A case of pseudo-Zellweger syndrome with a possible bifunctional enzyme deficiency but detectable enzyme protein: Comparison of two cases of Zellweger syndrome

Three infants with peroxisomal disorders were investigated clinicobiochemically and neuroradiologically. Two had classical Zellweger syndrome, and cranial CT scans showed typical disproportionate enlargement of the occipital horns of the lateral ventricles (colpocephaly) with marked hypodensity of the white matter. In one female infant, although the clinical findings were similar to those in Zellweger syndrome, some findings, such as elevated transaminase levels, liver fibrosis, the absence of renal cortical cysts and colpocephaly, were negative or milder. Biochemical analyses revealed increased very long-chain fatty acids, dicar☐ylic aciduria and impaired β-oxidation of lignoceric acid. However, peroxisomes were abundantly present in hepatocytes and cultured fibroblasts, and all peroxisomal β-oxidation enzyme proteins were detected on immunoblot analysis. A cell fusion study suggested that the enzyme responsible for this case of ‘pseudo-Zellweger syndrome’ is bifunctional.