[P1-181] Alexander disease: case report of a rare neurodegenerative disorder
Alexander disease is a rare neurodegenerative disorder, characterized as an astrocyte disorder as the primary culprit. We present the clinical course of a case of juvenile-onset type. To date, there had not been any locally published case of the disorder in Hong Kong. A nine-years-old boy presented with progressive motor disturbance and dizziness for one week. He had also complained dizziness that is poorly characterized, however, related to postural change. No convulsion was noted ever. Physical examination showed no macrocephaly, but generalized hypertonia with hyperreflexia and extensor plantar responses. There was bilateral sustained ankle clonus. Subtle gait disturbance with unsteadiness was exacerbated on tandem walk. CT and MRI brain showed bilateral basal ganglia lesions. Electroencephalogram was normal with no epileptiform discharge. He was tested to have heterozygous missense mutation of the Glial Fibrillary Acidic Protein (GFAP) on chromosome 17q21: a confirmed diagnosis of Alexander disease. The mutation NM_002055.4 (GFAP):c.205G>A (p.Glu69Lys) was noted detected in both parents, suggestive of a de novo mutation. Case report with the same mutation had been reported in the literature with a drastically different presentation. Our case report illustrated the different presentations of the rare disorder in children and added new knowledge to the genotypic-phenotypical correlation of the disease.