Outcome of medium chain acyl-CoA dehydrogenase deficiency after diagnosis

Background-Medium chain acyl-CoA dehydrogenase (MCAD) deficiency is the mos t common inborn error of fatty acid metabolism. Undiagnosed, it has a morta lity rate of 20-25%. Neonatal screening for the disorder is now possible bu t it is not known whether this would alter the prognosis. Objective-To investigate the outcome of MCAD deficiency after the diagnosis has been established. Method-All patients with a proved diagnosis of MCAD deficiency attending one centre in a four year period were reviewed. Results-Forty one patients were identified. Follow up was for a median of 6 .7 years (range, 9 months to 14 years). Nearly half of the patients were ad mitted to hospital with symptoms characteristic of MCAD deficiency before t he correct diagnosis was made. After diagnosis, two patients were admitted to hospital with severe encephalopathy but there were no additional deaths or appreciable morbidity. There was a high incidence (about one fifth) of p revious sibling deaths among the cohort. Conclusions-Undiagnosed, MCAD deficiency results in considerable mortality and morbidity. However, current management improves outcome, supporting the view that the disorder should be included in newborn screening programmes.