A functional mutation in the LDLR promoter (-139C>G) in a patient with familial hypercholesterolemia

A novel sequence change in repeat 3 of the promoter of the low-density lipoprotein receptor (LDLR) gene, -139C4G, has been identified in a patient with familial hypercholesterolemia (FH). LDLR-139G has been passed to one offspring who also shows an FH phenotype. Transient transfection studies using luciferase gene reporter assays revealed a considerable reduction (74 +/- 71.4% SEM) in reporter gene expression from the -139G variant sequence compared to the wild-type sequence, strongly suggesting that this change is the basis for FH in these patients. Analysis using electrophoretic mobility shift assay demonstrated the loss of Sp1 binding to the variant sequence in vitro, explaining the reduction of transcription.