Incidence of carnitine transporter OCTN2 deficiency in Japanese patients with idiopathic cardiomyopathy

点击翻译按钮获取中文摘要

Primary systemic carnitine deficiency. (SCD) is a rare mborn metabolic disease characterized by progressive cardiomyopathy, muscle weakness, and Reye-like syndrome. SCD is responsible for themutations of carnitine transporter OCTN2 gene. It is reported that cardiomyopathy is only symptom in some Caucasian patients with SCD. It is supposed that SCD is overlooked as idiopathic cardiomyopahty although this disease is also known to be treatable with L-carnitine administration. Thus, we investigated the incidence of carnitine transporter deficiency in unrelated 42 Japanese patients with idiopathic cardiomyopathy who live in Akita prefecture (mean age: 58 years, range of age: 13〜87). We examined serum and urinary carnitne level for screening and determined the values by an enzymatic cycling method using carnitine dehydrogenase. Then, we investigated mutational analysis of OCTN2 gene in subjects with informed consent who showed abnormal carnitine values. The value (mean±SD) of tatal carnitine in serum is 67.2±16.6μM, free carnitine in serum was 56.3±14.5μM, acylcarnitine in serum was 10.9±3.7μM, free carnitine in urine was 90.3±150.4μmol/g Creatinine, and acylcarnitine in urine was 93.2±50.3μmol/g Creatinine. Although we found a subject who showed subnormal carnitine level, we detected no mutation in OCTN2 gene. Consequently, we found no patient with SCD in 42 Japanese patients with idiopathic cardiomyopathy. We suggested that the incidence of carnitine transporter deficiency in Japanese patients who showed only cardiac symptoms is relatively low.