Identification of the Intron 22 and Intron 1 Inversions of the Factor VIII Gene in Iraqi Kurdish Patients With Hemophilia A

Abstract

Hemophilia A (HA) is a severe coagulation disorder affecting 1 in 5000 to 10 000 male births. In severe cases, the most deleterious large DNA rearrangements are inversions of intron 22 (Inv22) and intron 1 (Inv1) of the factor VIII (FVIII) gene. These account for 40% to 50% and 1% to 5% of all causative mutations, respectively. Nevertheless, no genetic analysis to identify the actual causative mutation of FVIII, particularly Inv22 and Inv1, among Iraqi Kurdish hemophiliacs has been performed. In this study, we aimed to genotype Inv22 and Inv1 of the FVIII gene in our patients with HA and reveal the genotype/phenotype correlation with the inversion mutations and their role as a risk factor for the development of inhibitors. Analyses of the Inv22 and Inv1 mutations in 80 Iraqi Kurdish patients with HA (60 severe, 18 moderate, and 2 mild) were performed using the inverse shifting–polymerase chain reaction (IS-PCR) method. In severe cases, 46.7% (28/60) had Inv22 and 3.3% (2/60) had Inv1. The genotype/phenotype relation of Inv22 and Inv1 illustrated a statistically significant association ( P = .012) between disease severity and inversion mutations. Slightly more patients with Inv22 (39%) developed inhibitors than those without Inv22 (28%; odds ratio = 1.65, 95% confidence interval = 0.56-4.87, P = .361). Inv22 is a major cause of severe HA in Iraqi Kurdish patients, and IS-PCR is a rapid, robust, and effective method that can be applied for carrier detection and prenatal diagnosis of HA in developing countries.