Biochemical and molecular correlations in carnitine palmitoyltransferase II deficiency

Carnitine palmitoyltransferase II (CPT II) deficiency is the most common li pid myopathy in adults and is characterized by exercise-induced pain, stiff ness, and myoglobinuria. Retrospective analysis of patients with CPT II def iciency has made it possible to correlate the presence of disease-causing m utations in the CPT2 gene with residual CPT activity in muscle. We present evidence that the ratio of CPT II activity to citrate synthase activity in the skeletal muscle of patients presumed to have CPT II deficiency is impor tant for predicting whether the patient has one, two, or no mutations in th e CPT2 gene. This finding will assist in the future correlation of the phen otype with the genotype and in identifying manifesting heterozygotes. (C) 1 999 John Wiley & Sons, Inc.