A dysmyelinating disorder of the central nervous system associated with a decrease in all myelin proteins, especially proteolipid protein. Several types are recognized: acute infantile types Synonyms: familial chronic infantile diffuse sclerosis perinatal sudanophilic leukodystrophy chronic infantile diffuse cerebral sclerosis adult-onset leukodystrophy Synonyms: late-onset type multiple sclerosis-like disorder autosomal dominant Pelizaeus-Merzbacher disease Pelizaeus-Merzbacher-like disease (PMLD) Synonym: Pelizaeus-Medrzbacher disease with normal proteolipid protein In its classical form, the disease has an onset in the first three months of life with nystagmus followed by slowly progressive psychomotor retardation, involuntary movements, ataxia, and death in the second decade of life. The chronic infantile type may begin as early as the eight day of life and is slowly progressive so that the patient may survive to middle age. The early symptoms include rotary movements of the head and eyes, which may vanish later in life, usually followed by spasticity of the legs and arms, cerebellar ataxia, dementia, and parkinsonian tremor. The adult form has its onset in the fourth or fifth decades and is marked mainly by cerebellar, autonomic, and pyramidal disorders. Urinary and rectal incontinence, orthostatic hypotension, and progressive spasticity are the main symptoms. Pelizaeus-Merzbacher-like disease is marked by symptoms characteristic of the classical form in, but with normal myelin which, however, is arranged into ball-like structures in the oligodendrocyte perikarya and terminal processes.