Phenotypic and Genotypic Signatures of VWF Exon 18 in Eastern Saudi Patients Previously Diagnosed with Type 1 von Willebrand Disease

Faisal M Alzahrani; Asma A Al Faris; Layla A Bashawri; Fathelrahman Mahdi Hassan; Omar S El-Masry; Maryam A Aldossary; Osama Al Sultan; J Francis Borgio; Mohammed A Alsahli; Anne Goodeve

doi:10.2147/IJGM.S364818

Phenotypic and Genotypic Signatures of VWF Exon 18 in Eastern Saudi Patients Previously Diagnosed with Type 1 von Willebrand Disease

Int J Gen Med. 2022 Jun 2:15:5385-5394. doi: 10.2147/IJGM.S364818. eCollection 2022.

Affiliations

¹ Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, Imam Abdulrahman Bin Faisal University, Dammam, Saudi Arabia.
² Department of Hematology and Immunohematology, College of Medical Laboratory Science, Sudan University of Science and Technology, Khartoum, Sudan.
³ Department of Internal Medicine, King Fahad Hospital of the University, Imam Abdulrahman Bin Faisal University, Khobar, Saudi Arabia.
⁴ Department of Genetic Research, Institute for Research and Medical Consultations (IRMC), Imam Abdulrahman Bin Faisal University, Dammam, Saudi Arabia.
⁵ Department of Medical Laboratories, College of Applied Medical Sciences, Qassim University, Buraydah, 51452, Saudi Arabia.
⁶ Medical School, University of Sheffield, Sheffield, UK.

Abstract

Introduction: von Willebrand disease (VWD) is the most prevalent bleeding disease, which is associated with either low levels of von Willebrand factor (VWF) or abnormality in its structure. Three types of the disease have been described; type 1 (VWD1) and 3 (VWD3) are caused by deficiency of VWF and type 2 (VWD2) is caused by production of defective VWF. The aim of the current study was to characterize gene variants of VWF gene; exon 18 in particular, in a cohort of Saudi families as well as healthy control subjects.

Methods: A total of 19 families comprising 60 subjects of type 1 VWD were enrolled in the study. Participants were divided into 22 index cases, 21 affected family members and 17 unaffected family members ranging in age from 6 to 70 years. Blood samples were collected from all participants to measure activated partial thromboplastin time test (APTT), von Willebrand antigen level (VWF:Ag), Factor VIII activity (FVIII:C) and ristocetin cofactor activity (VWF:RCo), platelet count, determining the ABO blood group and for genetic analysis by Sanger sequencing.

Results: The results indicated that VWD1 patients have lower levels of VWF and factor VIII than the non-affected family members and the control subjects. In addition, five gene variants were reported in VWF exon 18; of these, c.2365A>G and c.2385T>C were more common in the control group and might be protective from VWD.

Discussion: In conclusion, VWF levels are influenced by blood group, and there was no association between variants in exon 18 of VWF gene reported in all groups and the disease status; however, blood group analysis and genome-wide genotyping could help to highlight high-risk groups and improve clinical management of VWD.

Keywords: Saudi Arabia; VWF gene; von Willebrand disease.