[Morphological study on biopsied skin materials of Lafora disease].

Skin biopsy of a patient with Lafora disease was performed. The specimen showed numerous PAS-positive materials in the eccrine glands as proposed by Carpenter and Karpati. The patient was a 25-year-old man, and his two brothers and sister were diagnosed as Lafora disease by clinical and autopsy findings. The patient has shown typical clinical course of Lafora disease. Light microscopic findings of the skin revealed 5-7 microns oval or round PAS-positive materials in most of the glandular cells in eccrine glands. Several histochemical stainings were applied to the specimens so that the storage materials in the glandular cells were considered as glucose-polymer (polyglucosan). Electronmicroscopic observation showed the materials adjacent to the nucleus without limiting membrane. The materials were composed of numerous glycogen-like particles associated with a small number of fine filaments and vesicles. It have been not clarified why these materials are present in the sweat glands in Lafora disease. Recently skin biopsies have been underwent in patients of storage disease involving the central nervous system. Especially it is much useful for diagnosis of the disease with no reliable enzymatic assays. Pathogenesis of Lafora disease is still unknown. Therefore, skin biopsy might be convenient to differentiate from other types of myoclonus epilepsy.