Semi-late onset and rapidly progressive case of Lafora's disease with predominant cognitive symptoms

The authors report a sporadic case of Lafora's disease, unusual for the comparatively late age at onset and atypical evolution. Discrete visual phenomena that may be considered as partial seizures occurred at age 19 years. A generalized tonic-clonic seizure occurred at 20 years of age and myoclonus became apparent a few weeks later. A massive cognitive dysfunction was clearly apparent 3 months after the first seizure and further mental deterioration occurred although seizures were controlled by medication and myoclonus remained minimal. The EEG showed the typical association of generalized and focal (occipital) changes. Axillary++ skin and muscle biopsies were positive and easily confirmed the diagnosis. The clinical presentation of Lafora's disease is considered by the authors to be sufficient for a clinical diagnosis, even in such an atypical case. Confirmation by skin biopsy is easily obtainable.