Selective Screening of Fatty Acids Oxidation Defects and Organic Acidemias by Liquid Chromatography/tandem Mass Spectrometry Acylcarnitine Analysis in Brazilian Patients.

BACKGROUND

Inborn errors of metabolism (IEM) are diseases which can lead to accumulation of toxic metabolites in the organism.

AIM OF THE STUDY

To investigate, by selective screening, mitochondrial fatty acid oxidation defects (FAOD) and organic acidemias in Brazilian individuals with clinical suspicion of IEM.

METHODS

A total of 7,268 individuals, from different regions of Brazil, had whole blood samples impregnated on filter paper which were submitted to the acylcarnitines analysis by liquid chromatography/tandem mass spectrometry (LC/MS/MS) at the Medical Genetics Service of Hospital de Clínicas de Porto Alegre, Brazil, during July 2008-July 2016.

RESULTS

Our results showed that 68 patients (0.93%) were diagnosed with FAOD (19 cases) and organic acidemias (49 cases). The most prevalent FAOD was multiple acyl CoA dehydrogenase deficiency (MADD), whereas glutaric type I and 3-OH-3-methylglutaric acidemias were the most frequent disorders of organic acid metabolism. Neurologic symptoms and metabolic acidosis were the most common clinical and laboratory features, whereas the average age of the patients at diagnosis was 2.3 years.

CONCLUSIONS

Results demonstrated a high incidence of glutaric acidemia type I and 3-OH-3- methylglutaric acidemia in Brazil and an unexpectedly low incidence of FAOD, particularly medium-chain acyl-CoA dehydrogenase deficiency (MCADD).