[Early diagnosis of Lafora disease. Significance of paroxysmal visual manifestations and contribution of skin biopsy].

The early diagnosis of Lafora's disease is often difficult, from primary generalized epilepsy and other progressive myoclonic epilepsies. The authors emphasize the diagnostic interest of paroxysmal visual manifestations, reported in only 25 per cent of the cases in the literature, and present in 17 of their 31 personal cases. These visual manifestations can be elementary or complex. The elementary ones appear often early, before other symptoms of the disease. Two demonstrative cases are reported. In one of them an occipital seizure was recorded, demonstrating the epileptic critical nature of these elementary visual manifestations. They have a high diagnostic value since they do not occur neither in primary generalized epilepsy (Grand Mal type), nor in the other progressive myoclonic epilepsies. In the 2 reported cases, skin biopsy, as proposed by Carpenter and Karpati, demonstrated the specific storage in the sweat ducts and glands. The interest of this skin biopsy is underlined, its positivity seeming both constant and specific in Lafora's disease.