In contrast, the adult form of the disease has been rarely described, and the etiology of this variant remains unknown. A neurological examination was performed on all affected members of this family. Most of these patients also underwent magnetic resonance imaging of the brain and a polysomnographic study. The diagnosis was confirmed pathologically in 2 individuals. We screened all coding regions of the GFAP gene in affected individuals by means of direct sequencing and single-stranded conformational polymorphisms analysis.
This mutation was not detected in more than control subjects. Clinical and radiological features of affected individuals were clearly different from those of patients with the infantile and juvenile forms of the disease. The most consistent finding was the presence of bulbar signs. In addition, sleep disturbance mainly sleep apnea , symptoms of dysautonomia, and dysmorphism were found in all affected individuals.
In younger patients, magnetic resonance imaging showed T2 signal abnormalities in the medulla compatible with an area of demyelination. In contrast, in older patients, we found marked atrophy of the medulla without signal abnormalities. None of the affected individuals exhibit signs of demyelination of the cerebral white matter. Clinical evaluation in individuals carrying mutation in the GFAP gene allowed a better definition of this heterogeneous clinical syndrome and will help increase its recognition in neurological practice.
Magnetic resonance imaging MRI of the brain in patients with Alexander disease typically shows signal abnormalities in the cerebral white matter, predominating in frontal regions. Infantile and juvenile forms of Alexander disease are generally sporadic, but a few sibling cases have been reported.
Based on the presence of Rosenthal fibers found in brain autopsy, an adult variant of Alexander disease has been reported. The evolution is protracted, and some patients may remain asymptomatic. Although Alexander disease with adult onset seems to be sporadic in most cases, familial segregation, suggesting an autosomal dominant mode of transmission, has been reported.
