INTRODUCTION. Mitochondrial long chain fatty acid oxidation provides the major source of energy for the skeletal muscles, heart, brain and liver. Long chain 3-hydroxyacyl- CoA dehydrogenase (LCHAD) catalyses the third step in β-oxidation. LCHAD deficiency (LCHADD) is a rare autosomal recessive metabolic disorder, which may cause sudden unexplained death in childhood, acute hepatic encephalopathy and skeletal myopathy. Laboratory abnormalities characterizing the disease are nonketotic hypoglycaemia, and elevated activities of transaminases and creatine kinase. During pregnancy, LCHADD in the fetus can cause HELLP (hemolysis, elevated liver enzymes, low platelets) syndrome in the mother. Mortality from LCHADD is up to 40%. Death is mainly caused by acute metabolic decompensation, which is provoked by metabolic stress (intercurrent disease, fasting and/or physical exercise). Effective treatment for LCHADD is a low-fat-highcarbohydrate diet, which signifi cantly reduces mortality and improves long-term outcome. The diagnosis is possible by measurement of serum acylcarnitines by tandem mass spectrometric (MS/MS) analysis.
CASE REPORT. Here we describe an acute case of LCHADD in an infant. The boy was born prematurely in the 28th gestational week. His early and late neonatal development and weight gain was normal. At the age of 6 months the child was hospitalized due to acute upper respiratory disorder. The child’s condition worsened 6 hrs following hospitalization and hypoglycaemia (0.2 mmol/l) was diagnosed. He child died 10 hrs after hospitalization. The postmortem molecular analysis of LCHAD revealed gene homosygosity of the common mutation 1528G→C and the diagnosis of LCHAD deficiency was confirmed. As we are introducing MS/MS analysis of serum acylcarnitines in Estonia, a retrospective analysis was performed from the newborn´s Guthrie card. The acylcarnitine profile was characteristic of LCHADD.
CONCLUSION. Expanded newborn screening for the acylcarnitine profile by MS/MS provides presymptomatic diagnosis of fatty acid oxidation defects owing to which severe
clinical complications, including infant death, can be prevented.