Methylmalonic acidemias

Methylmalonic acidemias, also called methylmalonic acidurias, are a group of inherited metabolic disorders that impair the body's ability to properly break down certain proteins and fats, leading to a dangerous buildup of methylmalonic acid in the blood and tissues. They belong to the broader category of organic acidemias affecting branched-chain amino acid metabolism. Most forms are caused by autosomal recessive genetic mutations, though a nutritional form can arise from severe vitamin B12 deficiency. Severity and treatment depend on the specific mutation involved, and symptoms can appear anywhere from birth into adulthood, ranging from mild to fatal if undiagnosed and untreated. Reported symptoms include acidosis, cardiomyopathy, coma, dehydration, developmental delay, encephalopathy, failure to thrive, high blood ammonia, low blood sugar, kidney failure, lethargy, seizures, stroke and vomiting. The condition is classified under endocrinology and carries ICD-10 code E71.1. It affects all ethnic groups roughly equally.