Carnitine-acylcarnitine translocase deficiency: phenotype, residual enzyme activity and outcome

Carnitine-acylcarnitine translocase deficiency is a rare and life-threatening mitochondrial fatty acid beta-oxidation disorder. We describe a patient who, despite a severe clinical course and an extremely low carnitine-acylcarnitine translocase activity, is currently alive and in good health. We performed an extensive analysis of all previously published cases in order to evaluate the clinical features and prognostic factors. Reports on 21 patients with carnitine-acylcarnitine translocase deficiency were obtained. Only 5 out of the 21 patients survived early childhood. At least 20 siblings are reported to have died of sudden unexplained death in the neonatal period. Although phenotype and residual enzyme activity have been suggested to be related to outcome, we were not able to establish such a relationship.

Phenotype and residual enzyme activity do not appear to be major prognostic factors. Vigorous work-up in order to reach an expedite diagnosis and prompt medical intervention during acute episodes, especially in the neonatal period, may prevent fatal complications.