Fatty acid oxidation disorders: outcome and long-term prognosis.
Assessing the outcome of fatty acid oxidation disorders is difficult, as most are rare. For diagnosis by newborn screening, the situation is compounded: far more cases are diagnosed by screening than by clinical presentation, representing a somewhat different cohort. The literature on outcome was reviewed. For disorders other than medium-chain acyl-coenzyme A (CoA) dehydrogenase (MCAD) deficiency there was insufficient evidence to make many firm statements. In MCAD deficiency, risk of death in the first 72 h is around 4%, with a further approximately 5-7% fatality rate in the first 6 years but very low subsequent risk in previously undiagnosed patients. The risk of death after diagnosis is very low at any age, with good management. The long-term outcome is good nowadays. Very-long-chain acyl-CoA dehydrogenase deficiency poses a risk of death in early infancy, but the condition is generally treatable, with a good outcome after diagnosis. Approximately 10-20% of patients diagnosed by newborn screening and treated nevertheless suffer episodic rhabdomyolysis. Some patients never become symptomatic. Isolated long-chain 3-hydroxyacyl-CoA dehydrogenase deficiency is treatable, but most patients suffer episodic hypoketotic hypoglycaemia and rhabdomyolysis. Generalised mitochondrial tri-functional protein deficiency has high early mortality rate. A more insidious presentation also occurs, with symptoms sometimes confined to progressive axonal neuropathy. Among carnitine cycle disorders, carnitine transporter deficiency, potentially lethal, is uniformly successfully treated orally with carnitine. Carnitine-acylcarnitine translocase and early-onset carnitine palmitoyl transferase type II (CPT II) deficiencies have an extremely high neonatal mortality rate. Late-onset CPT II is characterised only by episodic rhabdomyolysis on severe exercise. CPT type IA deficiency may often be benign, although early presentation with hypoketotic hypoglycaemia certainly occurs.
Wilcken
Bridget
B
Biochemical Genetics and Newborn Screening, The Children's Hospital at Westmead, Westmead, NSW, Australia. bridgetw@chw.edu.au
D004734:Energy Metabolism / Q000235:genetics; D005227:Fatty Acids / Q000378:metabolism*; D005838:Genotype; D006801:Humans; D008052:Lipid Metabolism, Inborn Errors / Q000175:diagnosis / Q000201:enzymology / Q000235:genetics / Q000401:mortality / Q000628:therapy*; D008928:Mitochondria / Q000201:enzymology*; D028361:Mitochondrial Diseases / Q000175:diagnosis / Q000201:enzymology / Q000235:genetics / Q000401:mortality / Q000628:therapy*; D010084:Oxidation-Reduction; D010641:Phenotype; D013997:Time Factors; D016896:Treatment Outcome
D005227:Fatty Acids