Hallervorden-Spatz Disease
Incidence
It is an autosomal recessive hereditary disorder of unknown etiology. More than 100 cases has been reported.
Clinical Characteristics
It is characterized by complicated clinical symptoms comprising progressive extrapyramidal signs and usually dementia. There is partial destruction of the pallidonigral region associated with pigmentary deposits of iron and diffuse axonal swelling or spheroids. The MRI is particularly helpful in revealing typical abnormalities in the globus pallidus. The first sign may develop at any age between two and fifteen years but occasionally may be delayed until adult life. In more than 50 % of the cases the disease is apparent by the age of ten years and in eighty percent of the cases by fifteen years. Usually the initial manifestations are progressive disorder of locomotion and involuntary movements of extrapyramidal type. Dystonic posture, choreoatetoid movements (present at least in 50% of cases) and rigidity are the main findings. Each of these can be the original or predominant sign. Onset with dystonia is usual in childhood and parkinsonian rigidity is more often the main feature in older patients. Dysarthria appears early in the disease. Oromandibular involvement is prominent. Tremor may occur but not prominent. Most patients show signs of corticospinal involvement and few patients show progressive spastic paraplegia as initial symptom. Seizures are rare. EEG generally is normal. Progressive intellectual deterioration becomes evident in all cases and some children may have been mentally retarded since childhood. A few patients may have normal intelligence. 1/3 of patients have pigmentary degeneration of the retina and other patients may have optic atrophy. CT scan may either show hyper or hypointense signal in the pallidum. MRI studies reveal remarkable picture on T2 weight imaging showing pronounced bilateral hypodensity of the globus pallidus due to iron accumulation and in typical cases, a central high signal area of necrosis, producing the "tiger eye" sign. The condition is relentlessly progressive and most patients die in the second or third decade. No specific biochemical test is available for diagnosis. CSF is normal. Iron levels in blood and urine is normal. MRI gives a very important diagnostic lead. No effective treatment is available, but symptomatic treatment should be tried for parkinsonian symptoms, dystonic posturing and drooling.
Precipitants
no
Provocation Tests
no
Diagnostic Procedures
MRI gives a very important diagnostic lead. No specific biochemical test is available for diagnosis.