The leukodystrophies are genetically determined progressive disorders that affect the brain, spinal cord and peripheral nerves. The term leukodystrophy derives from the Greek words "leuko" meaning white and referring to the white matter of the nervous system and "dystrophy" meaning imperfect growth or development." from www.ulf.org Other leukodystrophies include ALD (Adrenoleukodystrophy), Alexander's Disease, Krabbe's disease and several others.