Purpose of review To provide an overview about the molecular basis of familial hypercholesterolemia. Recent findings Familial hypercholesterolemia is a common hereditary cause of premature coronary heart disease. It has been estimated that 1 in every 250 individuals has heterozygous familial hypercholesterolemia and that fewer than 1% of patients with familial hypercholesterolemia have been identified across the globe. If heterozygous familial hypercholesterolemia is left untreated, it is likely that coronary heart disease will manifest clinically prior to the age of 55 years and that half of all patients will prematurely die from the consequences of myocardial infarction. It is crucial to understand the molecular basis of familial hypercholesterolemia to diagnose familial hypercholesterolemia properly. Summary The phenotype of familial hypercholesterolemia is caused by more than 1700 mutations the LDLR, apoB and PCSK9 genes, which explains approximately 85% of familial hypercholesterolemia cases. By means of next-generation sequencing, an increasing number of mutations in established and putative novel genes associated with this phenotype have been identified.