TY - JOUR
T1 - Acylcarnitine profiles during carnitine loading and fasting tests in a Japanese patient with medium-chain acyl-CoA dehydrogenase deficiency
AU - Yokoi, Kyoko
AU - Ito, Tetsuya
AU - Maeda, Yasuhiro
AU - Nakajima, Yoko
AU - Ueta, Akihito
AU - Nomura, Takayasu
AU - Koyama, Norihisa
AU - Kato, Ineko
AU - Suzuki, Satoshi
AU - Kurono, Yukihisa
AU - Sugiyama, Naruji
AU - Togari, Hajime
PY - 2007/12/12
Y1 - 2007/12/12
N2 - Medium-chain acyl-CoA dehydrogenase deficiency (MCADD) is rare among Asian individuals, and the clinical course and biochemical findings remain unclear. We report herein a 3-year-old Japanese girl with MCADD. The diagnosis was suggested by acylearnitine profiles and confirmed by enzyme activity and genetic analysis after clinical presentation. Our described method with high-performance liquid chromatography/tandem mass spectrometry allows quantification of levels of n-octanoylcarnitine (C8-N) and other isomers (e.g. valproylcarnitine). We examined the patient's acylcarnitine profiles in serum and urine samples during carnitine loading and 14-hr fasting tests with/without camitine supplementation. Under hypocarnitinemia, serum level of C8-N vhs 0.16 μmol/1 and C8-N/decanoylcarnitine (C10) ratio was 1.8, which did not correspond to the diagnostic criteria for MCADD. However, intravenous carnitine loading test (100 mg/kg/day for 3 days and 50 mg/kg/day for 1 day) led to increased serum C8-N levels and urinary excretion was obvious, strongly suggesting MCADD. In the fasting test with carnitine supplementation, marked production of acylcarnitines (C8-N > C2 >> C6 > C10) was found, compared to the fasting test without carnitine supplementation. These results indicate that carnitine supplementation may be useful for detoxification of accumulated acylcarnitines even in an asymptomatic state. Moreover, the one-point estimination for serum C8-N level and/or C8-N/C10 ratio may make the diagnosis of MCADD difficult, particularly in the presence of significant hypocarnitinemia. To avoid this pitfall, attention should be given to serum levels of free carnitine, and carnitine loading may be demanded in hypocarnitinemia.
AB - Medium-chain acyl-CoA dehydrogenase deficiency (MCADD) is rare among Asian individuals, and the clinical course and biochemical findings remain unclear. We report herein a 3-year-old Japanese girl with MCADD. The diagnosis was suggested by acylearnitine profiles and confirmed by enzyme activity and genetic analysis after clinical presentation. Our described method with high-performance liquid chromatography/tandem mass spectrometry allows quantification of levels of n-octanoylcarnitine (C8-N) and other isomers (e.g. valproylcarnitine). We examined the patient's acylcarnitine profiles in serum and urine samples during carnitine loading and 14-hr fasting tests with/without camitine supplementation. Under hypocarnitinemia, serum level of C8-N vhs 0.16 μmol/1 and C8-N/decanoylcarnitine (C10) ratio was 1.8, which did not correspond to the diagnostic criteria for MCADD. However, intravenous carnitine loading test (100 mg/kg/day for 3 days and 50 mg/kg/day for 1 day) led to increased serum C8-N levels and urinary excretion was obvious, strongly suggesting MCADD. In the fasting test with carnitine supplementation, marked production of acylcarnitines (C8-N > C2 >> C6 > C10) was found, compared to the fasting test without carnitine supplementation. These results indicate that carnitine supplementation may be useful for detoxification of accumulated acylcarnitines even in an asymptomatic state. Moreover, the one-point estimination for serum C8-N level and/or C8-N/C10 ratio may make the diagnosis of MCADD difficult, particularly in the presence of significant hypocarnitinemia. To avoid this pitfall, attention should be given to serum levels of free carnitine, and carnitine loading may be demanded in hypocarnitinemia.
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U2 - 10.1620/tjem.213.351
DO - 10.1620/tjem.213.351
M3 - Article
C2 - 18075239
AN - SCOPUS:38049134620
SN - 0040-8727
VL - 213
SP - 351
EP - 359
JO - Tohoku Journal of Experimental Medicine
JF - Tohoku Journal of Experimental Medicine
IS - 4
ER -