This title refers to a group of hereditary disorders in which an enzyme dysfunction leads to an accumulation of iron in certain brain centers regulating movement and higher functioning. The onset of disease may be in infancy in one type but later in others.
Symptoms in the most common form of this disease first impact walking and locomotion. Fine coordination becomes difficult and there are often fine tremors or writing movements in the fingers and hands. Psychomotor delays are common among those with early onset and mental retardation has been described. Stuttering, difficulty swallowing, rigid muscles, speech impairment and jerky movements are common. The disease is relentlessly progressive and older individuals may exhibit dementia and have difficulty ambulating. Seizures are uncommon.
The optic nerve that carries visual message from the eye to the brain often becomes damaged. This together with degeneration of the retina lead to visual impairment in many individuals and often nystagmus (to-and-fro eye movements).
These iron deposition conditions are inherited in autosomal recessive patterns in which two mutations are required for the disease to be manifest. Carrier parents with only one mutation do not have disease but they can anticipate that one in four of their children will inherit both mutations.
Onset may become evident in the first two decades of life but some individuals are symptomatic in early childhood. The symptoms progressively become worse and death may occur within one or two decades after onset. Pediatricians and neurologists often collaborate on the diagnosis and MRIs of the brain are helpful. There is no effective treatment beyond supportive care.