Clinical Use: Occasionally, specialized MMA testing may be ordered to help diagnose methylmalonic acidemia, a rare inherited metabolic disorder that occurs in about 1 in 50,000 to 100,000 people.
Background: Methylmalonic acid is a vital intermediate in the metabolism of fat and protein. Abnormalities in methylmalonic acid metabolism lead to an inherited disorder called methylmalonic aciduria which makes the body unable to process certain proteins and lipids properly due to a block in the enzymatic conversion of methylmalonyl CoA to succinyl CoA. There are a variety of different biochemical and clinical disturbances of methylmalonate metabolism leading to methylmalonicaciduria – at least six discrete biochemical bases for inherited forms:
2 distinct defects of MMA CoA mutase deficiency;
2 defects of adenosylcobalamin synthesis;
2 defects of adenosylcobalamin and methylcobalamin synthesis.

Babies with this disease are unable to convert methylmalonyl CoA to succinyl CoA. They appear normal at birth but as they ingest protein, they begin to show symptoms such as seizures, failure to thrive, mental retardation, strokes, and severe metabolic acidosis. Many newborn screening programs are now testing for this disorder.

Occasionally, specialized MMA testing may be ordered when a doctor suspects that an acutely ill infant may have inherited methylmalonic acidemia. MMA testing may also be performed as part of an infant’s newborn screening.

Reference Ranges:
Associated Diseases:
Patient Preparation: None required
Specimen Requirements: Random Urine – Plain urine container
Turnaround Time: 4 weeks
Additional Information:
Referred Test: Referred test
Location: Paediatric Metabolic Centre