A screen for the presence of intron 22 and intron 1 inversions at the F8 gene in 30 Iranian severe HA patients revealed that 47% of patients showed intron 22 inversion (40% type 1 and 7% type 2), while 7% of patients had intron 1 inversion. Among the patients carrying the inversion, 12% developed inhibitors. Inverse shifting PCR is a precise method for assessment of rearrangements related to int 22h and int 1h in patients and carriers of haemophilia A. Since the previous methods of assessing inversion are time-consuming and demanding, this method can be a good replacement.