Complementation Analysis of Patients with Intact Peroxisomes and Impaired Peroxisomal β-Oxidation

Complementation analysis, using peroxisomal β-oxidation of very long chain fatty acids (VLCFA) as the criterion for complementation, is useful in the study of patients who are suspected of having a single enzyme defect in the peroxisomal β-oxidation pathway. Laboratory findings for these patients include elevated plasma VLCFA and impaired VLCFA oxidation in fibroblasts. Some of these patients have slightly abnormal phytanic acid oxidation in fibroblasts. In addition, elevated levels of bile acid intermediates have been reported in some cases. Plasmalogen synthesis, pipecolic acid levels, and subcellular distribution of catalase are normal. Using complementation analysis, we show that six patients. who were suspected of having a single enzyme defect in the peroxisomal β-oxidation pathway, are deficient in peroxisomal bifunctional enzyme [enoyl-CoA hydratase (EC 4.2.1. 17)/3-hydroxyacyl-CoA dehydrogenase (EC 1.1.1.35)] activity. This group of six patients, deficient in bifunctional enzyme activity, may be subdivided into two complementation groups. It would appear that patients in each of these two groups are deficient in only one of the bifunctional enzyme activities.