Which treatment is specifically indicated for Methylmalonic Acidemia if the patient is B12 responsive?

In the case of Methylmalonic Acidemia (MMA), if a patient is found to be B12 responsive, the appropriate treatment involves administering vitamin B12 injections. This response indicates that the patient's metabolic symptoms can be alleviated by supplementation of this vitamin, which plays a crucial role in the metabolic pathways affected by MMA. Vitamin B12 is essential for the proper function of certain enzymes in the body, and in B12-responsive patients, the deficiency of this vitamin impacts the conversion of certain compounds, leading to the accumulation of toxic metabolites.

Therefore, providing B12 injections helps restore the enzymatic activity, allowing for better metabolic function and managing the patient's symptoms. This treatment can lead to significant improvements in metabolic control and can help prevent the complications associated with elevated levels of methylmalonic acid in the body.

Alternative treatment options listed, such as liver transplant, high protein diet, and gene therapy, are either not specifically indicated for patients with B12 responsiveness or are more complex interventions that are not first-line treatments in this scenario.