Recent clinical and biochemical studies have revealed the existence of a ‘peroxisomal disorder’ originating in dysfunction of peroxisomes. In spite of intensive studies, the primary lesion of Zellweger syndrome is obscure (Aikawa et al., 1987). Johan et al. (1986) reported peroxisomal dysfunction in a boy with neurological symptoms and amaurosis. In the patient’s liver, electron microscopy did not show organelles that looked like peroxisomes in appearance and number. We report here four cases of Leber disease and the heterogeneity among them.