Presenile Dementia With 'Lafora-like' Intraneuronal Inclusions

An elderly man was affected by progressive dementia, motor neuron disease, and sensory abnormalities for about three years, since the age of 59. Seizures or myoclonus were not observed. On postmortem examination, abnormal inclusion bodies which were histologically, histochemically, and ultrastructurally identical to Lafora disease, were seen in neuronal processes throughout the central nervous system (CNS). Unlike classical Lafora's disease, however, their presence was limited to neuronal processes and not in the perikarya. Also, diffuse distribution of these bodies in the CNS differed from classical Lafora's disease, which showed more heavy concentration in the dentate nucleus, thalamus, inferior olive, and substantia nigra. Since it appears that the inclusions were almost identical, the differences in localization and distribution of inclusions may contribute to the differences in symptomatology between the present case and classical cases of Lafora's disease.