An individual has hypercholesterolemia and has genetic testing. What is the probability that their phenotype is 'familial hypercholesterolemia' (FH) caused by an FH-causal mutation? Or what is the probability that it has a multi-factorial (polygenic) cause? HyperLDL-C Sourcery has been designed to answer these questions to help determine the 'source' of hypercholesterolemia. One might think that detection of a 'pathogenic' variant in an FH-related gene is answer enough... but is it really? This program might surprise you!