OBJECTIVETo screen and diagnose fatty acid oxidation disorders (FAOD) in high risk children with inborn error of metabolism using tandem mass spectrometry.

METHODSThe study group consisting of 2941 high risk cases of suspected inborn error of metabolism was tested. The acylcarnitines in the dry blood filter papers of patients were tested by tandem mass spectrometry. The diagnosis of FAOD was according to the levels of the acylcarnitines, the clinical symptoms, and other biochemistry study.

RESULTSFourteen patients were diagnosed as FAOD. These patients included one carnitine palmitoyltransferase deficiency I, one carnitine palmitoyltransferase deficiency II, one short-chain acyl-CoA dehydrogenase deficiency, seven medium-chain acyl-CoA dehydrogenase deficiency, two very long-chain acyl-CoA dehydrogenase deficiency, and two multiple acyl-CoA dehydrogenase deficiency.

CONCLUSIONFAOD are not rare in China. Analysis of acylcarnitines levels tested by tandem mass spectrometry is helpful to diagnose FAOD.

Adolescent ; Amino Acid Metabolism, Inborn Errors ; diagnosis ; genetics ; Carnitine ; analogs & derivatives ; chemistry ; Child ; Child, Preschool ; Female ; Humans ; Infant ; Infant, Newborn ; Lipid Metabolism ; physiology ; Lipid Metabolism, Inborn Errors ; diagnosis ; Male ; Mass Spectrometry ; Tandem Mass Spectrometry ; methods

Medium-chain acyl-CoA dehydrogenase deficiency (MCADD) is an autosomal recessive hereditary metabolic disorder of mitochondrial fatty acid beta-oxidation. It is characterized by hypoketotic hypoglycemia, hyperammonemia, seizure, coma, and sudden infant death syndrome-like illness. The most frequently isolated mutation in the acyl-CoA dehydrogenase, medium-chain (ACADM) gene of Caucasian patients with MCADD is c.985A>G, but ethnic variations exist in the frequency of this mutation. Here, we describe 2 Korean pediatric cases of MCADD, which was detected during newborn screening by tandem mass spectrometry and confirmed by molecular analysis. The levels of medium-chain acylcarnitines, including octanoylcarnitine (C8), hexanoylcarnitine (C6), and decanoylcarnitine (C10), were typically elevated. Molecular studies revealed that Patient 1 was a compound heterozygote for c.449_452delCTGA (p.Thr150ArgfsX4) and c.461T>G (p.L154W) mutations, and Patient 2 was a compound heterozygote for c.449_452delCTGA (p.Thr150ArgfsX4) and c.1189T>A (p.Y397N) mutations. We detected asymptomatic patients with MCADD by using a newborn screening test and confirmed it by ACADM mutation analysis. This report presents evidence of the biochemical and molecular features of MCADD in Korean patients and, to the best of our knowledge, this is the first report of the c.461T>G mutation in the ACADM gene.
Acyl-CoA Dehydrogenase/chemistry/deficiency/genetics ; Asian Continental Ancestry Group/*genetics ; Base Sequence ; Biological Markers/blood ; Carnitine/analogs & derivatives/blood ; DNA Mutational Analysis ; Exons ; Female ; Gene Deletion ; Heterozygote ; Humans ; Infant, Newborn ; Lipid Metabolism, Inborn Errors/diagnosis/genetics ; Male ; Mutation ; Neonatal Screening ; Republic of Korea ; Tandem Mass Spectrometry