We report a case of heterozygous familial hypercholesterolemia (HeFH) in a 36-year-old man with premature coronary artery disease (CAD). Hypercholesterolemia was found in family members including his mother, wife and all 3 of his children (2 boys aged 6 and 3 years, 1 girl aged 4 years). Genetic analysis revealed a GA substitution at nucleotide 682, resulting in Glu207 to Lys (E207K) mutation of the ligand-binding domain of the low-density lipoprotein receptor (LDLR) of all the family members with hypercholesterolemia except for the proband’s wife. Genetic study showed that this mutation was inherited from the proband’s mother then transmitted to all 3 children. Detection of this mutation identifies the cause of hypercholesterolemia and allows appropriate early treatment to prevent premature CAD.