human and rodent brain. These isoforms include GFAP kappa, GFAP +1 and the currently best researched GFAP delta. GFAP delta appears to be linked with neural stem cells (NSCs) and may be involved in migration. GFAP+1 is an antibody which labels two isoforms. Although GFAP+1 positive astrocytes are supposedly not reactive astrocytes, they have a wide variety of morphologies including processes of up to 0.95mm (seen in the human brain). The expression of GFAP+1 positive astrocytes is linked with old age and the onset of AD pathology. See also 17q21.31 microdeletion syndrome (Koolen–de Vries syndrome) GFAP stain References Further reading External links GeneReviews/NCBI/NIH/UW entry on Alexander disease OMIM entries on Alexander disease Proteins Biology of bipolar disorder