Breath test for methylmalonic acidemia developedMay 8, 2021
Irini Manoli et al have developed a breath test that could evaluate how well patients with methylmalonic acidemia (MMA) respond to receiving liver or combined liver and kidney transplantation. MMA is usually caused by a deficiency of the enzyme methylmalonyl-CoA mutase (MMUT) which is essential in metabolism. MMUT protein help break down food. releasing a chemical by-product called propionate, which is followed by oxidation resulting in the release of carbon dioxide which is exhaled out. The team found that since MMUT protein is compromised in MMA patients, measuring the exhaled carbon dioxide could non-invasively help evaluate the efficiency of treatment in these patients. As carbon 12 is the commonly exhaled form of carbon and is also a by-product of several metabolic processes, the researchers gave patients a dose of less abundant carbon 13 through a food additive. The team noted that the breath samples of MMA patients with certain subtypes of the disorder had lower levels of carbon 13 than healthy volunteers. MMA patients with liver transplants had higher propionate oxidative capacity and hence higher levels of carbon 13, similar to the healthy participants. The results demonstrated that measuring propionate oxidative capacity with the new 13C-propionate breath test could predict disease severity and clinical outcomes.
Source: Genetics in Medicine (2021) | 05 April 2021| https://www.nature.com/articles/s41436-021-01143-8