[Intolerance to exercise caused by carnitine palmitoyltransferase deficiency].

Exercise intolerance with slight myalgia worsened by a cold environment resulted in the diagnosis of CPT deficiency in a young boy with no family history. Recurrent myoglobinuria is not the hallmark of such a deficit. Biochemical examination of muscle biopsy in suggestive situations is the way to diagnosis. Concomitant myoadenylate deficiency in this patient could represent a precipitating factor. Partial CPT deficiency in all the patients reported was first explained through the mechanism of intra mitochondrial fatty acid transport but raises questions about the regulation of CPT synthesis.