Clinical outcome of major organic acidemias – A three years follow-up study

Abstract

The term "organic acidemia" or "organic aciduria" (OA) applies to inborn errors of metabolism (IEM) in which organic acids accumulate in tissues and biological fluids. Classical organic acidurias include methylmalonic aciduria (MMA), propionic aciduria (PA), isovaleric aciduria (IVA) and maple syrup urine disease (MSUD). Aminoacidurias like phenylketonuria are common in the western population. Organic acidemias like MMA, PA and MSUD are more common in Asian countries, especially in India compared with the west. This study was conducted to determine the prevalence and treatment outcome of organic acidemias in a study population in India. Four hundred and twenty suspected cases of organic acidemias with an upper age limit of twelve years were enrolled over a two years period beteween January, 2007 and December, 2008, with a three years patient follow-up. Screening tests and thin layer chromatography followed by quantification of organic acids in urine and quantification of amino acids in blood by high performance liquid chromatography were done for detection of organic acidemias. Out of 420 patients, 45 patients (10.7%) were found to have organic acidemias, 15 cases of MMA, 16 cases of PA, 13 cases of MSUD, and one case of IVA were identified. Fifteen patients (33.3%) died during the course and remaining 30 are under therapeutic regimen and showed marked clinical improvement. Therapeutic regimens based on protein restriction, sodium bicarbonate (to correct acidosis), L-carnitine and vitamins were given to the patients. Prompt diagnosis helped to provide specific treatment to majority of these patients with rapid improvement in symptomatology.

Keywords

Organic acidemias - maple syrup urine disease - methylmalonic aiciduria - propionic aciduria - isovaleric aciduria - tandem mass spectrometry