Elise's Corner

About AXD

ABOUT AXD

Alexander disease, a Leukodystrophy, is a progressive and fatal neurological disorder that involves the destruction of myelin sheaths.

Myelin is a fatty coating in the brain that protects nerve fibers and helps conduct nerve impulses.

LACK OF MYELIN LEADS TO
IMPAIRMENT OF THE NERVOUS SYSTEM

CLASSIFICATION

The most recent classification system identifies two categories, TYPE I and TYPE II, with the distinction hinging more on distribution of lesions and clinical presentation, rather than age of onset as used previously.

Type I

TYPE I patients typically experience seizures and/or developmental delays affecting both cognitive and motor functions, followed by loss of milestones, and an abnormal increase in head size.

Type II

TYPE II patients frequently experience difficulty swallowing and speaking, and have poor coordination or gait. Problems with temperature control, sweating, constipation, and pain also occur.

CHROMOSOME

17

Greater than 90% of patients with Alexander disease have a mutation on chromosome 17 in the gene for glial fibrillary acidic protein (GFAP).

GFAP is a filamentous protein of astrocytes and also accumulates as part of the Rosenthal fibers. Most of the GFAP mutations result in the alteration of a single amino acid out of the total length of 432 amino acids.