Vladimír Bzdúch, Darina Behúlová, Katarína Fabriciová, Jörg Oliver Sass
Fatty acid β-oxidation (FAO) defects have become one of the most important group of inherited metabolic disorders, with broad clinical spectrum varying from sudden infant death to almost asymptomatic adults. The two major types of presentation are typical: a form with signs of acute hepatoencephalic involvement and form with predominantly muscle and cardiac involvement. Hepatoencephalic involvement or Reye-like syndrome includes hypoketotic hypoglycemia, moderate hepatomegaly with increased serum aminotransferases, low free carnitine in serum, mild acidosis and mild hyperammonemia. The second presentation reflects the chronic disruption of muscle function with myopathy and cardiomyopathy with symptoms such as progressive muscular weakness, episodic muscle pain, rhabdomyolysis, elevated creatine kinase, myoglobinuria and cardiac conduction. All kinds of FAO disorders except carnitine palmitoyltransferase I (CPT I) and medium-chain acyl-CoA dehydrogenase (MCAD) deficiency present with significant muscular signs. MCAD deficiency has emerged as the most frequently diagnosed inborn error of mitochondrial fatty acid β-oxidation. The Roma people should be considered as a group at risk for MCAD deficiency. This disorder is associated with significant risk of sudden death or permanent damage of the central nervous system. The early diagnosis is very important, so simple and effective therapy can be applied. MCAD deficiency is considered as a favorable candidate for newborn screening. Long-chain fatty acid oxidation defects present with heterogeneous clinical phenotypes and symptoms of short-chain acyl-CoA dehydrogenase deficiency are non-specific and generally uncomplicated. In countries, where screening by tandem mass spectrometry is not available, knowledge of symptoms FAO disorders is very important for better selective screening.