Methylmalonic Acidaemia/Propionic Acidaemia (MMA/PA)

The ‘building blocks’ of protein are called amino acids. In Methylmalonic acidaemia (MMA) and Propionic acidaemia (PA), due to a lack of specific enzymes, the body cannot properly deal with four of the amino acids, methionine, threonine , valine  and isoleucine . People with MMA or PA therefore need to restrict the amount of protein they eat.

The management of MMA or PA may involve the use of protein substitutes. Protein substitutes for MMA or PA provide all the amino acids found in protein but no methionine, threonine or valine and only a small quantity of isoleucine. As such, they provide a source of protein that is free from, or low in, the amino acids that cause problems in MMA and PA.  If used, protein substitutes are used alongside the individual’s allowance of regular dietary protein.