1. Analysis of LDLR variants from homozygous FH patients carrying multiple mutations in the LDLR gene
- Author
-
Wei Cui, Lu-Ya Wang, Kepa B. Uribe, Aitor Etxebarria, Xiao-Dong Pan, César Martín, Ling Tang, Yu-Jie Zhou, Helena Ostolaza, Shi-Wei Yang, Asier Benito-Vicente, and Long Jiang
- Subjects
Adult ,Genetic Markers ,Male ,0301 basic medicine ,Proband ,Heredity ,DNA Mutational Analysis ,Mutant ,CHO Cells ,Familial hypercholesterolemia ,Biology ,Transfection ,medicine.disease_cause ,Hyperlipoproteinemia Type II ,Young Adult ,03 medical and health sciences ,Cricetulus ,INDEL Mutation ,Risk Factors ,medicine ,Animals ,Humans ,Genetic Predisposition to Disease ,Child ,Exome sequencing ,Genetics ,Mutation ,Homozygote ,Infant ,Autosomal dominant trait ,medicine.disease ,Molecular biology ,Pedigree ,Phenotype ,030104 developmental biology ,Receptors, LDL ,Genetic marker ,LDL receptor ,Female ,Cardiology and Cardiovascular Medicine - Abstract
Background and aims Familial hypercholesterolemia (FH) is an autosomal dominant disease with widespread global prevalence that partially accounts for the high prevalence of premature coronary heart disease. Although the majority of research on FH has focused on single heterozygous LDLR mutations, there have been limited reports of double LDLR mutations on the same chromosome. The aim of this study was to gain insight into the clinical consequences of the presence of multiple mutations in the LDLR gene. Methods DNA from two clinical homozygous FH patients and their relatives was analysed using targeted exome sequencing and DNA resequencing. Functional characterization of novel variants was performed by Western blot, flow cytometry and confocal microscopy. Results Proband 1 carried p.Q12X, NTDA (p.N276T and c.892delA) mutations in LDLR , and Proband 2 carried c.971delG, GSDN (p.G77S + D601N). Results showed that p.Q12X, c.892delA, and c.971delG are non-functional LDLR variants. Conversely, N276T and G77S are non-pathogenic variants. Interestingly, while D601N alone only slightly diminishes LDLR activity, its co-presence with the non pathogenic p.G77S mutation results in a more strongly pathogenic variant with LDLR activity reduced by 40%. One of the double mutants, NTDA, is as non functional as c.892delA alone. The other double mutant, GSDN, is more severe than either of the component single mutants. Conclusions An early gene screening and laboratory functional verification of LDLR activity is of vital importance to enable a definite FH diagnosis. Functional verification is also necessary for prenatal and postnatal care in patients with FH.
- Published
- 2017
- Full Text
- View/download PDF