For which condition is biotin supplementation indicated as treatment?

Biotin supplementation is indicated in the treatment of multiple carboxylase deficiency. This condition is a metabolic disorder caused by a deficiency of biotin-dependent carboxylases, which are enzymes involved in important metabolic pathways including fatty acid synthesis and amino acid catabolism. The lack of biotin leads to an accumulation of organic acids in the body, which can cause a variety of symptoms such as developmental delays, skin rashes, and hair loss.

Supplementing with biotin helps to restore the activity of these enzymes, thereby mitigating the effects of the deficiency. This is particularly effective because biotin acts as a cofactor for several carboxylases, and providing it supplements the body's need to manage metabolic functions effectively.

In contrast, the other conditions listed do not have the same relationship with biotin. For example, homocystinuria is related to defects in methionine metabolism and usually requires treatment with other vitamins such as pyridoxine or supplementation with betaine, rather than biotin. Methylmalonic acidemia is associated with a deficiency of the enzyme methylmalonyl-CoA mutase or a defect in vitamin B12 metabolism, thus requiring vitamin B12 therapy. Isovaleric acidemia, related to the metabolism