RESUMO
Alexander disease(AD) is a rare fatal demyelinating disorder, caused by the mutation of glial fibrillary acidic protein(GFAP) gene. It is characterized by progressive demyelination of central nervous system, and the accumulation of Rosenthal fibers within astrocytes. It is divided into three group: infantile, juvenile, and adult. The infantile type is most common, has onset during the first 2 years of life. It shows macrocephaly and psychomotor delay, spastic paraparesis, seizure, and feeding problems, and usually dies within the first decade. The severity of the pathological changes depend on the age of onset. Radiological study revealed white matter loss, usually with frontal predominance. It is diagnosed by DNA analysis. We present case of a 10-month-old male patient with AD. He had focal seizures, demyelination in the frontal lobe in MRI, and the presence of a K86E mutaion in the GFAP gene, involving the replacement of adenosine with guanine.