1. Founder mutation identified in the LDLR gene causing familial hypercholesterolemia associated with increased risk of coronary heart disease

Abstract

Basic science research. Presentation Type: Oral presentation. Introduction: Coronary artery diseases (CAD) inflict heavy economical and social cost on most populations including Saudi’s and contribute significantly to their morbidity and mortality rates. Familial hypercholesterolemia (FH) is hereditary in an autosomal dominant disease and is a major risk factor for the development of CAD. FH is predominantly caused by variants in the low-density lipoprotein (LDL) receptor gene (LDLR). Methodology: More than 140 FH samples including 44 probands were collected from 17 unrelated Saudi families who live in the central, northern, western and eastern regions of Saudi Arabia. Patient samples were screened using Next-generation sequencing (NGS) and Capillary sequencing. We described the genetic analysis of severely affected homozygous FH patients who were mostly resistant to statin therapy and were managed on an apheresis program. Results: We identified a common frameshift mutation p. (G676Afs*33) in exon 14 of the LDLR gene in 17 probands and their first-degree blood relatives in apparently unrelated Saudi families. This founder mutation was found in about 40% Saudi FH population. We also describe a three dimensional homology model of the LDL receptor protein (LDLR) structure and examine the consequence of the frameshift mutation p. (G676Afs*33), as this could affect the LDLR structure in a region involved in dimer formation, and protein stability. Conclusion: This finding of a recurrent mutation causing FH in the Saudi population could serve to develop a rapid genetic screening procedure for FH, and the 3D-structure analysis of the mutant LDLR, may provide tools to develop a mechanistic model of the LDLR function.