Clinical Biochemical and Molecular Genetic Profile of Organic Acidurias

Abstract

Organic acid disorders are inherited metabolic disorders (IEM) in which organic acids accumulate in tissues and biological fluids of affected individuals. Classical organic acidurias include methylmalonic aciduria (MMA), propionic aciduria (PA), isovaleric aciduria (IVA) and maple syrup urine disease (MSUD). They are considered the most frequent metabolic disorders among severely ill children. Patients frequently present with acute symptoms early in life. Organic acidemias are more common in Asian countries, especially in India compared with the west. This study was conducted to determine the prevalence, treatment outcome and molecular genetic aspects of organic acidemias in a study population in South 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 between January, 2007 and December, 2008, with a three years patient follow-up. Screening tests and TLC 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 methylamlonic acidemia, 16 cases of propionic acidemia, 13 cases of maple syrup urine disease, and one case of isovaleric acidemia. Fifteen patients (33.3%) died during the course and remaining 30 showed marked clinical improvement. Prompt diagnosis helped to provide specific treatment to majority of these patients with rapid improvement in symptomatology. Since organic acidemia may cause irreversible brain damage if not treated, we recommend selective screening amongst severely ill children despite newlineimplied extra costs. . newline