Efficiency of metabolic screening in childhood cardiomyopathies

Aim To estimate the efficiency of metabolic screening in children's cardiomyopathy. Methods and Results Blood glucose, lactate, pyruvate and ketone body, and carnitine levels were measured in 58 children referred with a cardiomyopathy of unknown origin. Organic acids, amino acids, oxidation of [1-C-14] fatty acids to CO2 and dehydrogenation of[9,10(-3)H] fatty acids by lymphocytes were measured. Mitochondrial respiratory chain complex activity was measured in skeletal muscle and in endomyocardial biopsies. Acid alpha-glucosidase activity was measured in infants with hypertrophic cardiomyopathy. The prevalence of metabolic disorders was 22.4% (13/58-CL95%: 11.4-33.3%): four infants had a storage disease (Pompe's disease (3), Hurler's disease (1); two patients had a fatty acid beta-oxidation defect (systemic carnitine deficiency (1) and very-long chain acyl-CoA dehydrogenase deficiency (1)); respiratory enzyme deficiency was diagnosed in seven patients. This defect was confined to the myocardium in six. In the remaining 45 patients, metabolic screening was unrevealing. Conclusion Metabolic screening should be performed in all children with cardiomyopathy as the prevalence of metabolic disorders is high in this population. This may help to define therapeutic strategy and to improve genetic counselling.