GFAP and Alexander disease: The reasons why we chose Alexander disease are as follows: 1, The majority of cases of Alexander disease are caused by a genetic mutation of the GFAP gene [3]; 2, There are a manageable number of reported Alexander disease cases (less than 1,000); 3, There is a diversity in the age of onset, severity, and combination of symptoms; 4, There is an established feature-based disease classification for Alexander disease; and 5, Genotype-phenotype correlations have been examined [4].