Prevalence of Red Cell Phenotypes Among Blood Donors in King Fahd Hospital of the University, Al-Khobar

Abstract

von Willebrand disease (VWD) is a congenital autosomal bleeding disorder and it has been recognized as the most common disorder of bleeding among individuals. The incidence rate is approximately reaching to 1% of the general population. The occurrence of VWD is alike in ethnic groups and it affects both females and males. All abnormalities of VWF protein in the plasma of patients are classified into two (qualitative and quantitative VWF defects). These abnormalities are appeared due to changes in VWF gene which cause VWD with symptoms include mild or severe mucocutaneous bleeding.About 55% to 70% of all VWD patients represent a reduction in the plasma glycoprotein von Willebrand factor (VWF) concentrations and this is classified as type 1 VWD, while the concentrations of VWF can be normal in type 2 VWD but the problem is that the VWF does not work properly. Individuals with type 3 VWD have very low or no levels of VWF and this is the most severe and rarest type. The diagnosis of patients with type 1 VWD could be difficult mainly in the mild cases, because of the difficulty in phenotypically distinguish between these patients and healthy people with low VWF levels.The total 100 blood samples were tested for CBC, PT, APTT, VWF Ag, VWF activity (RiCo), and FVIII. 11 (11%) of them had prolonged PT (<14.5 sec), 14 (14%) had prolonged APTT (<40 sec), one (1%) had low levels of platelets (>150,000 plts/μl), one (1%) male sample with O blood group had reduced level of VWF Ag (>50%), 9 (9%) samples with O blood group had reduced level of RiCo (>50%), six (6%) of them were males and three (3%) females, and two (2%) male and female samples with O blood group had low FVIII level ( >60%).Genotyping of VWF gene was required to establish a diagnostic method for type 1 VWD in Kingdom of Saudi Arabia. This was due to the poorly understanding of the disorder molecular basis, and the restricted studies those have been shown on type 1 VWD in KSA. VWF variants were identified in 55 persons (55%) of participants, leaving 45% with no detected changes. A total of 40 different VWF gene variations were identified. Synonymous variations were the most frequent 19 variations followed by 17 missense variations, two stop gained variations, one coding sequence variation, and one 500B downstream variation. 43% of the participants had more than one VWF variation detected.