Diagnosis and management of defects of mitochondrial beta-oxidation.
OBJECTIVE
At least 22 different inborn errors of metabolism affecting beta-oxidation in skeletal muscle and other tissues have been identified in the past 30 years. Early diagnosis and therapeutic diets offer the best chance for normal growth and development in most patients.


RESULTS
Clinical heterogeneity has become the hallmark of defects in beta-oxidation. In many cases a correct diagnosis will only be made if these disorders are specifically considered and appropriate studies are obtained, since screening tests which detect other inborn errors of metabolism are often normal in patients with beta-oxidation defects. Dietary management provides the only opportunity for therapy in many cases, including carbohydrate supplements intended to provide more extended delivery of glucose to the bloodstream. Use of a novel odd chain fat supplement as an alternative fuel source in long chain fat metabolism defects offers promise of alleviating muscular symptoms not well controlled by diet. The introduction of expanded newborn screening will lead to the recognition of an increasing number of individuals with these disorders, placing greater demand for services on practitioners knowledgeable in their therapy. Study of the clinical outcome in these patients will provide a better understanding of defects of beta-oxidation.


CONCLUSIONS
Clinical symptoms, diagnostic testing, and issues of newborn screening for this important group of disorders are discussed.
Vockley
Jerry
J
Department of Medical Genetics and Department of Biochemistry and Molecular Biology, Mayo Clinic and Foundation, Rochester, Minnesota 55905, USA. vockley@mayo.edu
Singh
Rani H
RH
Whiteman
David A H
DA
D005227:Fatty Acids / Q000378:metabolism*; D006801:Humans; D008052:Lipid Metabolism, Inborn Errors / Q000175:diagnosis / Q000178:diet therapy; D008661:Metabolism, Inborn Errors / Q000175:diagnosis* / Q000178:diet therapy* / Q000201:enzymology; D008928:Mitochondria / Q000378:metabolism*; D010084:Oxidation-Reduction
D005227:Fatty Acids