Enfermedad de Lafora. Confirmación diagnóstica por genética molecular de un nuevo caso.

Abstract

Lafora s disease is a type of progressive myoclonic epilepsy with bad prognosis. Until now diagnosis was based on finding characteristic intracytoplasmatic polyglucosan bodies in biopsies of sweat secreting cells in the skin. Recently the gene responsible has been discovered. This permits firm diagnosis and screening of carriers. We present the case of a child diagnosed on molecular genetic studies.A 12 year old boy with a clinical history of three febrile seizures at the age of one year but no other abnormalities, presented a seizure of visual disorder with secondary generalization. There was no family history of seizures. Following a period of normality he had further seizures (clonic, visual and generalized myoclonic). The EEG showed generalized spike and wave activity, which was more marked after stimulation by light and became progressively worse. Neuroimaging studies were normal. In spite of treatment there was a progressive increase in visual and generalized myoclonic seizures together with deterioration of cognitive function and ataxia. Histological studies of the sweat glands showed homogeneous nodular deposits of intracytoplasmatic PAS+. Molecular studies of the EPM2A gene linked to chromosome 6q24 showed the presence of two mutations on the 1 and 4 exons.We describe a 12 year old patient with all the clinical features of Lafora type progressive myoclonic epilepsy in whom characteristic cytoplasmic bodies were found in the sweat gland biopsy. Molecular genetic studies of the EPM2A gene confirmed diagnosis of the disorder.