medium chain acyl-CoA dehydrogenase deficiency (MCADD)

Last reviewed 01/2018

Medium chain acyl-CoA dehydrogenase deficiency (MCADD) is an autosomal recessive inherited metabolic disease which is a known treatable cause of sudden infant death.

MCADD is a rare inherited metabolic disease that reduces the ability to maintain a normal blood sugar during episodes of metabolic stress.

MCADD affects between one in 10,000 and one in 20,000 babies born in the UK and screening should identify around 28 cases a year in England

• MCADD results from the lack of an enzyme required to convert fat to energy.
  • complications typically arise when the affected child has long periods between meals, requiring the body to use its own fat reserves to produce energy
  • affected infants are often asymptomatic until an acute decompensation occurs, usually secondary to an intercurrent illness. There may be a history of episodes of reduced consciousness, most often before breakfast and after missing meals
    • MCADD causes no apparent symptoms at birth, but low blood sugar, seizures, brain damage, heart failure and serious illness can occur very quickly in infants who are not feeding well
    • treatment for the disorder requires close monitoring of the child to determine “safe” time periods between meals and following a strict feeding schedule
    • with early detection and monitoring, and avoidance of fasts, children diagnosed with MCADD can lead normal lives particularly as “safe” time between meals expand as they grow older

MCADD is one of the conditions that can be screened for as part of the UK blood spot screening programme:

• in February 2007 the UK Health Minister announces that all newborns will be screened for MCADD by March 2009