Genetic testing
CONFIRMATION OF DIAGNOSIS
CONFIRMATION OF DIAGNOSIS
Genetic testing for pathogenic variants in glial fibrillary acidic protein (GFAP) is used to confirm an Alexander disease diagnosis and can rule out competing diagnoses. Approximately 95% of Alexander disease cases are associated with a pathogenic variant in GFAP in the region of chromosome 17q21.1,20 Pathogenic variants of GFAP exhibit an autosomal dominant pattern of inheritance, and while the majority of cases are the result of de novo mutations, familial cases are being increasingly recognized as diagnosis has improved.24
![DNA sequences appear under a Petri dish with a syringe in the middle. [69]](/sites/default/files/2025-06/Mask%20Group%2027%20%281%29.png)
Molecular genetic testing for Alexander disease can include a combination of gene-targeted testing (single-gene testing and multigene panel) and comprehensive genomic testing (exome sequencing, genome sequencing) depending on the phenotype.23
Genetic Counseling
Genetic counseling is an essential part of the genetic testing process. A genetic counselor can explain the inheritance pattern of Alexander disease, help families understand the implications of the test results, and provide support and resources to affected individuals and their families.23
Disease management
Obtaining a definitive Alexander disease diagnosis often represents a major milestone in the affected person’s clinical journey and may inform disease management options.13,17