Age, Origin and Functional Study of the Prevalent LDLR Mutation Causing Familial Hypercholesterolaemia in Gran Canaria

The p.(Tyr400_Phe402del) mutation in the LDL receptor (LDLR) gene is the most frequent cause of familial hypercholesterolaemia (FH) in Gran Canaria. The aim of this study was to determine the age and origin of this prevalent founder mutation and to explore its functional consequences. For this purpose, we obtained the haplotypic information of 14 microsatellite loci surrounding the mutation in one homozygous individual and 11 unrelated heterozygous family trios. Eight different mutation carrier haplotypes were identified, which were estimated to originate from a common ancestral haplotype 387 (110–1572) years ago. This estimation suggests that this mutation happened after the Spanish colonisation of the Canary Islands, which took place during the fifteenth century. Comprehensive functional studies of this mutation showed that the expressed LDL receptor was retained in the endoplasmic reticulum, preventing its migration to the cell surface, thus allowing us to classify this LDLR mutation as a class 2a, defective, pathogenic variant.This work was supported by grants from the Instituto de Salud Carlos III (ISCIII): PI20/00846, INT21/00032 (RMS), CM19/00116 (AMGL) with the participation of the European Union through European Regional Development Funds (“A way to make Europe”), the Fundación Canaria del Instituto de Investigaciones Sanitarias de Canarias (FCIISC): PIFIISC20/16 and the Fundación Mapfre Guanarteme (Beca Investigación 2020). NMS was supported by a María Zambrano Fellowship funded by the Spanish Ministry of Universities within the “Next Generation EU” scheme