Alexander's Disease, an Autosomal Dominant Disorder

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  • Topic: Myelin, Leukodystrophy, Adrenoleukodystrophy
  • Pages : 4 (1109 words )
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  • Published : October 5, 2008
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Alexander’s Disease was first described in 1949, by a prominent doctor from New Zealand by the name of William Stuart Alexander (2). When it is inherited, Alexander’s Disease is an autosomal dominant disorder, however many times it is due to a missense mutation, most of which affect exons 1, 4 and 6 (5). Alexander’s Disease, also known as ALX, AxD, demyelinogenic leukodystrophy, leukodystrophy with Rosenthal fibers and various others, is in a category of diseases known as the leukodystrophies (4, 6). “Leukodystrophy” comes from the Greek roots leuko which means white, trophy, which means growth, and dys, which means ill (7). Patients who suffer from a leukodystrophy suffer from the demyelization of the axons in their brain (3). Myelin is a fatty substance that insulates the axons and helps the brain to send signals faster, it is found in the “white matter” portion of the brain (1, 7). People with diseases such as Alexander’s Disease and other leukodystrophies commonly lose most motor skills and are more or less dependent on others to keep them living.

Since its first description in 1949, there have been no more than 500 cases of Alexander’s Disease reported (1). Almost all of the patients who suffer from Alexander’s Disease are males (9). It is found that persons with Alexander’s Disease have a mutation of chromosome 17 which codes for the protein GFAP (4, 5). GFAP is glial fibrallary acidic protein (5). The mutation of the gene that codes for GFAP is thought to disturb the normal formation of regular intermediate filaments; this disturbance may cause a buildup of what is known as Rosenthal fibers which impede the duties of astrocytes, or astroglial cells (3, 4). It is not sure among the medical community, the purpose of these astroglial cells in conjunction with the myelin sheathes, but it is thought that they assist in the creation and maintenance of it and the presence of the Rosenthal fibers simply blocks or interrupts their maintenance (4, 8)....
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