Abstract
A 3.5-years-old girl suddenly developed unconsciousness and seizures in the morning. Blood glucose level was 0.8 mmol/l.
Two days later, fasting asymptomatic hypoglycemia 1.5 mmol/l occurred in spite of physiologically suppressed insulin secretion and exaggerated cortisol and growth hormone secretion. Metabolic investigation proved dicarboxylic aciduria with presence of hexanoyl-glycine.
Serum carnitin deficiency was also found. These findings were suggestive to the deficiency of a medium chain acyl-CoA dehydrogenase (MCAD), one of the enzymes acting in the mitochondrial fatty acid beta-oxidation.
DNA analysis in this patient proved a compound heterozygocity for a prevalent mutation A985G and for a new deletion T474/475 in the MCAD gene. A brother of the girl suddenly died five years earlier at his third day of life.
His autopsy revealed steatotic liver and myocardium. Defects of fatty acid oxidation are of the most serious causes of childhood hypoglycemias but their symptoms may be prevented by simple dietary measurements.
Metabolic investigation of blood samples taken at hypoglycemia and a subsequent in vitro analysis of beta-oxidation in lymphocytes are decisive for the correct diagnosis of these disorders.