The hallmark signs and symptoms of<unk>  include little or no movement in the arms or legs, respiratory difficulties, and characteristic horizontal movements of the eyes left to right. The onset of<unk>  is usually in early infancy. The most characteristic early signs are nystagmus (rapid, involuntary, rhythmic motion of the eyes) and low muscle tone. Motor abilities are delayed or never acquired, mostly depending upon the severity of the mutation. Most children with<unk>  learn to understand language, and usually have some speech. Other signs may include tremor, lack of coordination, involuntary movements, weakness, unsteady gait, and over time, spasticity in legs and arms. Muscle contractures often occur over time. Mental functions may deteriorate. Some patients may have convulsions and skeletal deformation, such as scoliosis, resulting from abnormal muscular stress on bones.
Pelizaeus–Merzbacher disease
Axenfeld–Rieger syndrome
Kufor–Rakeb syndrome
Zunich–Kaye syndrome
Letterer–Siwe disease
Cornelia de Lange syndrome
Sturge–Weber syndrome
Hurler–Scheie syndrome