• Clinical and Experimental Pediatrics
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• v.59 no.sup1
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• pp.41-44
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• 2016

We report here a case of maternal 3-methylcrotonyl-coenzyme A carboxylase (3-MCC) deficiency in a Korean woman. Her 2 infants had elevated 3-hydroxyisovalerylcarnitine (C5-OH) on a neonatal screening test by liquid chromatography-tandem mass spectrometry (LC-MS/MS), but normal results were found on urine organic acid analysis. The patient was subjected to serial testing and we confirmed a maternal 3-MCC deficiency by blood spot and breast milk spot test by LC-MS/MS, serum amino acid analysis, urine organic acid and molecular genetic analysis that found c.838G>T (p.Asp280Tyr) homozygous mutation within exon 9 of the MCCB gene. Especially, we confirmed marked higher levels of C5-OH on breast milk spot by LC-MS/MS, in the case of maternal 3-MCC deficiency vs. controls.

• Clinical and Experimental Pediatrics
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• v.57 no.7
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• pp.329-332
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• 2014

3-methylcrotonyl-coenzyme A carboxylase (3MCC) deficiency is an autosomal recessive disorder in which leucine catabolism is hampered, leading to increased urinary excretion of 3-methylcrotonylglycine. In addition, 3-hydroxyisovalerylcarnitine levels increase in the blood, and the elevated levels form the basis of neonatal screening. 3MCC deficiency symptoms are variable, ranging from neonatal onset with severe neurological abnormality to a normal, asymptomatic phenotype. Although 3MCC deficiency was previously considered to be rare, it has been found to be one of the most common metabolic disorders in newborns after the neonatal screening test using tandem mass spectrometry was introduced. Additionally, asymptomatic 3MCC deficient mothers have been identified due to abnormal results of unaffected baby's neonatal screening test. Some of the 3MCC-deficient mothers show symptoms such as fatigue, myopathy, or metabolic crisis with febrile illnesses. In the current study, we identified an asymptomatic 3MCC deficient mother when she showed abnormal results during a neonatal screening test of a healthy infant.

• Clinical and Experimental Pediatrics
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• v.48 no.5
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• pp.561-564
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• 2005

Isolated deficiency of 3-methylcrotonyl CoA carboxylase is a rare disorder of the catabolic pathway for leucine and many patients have mild symptoms or no symptom. However, the introduction of tandem mass spectrometry in newborn screening has revealed an unexpectedly high incidence of this disorder. We report an asymptomatic premature infant with isolated 3-methylcrotonyl CoA carboxylase deficiency detected by newborn screening program using tandem mass spectrometry. She was born at preterm, 36 weeks of gestation and her birth weight was 1,912 gm. She was delivered by Cesarian section due to maternal preeclampsia and oligohydramnios. An elevation of 3-hydroxyisovalerylcarnitine in a blood sample obtained at Seven days was detected by tandem mass screening. Massively elevated excretion of 3-hydroxyisovalerate and 3-methylcrotonylglycine was detected in the urine collected at 15 days. L-carnitine(100 mg/kg/day) was administrated orally to correct sencondary carnitine deficiency. Carnitine is conjugated with metabolites, to decrease the potential toxic effects. She is asymptomatic to date, and her growth and development are within normal limits.