methylmalonic acidemia
Pronunciation: meth-uhl-mal-ON-ik as-i-DEE-mee-uh
A group of inherited metabolic disorders affecting the breakdown of certain proteins and fats, detectable through newborn screening via elevated methylmalonic acid levels.
Full Definition
Methylmalonic acidemia (MMA) represents a collection of autosomal recessive disorders caused by defects in methylmalonyl-CoA mutase enzyme or its cofactor metabolism. Affected infants cannot properly process certain amino acids (methionine, threonine, valine, isoleucine) and odd-chain fatty acids, leading to toxic accumulation of methylmalonic acid. The condition is detected in newborn screening through tandem mass spectrometry analysis of dried blood spots, typically showing elevated propionylcarnitine (C3) and methylmalonic acid levels. Early detection through screening programs is crucial as untreated MMA can lead to metabolic acidosis, developmental delays, and potentially fatal metabolic crises. Treatment involves protein restriction, carnitine supplementation, and in some cases vitamin B12 therapy depending on the specific subtype.
Usage
Usage note: Often abbreviated as MMA in clinical contexts; distinguish from other organic acidemias by specific metabolite pattern.
In Context
- "The laboratory reported elevated C3-acylcarnitine levels, prompting immediate follow-up testing to rule out methylmalonic acidemia." — Screening laboratory report
- "Confirmatory testing for methylmalonic acidemia requires quantitative measurement of methylmalonic acid in urine or plasma." — Clinical protocol documentation