Genomic alterations in the F8 gene correlating with severe hemophilia A in Egyptian patients

Abstract

Background: Hemophilia A (HA) is an inherited X-linked recessive coagulation disorder caused by factor VIII (F8) deficiency. F8 rearrangements involving intron 22 (int22) and intron 1 (int1) account for almost half of severe HA phenotype also a hotspot exon 14 provides numerous mutational patterns. This study aims to identify F8 gene mutations among Egyptian HA patients. Methods: DNA samples from 60 HA patients were screened for int22 and int1 rearrangements using simplified inverse shifting PCR (IS-PCR) followed by exon 14 sequencing. Also, four uncharacterized patients were studied by targeted exome sequencing. Results: In 33.3% of the studied patients, we identified three int22 rearrangements, three exon 14 mutations (two frameshift; one novel (NM_000132.3:c.2734_2735delAA, p.(N912Ffs*6)), a second reported mutation (NM_000132.3:c.3091_3094delAGAA, p.(K1031Lfs*9)), and one nonsense mutation (NM_000132.3:c.2440C>T, p.(R814*)). All identified mutations were detected in patients with severe HA phenotype. Targeted exome sequencing could not detect any known pathogenic variants. Conclusion: Intron 22 rearrangement and exon 14 mutations correlate with most severe hemophilia A Egyptian patients.