title: Functional characterization of splicing and ligand-binding domain variants in the LDL receptor.
abstract: Familial hypercholesterolemia (FH) is an autosomal dominant disorder mostly caused by mutations in the LDLR gene. Although the detection of functional mutations in the LDLR gene provides an unequivocal diagnosis of the FH condition, there are many variants whose pathogenicity is still unknown. The aims of this study were to set up a rapid method to determine the effect of LDLR mutations, thereby providing an accurate diagnosis of FH, and to functionally characterize six LDLR mutations detected at high frequency by the LIPOchip(®) platform (Progenika Biopharma, Spain) in the Spanish population. LDLR expression and activity were analyzed by one-single-step flow cytometry assay and confocal microscopy. Splicing effects were determined by sequencing reverse transcription polymerase chain reaction products. The analysis of three heterozygous variants with a single point mutation within the low-density lipoprotein binding domain allowed us to classify the c.806G>A variant as nonpathogenic, and c.862G>A and c.895G>A variants as causative of FH. The results obtained for three variants affecting donor splice sites of the LDLR mRNA, c.313+2dupT, c.1186+5G>A, and c.1845+1G>C, demonstrated that these mutations are pathogenic. These results expand our knowledge of mutations responsible for FH, providing an accurate diagnosis and leading to early treatment to reduce the risk of premature cardiovascular events.
authors: Unidad de Biofísica (Centro Mixto CSIC-UPV/EHU) and Departamento de Bioquímica, Universidad del País Vasco, Apdo. 644, 48080 Bilbao, Spain.
authors: Aitor
authors: A
authors: Etxebarria
authors: Lourdes
authors: L
authors: Palacios
authors: Marianne
authors: M
authors: Stef
authors: Diego
authors: D
authors: Tejedor
authors: Kepa B
authors: KB
authors: Uribe
authors: Amalia
authors: A
authors: Oleaga
authors: Luis
authors: L
authors: Irigoyen
authors: Beatriz
authors: B
authors: Torres
authors: Helena
authors: H
authors: Ostolaza
authors: Cesar
authors: C
authors: Martin
mesh_terms: D001483:Base Sequence; D001665:Binding Sites; D016022:Case-Control Studies; D002478:Cells, Cultured; D004252:DNA Mutational Analysis; D005091:Exons; D015870:Gene Expression; D006579:Heterozygote; D006801:Humans; D006938:Hyperlipoproteinemia Type II / Q000175:diagnosis / Q000235:genetics* / Q000378:metabolism; D008077:Lipoproteins, LDL / Q000378:metabolism*; D008969:Molecular Sequence Data; D017354:Point Mutation; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D022821:RNA Splice Sites; D012326:RNA Splicing; D011973:Receptors, LDL / Q000235:genetics* / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013601:T-Lymphocytes / Q000378:metabolism
chemical_list: D008077:Lipoproteins, LDL; D022821:RNA Splice Sites; D011973:Receptors, LDL