Familial hypercholesterolemia (FH) is the most common genetic metabolic disease in the world. It is caused by an inherited error of cholesterol metabolism. Variants of 3 genes (LDLR, APOB and PCSK9) are the major causes of FH, however, 50-70% of cases can’t be explained by mutations in known genes. Here, we initiate a search of yet undiscovered variants in both known and potentially novel FH-related genes. This will be achieved by subjecting to long-read Nanopore whole genome sequencing DNA of 10 individuals from 2-3 FH families where underlying mutations went undetected with classical genetic methods. Particular attention will be paid to jumping gene insertions as causal variants in FH. These ancient elements are still mobile and able to cause Mendelian diseases via insertional mutagenesis. However, due to their size and repetitive nature, both wet-lab methods and bioinformatic analysis of next generation sequencing data tend to overlook them.