Clinical and laboratory findings and outcomes of classic organic acidurias in children from north-eastern Thailand: a 5-year retrospective study

Background: Classic organic acidurias, including isovaleric aciduria (IVA), propionic aciduria (PA) and methylmalonic aciduria (MMA), are rare inherited metabolic disorders caused by deficiencies of enzymes in catabolic pathways. Objective: To report clinical and laboratory findings and outcomes of classic organic acidurias in children north-eastern Thailand and their outcomes over the past 5 years. Methods: During 2010?2014, twelve patients were identified as having classic organic acidurias confirmed by urine organic acids analysis. Results: Classic organic acidurias were identified as follows; 5 patients with IVA, 4 patients with PA, and 3 patients with MMA. Ten patients had neonatal-onset and 9 cases were diagnosed during the neonatal period with clinical signs and symptoms of altered consciousness, poor feeding, respiratory distress, abnormal odor, and shock. Common laboratory findings included metabolic acidosis with an elevated anion gap, hyperammonemia, hypocalcemia, and cytopenia. Ammonia levels could be extremely high, especially in PA. Three patients with neonatal-onset of acidurias died during their first catabolic crisis, and one patient died later. One patient with MMA had exfoliative erythema after excessive dietary restriction. Four of 8 surviving patients had IVA and had better neurodevelopmental outcomes than those with PA and MMA. Conclusion: Neonatal-onset classic organic acidurias are more common than late-onset cases and usually mimic neonatal sepsis. Laboratory findings that include hematologic abnormalities should raise suspicion. Close monitoring of biochemical parameters, growth and neurodevelopmental outcomes is necessary in a long-term follow-up. Keywords: Isovaleric aciduria, methylmalonic aciduria,neutropenia, organic acidurias, propionic aciduria