Abstract: BACKGROUND: Familial hypercholesterolemia (FH) is the best-described autosomal dominant genetic
hypercholesterolemia (GH). Mutations in candidate genes can explain a high proportion of FH
cases, but for many, no causative mutations are detected (designed non-FG-GH), suggesting the existence
of additional genetic variants associated with the disease.
OBJECTIVE: We aimed to identify new single-nucleotide variants (SNVs) located at the 30 untranslated
regions (30UTRs) of the low-density lipoprotein receptor, low-density lipoprotein receptor?related
protein-associated protein 1, ATP-binding cassette sub-family G member 5, and sterol regulatory
element?binding protein 2 genes in non-FH-GH individuals and investigated whether the association
of these SNVs with non-FH-GH could be explained by changes in the affinity of regulatory microRNAs
(miRNA) targeting the sequences modified by the SNVs.
METHODS: The study includes probands with non-FH-GH attending 2 lipid clinics in Spain. We
performed functional analyses of selected variants using a luciferase reporter system. Through in silico
target-prediction tools, we identified miRNAs, which binding to the 30UTR could be affected by the
presence of specific SNVs. We used analogs and inhibitors of these miRNAs to test this possibility.
RESULTS: We identified 11 new SNVs showing significant association with non-FH-GH. We show
that the presence of 4 of these SNVs leads to significant changes in the transcriptional levels of the
reporter gene. Through mechanistic analysis, we identified 2 miRNAs (miR-27a and miR-133-3p) targeting
the 30UTR of sterol regulatory element?binding protein 2 and an additional miRNA (miR-92a)
targeting the 30UTR of low-density lipoprotein receptor?related protein-associated protein 1.
