Prolonged exercise testing in two children with a mild Multiple Acyl-CoA-Dehydrogenase deficiency.
BACKGROUND: Multiple Acyl-CoA-Dehydrogenase deficiency (MADD) is an inherited metabolic disorder characterized by impaired oxidation of fatty acids and some amino acids. METHODS: We were interested whether children with MADD could tolerate a prolonged low-intensity exercise test and if this test could have any additional diagnostic value. Therefore, we performed a maximal exercise test and a low-intensity prolonged exercise test in 2 patients with MADD and in 5 control subjects. During a prolonged exercise test the subjects exercised on a cycle ergometer at a constant workload of 30% of their maximum for 90 minutes and heart rate, oxygen uptake, fuel utilization and changes in relevant blood and urinary parameters were monitored. RESULTS: The tests were tolerated well. During the prolonged exercise test the fatty acid oxidation (FAO) was quite low compared to 5 control subjects, while characteristic metabolites of MADD appeared in plasma and urine. CONCLUSION: We suggest that the prolonged exercise test could be of diagnostic importance and might replace the fasting test as a diagnostic procedure in some cases, particularly in patients with anamnestic signs of intolerance for prolonged exercise.
Takken
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Department of Pediatric Physical Therapy & Exercise Physiology, University Hospital for Children and Youth 'Het Wilhelmina Kinderziekenhuis', University Medical Centre Utrecht, Utrecht, The Netherlands. t.takken@umcutrecht.nl.
Custers
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Visser
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Dorland
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Helders
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de Koning
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