Le acidure organiche

Abstract

Organic acidurias are congenital metabolic disorders variously involving the metabolic pathways, mainly the catabolism of aminoacids and fatty acids with accumulation of one or more organic acids in blood or urine. This group of diseases includes over 50 specific forms which, although rare, are the most common cause of acute encephalopathy in infancy.

Single or recurrent episodes of metabolic failure are the most frequent presenting symptom in infancy, often in the first weeks of life. Onset may also occur later with features of chronic encephalopathy and complex clinical features including seizures, dystonia, hypotonia and in some cases myopathies associated with liver and kidney failure. Early diagnosis of acute forms is important since some organic acidurias can be treated thus preventing often fatal episodes of metabolic failure or ongoing neurological damage.

Definitive diagnosis requires a search for pathological metabolites in urine using gas chromatography and mass spectroscopy and confirmation of enzyme deficit. Neurological investigation will show features indicative of metabolic disease in acute forms and in children presenting with progressive encephalopathy. Neurological features are heterogeneous, but MR findings will offer information for subsequent biochemical tests and sometimes suggest diagnosis, especially signal changes in the basal nuclei and subcortical white matter.