Carnitine transport defect presenting with hyperammonemia: report of one case.

Carnitine (beta-hydroxy-gamma-trimethylaminobutyric acid) is involved in the transport of long-chain fatty acids into the mitochondrial matrix and removal of potentially toxic acylcarnitine esters. Carnitine transport defect is a very rare metabolic disease. A 7-month-old female infant was found to have consciousness disturbance, hyperammonemia, hepatomegaly and elevated transaminases. Both the concentrations of free carnitine and acylcarnitines in her blood were very low. The diagnosis of carnitine transport defect was confirmed by assays of carnitine uptake and transport in skin fibroblasts. She responded dramatically to carnitine therapy, and there was no hyperammonemia attack for more than 3 years. Her cardiac function also remained normal.