Background: Medium chain acyl-CoA dehydrogenase (MCAD) deficiency is a common disorder of fatty acid oxidation in north west Europe. It is very variable in its clinical consequences and is believed to be considerably underdiagnosed.
Objective: To investigate the diagnosis and outcome of MCAD deficiency in the UK.
Method: A prospective surveillance study through the British Paediatric Surveillance Unit.
Results: Of 62 affected individuals identified, 57 were from England, giving an incidence of 4.5 cases/100,000 births. Forty six cases presented with an acute illness (10 of whom died), 13 cases were identified because of family history, and three for other reasons. Six of the survivors were neurologically impaired.
Conclusions: Despite increased clinical awareness, the mortality and morbidity from MCAD deficiency remain high. The frequency and severity of the disease support the case for the introduction of universal neonatal screening in England and Scotland.