Multicenter study to determine the diagnosis criteria of heterozygous familial hypercholesterolemia in Japan. 
Heterozygous patients of familial hypercholesterolemia (FH) are known to have a high risk of coronary artery disease (CAD).  Early diagnosis and prompt treatment are necessary to prevent their CAD.  In this study we tried to amend the Japanese diagnostic criteria of FH for general practitioners by examining each component of the current criteria.  A multicenter study was performed, which included 1356 dyslipidemic patients at 6 centers.  Pretreatment demographic information including LDL-cholesterol (LDL-C), Achilles tendon thickness (ATT), family history of FH and premature CAD and the result of genetic analysis were analyzed.  Of 1356 patients, 419 were diagnosed with FH by criteria in 1988, which were used as a golden standard.  We tried to define FH according to 3 conventional major items, i.e., 1) LDL-C, 2) ATT and/or cutaneous nodular xanthomas (CX), 3) family history of FH and/or family history of premature CAD.  We then determined the cutoff of LDL-C using the new criteria.  When we used 180 mg/dL as the cutoff of LDL-C, 94.3% of FH patients and 0.85% of non-FH satisfied 2 or more criteria.  When we used 190 mg/dL, 92.1% of FH and 0.85% of non-FH satisfied 2 or more criteria; therefore, we chose 180 mg/dL for the cutoff of LDL-C in the new criteria and proposed that the diagnosis of definite FH can be made if 2 or more criteria are satisfied.  We examined each component for the diagnosis of heterozygous FH in a multicenter study in Japan.