Large Intron Inversions in Romanian Patients with Hemophilia A-First Report.

: Despite the vast heterogeneity in the genetic defects causing hemophilia A (HA), large intron inversions represent a major cause of disease, accounting for almost half of the cases of severe HA worldwide. We investigated the intron 22 and intron 1 inversion status in a cohort of Romanian unrelated patients with severe HA. Moreover, we evaluated the role of these inversions as relative risk factors in inhibitor occurrence. : Inverse shifting-a polymerase chain reaction method was used to detect the presence of intron 22 and intron 1 inversions in 156 Romanian patients with HA. : Intron inversion 22 was found in 41.7% of the patients, while intron 1 inversion was detected in 3.2% of the patients. Overall, large intron inversions represented the molecular defect in 44.9% of the studied patients. Our findings are in accord with previously published reports from Eastern Europe countries and with other international studies. The risk of inhibitor development was higher in patients with inversion 1 compared to the patients with HA without any inversion detected. : The current study demonstrates the major causative role of large intron inversions in severe HA in Romanian patients. Moreover, our study confirms the contribution of intron 1 inversion in inhibitor development.