In the present study, genetic testing was not carried out by DNA sequencing of candidate genes (LDLR, APOB, PCSK9) and thus premature CAD patients were classified as definite, probable, possible, or no FH (familial hypercholesterolemia) patients only using the most effective DLCN (Dutch Lipid Clinic Network) criteria. Here, APOB is linked to familial hypercholesterolemia.