• Journal of The Korean Society of Inherited Metabolic disease
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• v.22 no.1
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• pp.1-8
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• 2022

Long-chain fatty acid oxidation disorders (LC-FAOD) are an autosomal recessive inherited rare disease group that result in an acute metabolic crisis and chronic energy deficiency owing to the deficiency in an enzyme that converts long-chain fatty acids into energy. LC-FAOD includes carnitine palmitoyltransferase type 1 (CPT1), carnitine-acylcarnitine translocase (CACT), carnitine palmitoyltransferase type 2 (CPT2), very long-chain acyl-CoA dehydrogenase (VLCAD), long-chain 3-hydroxyacyl-CoA dehydrogenase (LCHAD), and trifunctional protein (TFP) deficiencies. Common symptoms of LC-FAOD are hypoketotic hypoglycemia, cardiomyopathy, and myopathy. Depending on symptom onset, the disease can be divided as neonatal period, late infancy and early childhood, adolescence, or adult onset, but symptoms can appear at any time. The neonatal screening test (NBS) can be used to identify the characteristic plasma acylcarnitine profiles for each disease and confirmed by deficient enzyme analysis or molecular testing. Before introduction of NBS, the mortality rate of LC-FAOD was very high. With NBS implementation as routine neonatal care, the mortality rate was dramatically decreased, but severe symptoms such as rhabdomyolysis recur frequently and affect the quality of life. Triheptanoin (Dojolvi^®), the first drug for pediatric and adult patients with molecularly confirmed LC-FAOD, has recently been approved by the US Food and Drug Administration in 2020. In this review, the diagnosis of LC-FAOD and treatment including triheptanoin are summarized.

• Journal of The Korean Society of Inherited Metabolic disease
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• v.22 no.1
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• pp.21-27
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• 2022

Very long-chain acyl-coenzyme A dehydrogenase (VLCAD) deficiency (VLCADD) leads to a defective 𝛽-oxidation, specifically during prolonged fasting, infection, or exercise. Patients with VLCADD usually suffer from cardiomyopathy, hypoketotic hypoglycemia, hepatic dysfunction, exercise intolerance, muscle pain, and rhabdomyolysis, and sometimes succumb to sudden death. VLCADD is generally classified into three phenotypes: severe early-onset cardiac and multiorgan failure, hypoketotic hypoglycemia, and later-onset episodic myopathy. Diagnostic evaluation comprises acylcarnitine analysis, genetic analysis, and VLCAD activity assay. In the acylcarnitine analysis, the key metabolites are C14:1, C14:2, C14, and C12:1. A C14:1 level >1 mmol/L strongly suggests VLCADD. Various treatment recommendations are available for this condition. Dietary management includes decreasing fat content, increasing medium-chain triglyceride levels, and decreasing fasting periods. Supplementation with L-carnitine is controversial. Triheptanoin (a seven-carbon fatty acid triglyceride) treatment demonstrates improvement of cardiac functions. Bezafibrate may improve the quality of life of patients with VLCAD.