Methylmalonic Acidemia- A Rare Inborn Error of Metabolism

Abstract

The methylmalonic acidemias (MMA) are a heterogeneous group of autosomal recessive inborn errors of organic acid metabolism. The hallmark of MMA is hyperammonemia, encephalopathy and metabolic acidosis in infancy and especially so in neonatal age group. Management of such cases is often challenging and is associated with variable outcome. We present a nine day old male child who was referred to us with vomiting, lethargy and myoclonic seizures. Organic acidemia was thought of, because the neonate had metabolic acidosis with increased anion gap along with hyperammonemia, ketonuria and hypoglycemia. Tandem mass spectrometry along with Gas Chromatography-Mass Spectrophotometry helped us to clinch the diagnosis of methylmalonic acidema in our neonate. Patient was symptomatically managed along with carnitine and multivitamin supplements. He was sent home with advice of regular follow-up.

Keywords

• gas chromatography-mass spectrophotometry
• hyperammonemia
• metabolic acidosis
• organic aciduria
• tandem mass spectrometry