Lipoid proteinosis was diagnosed in two daughters of a consanguinous marriage on the basis of genetic, clinical, light microscopic and ultrastructural findings. Hyaline material accumulation, thickening of the basal laminae and the resulting typical onion skin phenomenon were observed. In addition to the pathognomonic cutaneous mucosal findings, unusual manifestations such as persistence of deciduous teeth (in one case), oligodontia and intracerebral calcifications were observed. In one patient, the intracerebral calcifications caused epileptic seizures.