A Prospective, Longitudinal, Observational, Multi-centre Study of Pediatric Participants up to 16 Years of Age With Methylmalonyl-CoA Mutase Deficiency Caused by Mutations in the MMUT Gene That Results in a Diagnosis of Isolated Methylmalonic Acidemia (MMA).
Methylmalonic Acidemia (MMA) is a severe and rare condition that affects how the body turns food into energy. In people with MMA, the body is missing or has a very low activity of a specific protein (an enzyme called methylmalonyl-CoA mutase (MMUT)) needed to break down certain proteins and fats in everyday food. Because this process does not work properly, a harmful substance called methylmalonic acid builds up in the blood and tissues, causing damage in the body. Most people with MMA have an altered MMUT gene, which affects the enzyme methylmalonyl-CoA mutase. MMA often appears in infancy or early childhood, but some people are diagnosed later. MMA affects approximately 1 in every 100,000 babies born and primarily impacts the liver, brain and kidneys. MMA poses significant challenges as it can result in complications such as dangerous acid levels in the blood, problems with the brain and nerves, visions problems, problems with how the pancreas, liver, and the kidneys work, as well as growth and development delays. The main purpose of this observational study that tracks how the disease develops over time is to gather necessary data and evidence to confirm which signs in the body and blood test results can reliably show disease activity related to MMA. These confirmed signs and blood test results will be used for future research into developing new treatments for MMA. The data will be collected from participants with severe symptoms with and without liver transplant.
⁃ Aged ≤16 years at screening visit
⁃ With or without previous liver (or combined liver/kidney) transplantation at time of screening (note: number of transplanted participants capped at n=15) 3. Confirmed laboratory diagnosis of Isolated MMA caused by mutations in the MMUT gene (NOTE: if a historical genetic mutational analysis report was available at Screening visit but was not from a CLIA/ISO15189 approved laboratory, a confirmatory sample will be taken during the study. However the original lab report will be adequate for study eligibility consideration)..
• 4\. Severe MMA phenotype.
• For untransplanted participants, all of the following criteria (a-c) must be met to qualify as severe MMA phenotype:
∙ Serum methylmalonic acid (sMMA) level of \>100 µmol/L at the Screening visit
‣ An unscheduled ER visit, hospitalization or requirement for use of the sick day diet regimen in the 12 months prior to the screening visit
‣ Considered to potentially require future liver transplantation to improve metabolic stability in accordance with MMA transplantation guidelines (Baumgartner 2014, Forny 2021, Sen 2023)
• For participants with previous liver or combined liver and kidney transplantation, the phenotype of the participant will be judged by the Investigator to be severe if both of the following were applicable prior to transplantation:
∙ Pre-transplant serum methylmalonic acid (sMMA) level of \>100 µmol/L AND
‣ Transplantation was conducted to improve metabolic stability in accordance with MMA transplantation guidelines (Baumgartner 2014, Forny 2021, Sen 2023).
• NOTE: sMMA pre-transplant measure must have been obtained within 6 months prior to transplant. An alternative blood MMA concentration may be used (e.g. plasma MMA, or dry blood spot), if sMMA is unavailable. Details of the assay used must be provided and additional samples will be collected during the study to allow comparison to sMMA results.