Which metabolic disorder manifests with a characteristic "smelly feet" odor?

The metabolic disorder that is known for causing a characteristic "smelly feet" odor is Isovaleric Acidemia. This condition results from a deficiency in the enzyme isovaleryl-CoA dehydrogenase, which is involved in the metabolism of the amino acid leucine. When this enzyme is not functioning properly, isovaleryl-CoA accumulates in the body, and it is ultimately converted into isovaleric acid, which has a distinct odor reminiscent of sweaty or smelly feet.

This odor can serve as an important clinical clue for healthcare providers when diagnosing isovaleric acidemia, particularly in neonates or infants presenting with symptoms like lethargy or feeding difficulties. Early detection and management are crucial as the condition can lead to metabolic crises if not treated.

In contrast to Isovaleric Acidemia, Noonan Syndrome, Lesch-Nyhan Syndrome, and Costello Syndrome do not have any associated odors that are characteristic or indicative of the condition. These disorders have their own unique clinical presentations and symptoms, which are not related to the distinct odor produced by Isovaleric Acidemia.