Methylmalonic acidemia is a rare genetic disorder that affects the body's ability to break down certain proteins and fats. This condition is caused by a deficiency of an enzyme called methylmalonyl-CoA mutase, which is essential for processing a substance called methylmalonic acid. When this enzyme is lacking, methylmalonic acid accumulates in the body, leading to various health issues. Symptoms of methylmalonic acidemia can include vomiting, dehydration, developmental delays, and metabolic crises. Early diagnosis and treatment are crucial to manage the condition effectively. Treatment may involve dietary changes, vitamin B12 supplementation, and in some cases, more advanced therapies like organ transplantation.