Imaging evidence of nigral damage in dystonia secondary to disulfiram intoxication

Galactosialidosis is an autosomal recessive lysosomal storage disorder characterized by a combined deficiency of bgalactosidase and a-neuraminidase, due to a defect of another lysosomal protein, cathepsin A. The latter, forms a complex with b-galactosidase and neuraminidase, and protects them against excessive proteolytic degradation. Three clinical phenotypes had been described: a severe early infantile form; a milder late infantile type with minor mental deterioration; and a juvenile/adult form, mainly found in Japan, which is characterized by slowly progressive neurological symptoms, skeletal and eye abnormalities, dysmorphism, angiokeratomas, and long survival. Herein, we report a case of galactosialidosis of the juvenile-adult form in a Peruvian girl with angiokeratoma corporis diffusum (ACD) and myoclonus. A 24-year-old woman presented a 5-year history of involuntary movements. At age 19, she developed a progressive myoclonic disorder that started in the lower limbs and caused frequent falls. The myoclonus subsequently spreads to other body regions. Five years into the disease, she was almost wheelchair bound, and other activities such as eating and speaking were considerably affected. There were, however, no seizures or cognitive decline. She was the third child of nonconsanguineous Peruvian parents and had two older sisters, one of which had skin lesions but no abnormal movements. There was no family history of neurological disorders. Further information about ancestor’s origins couldn’t be obtained, although some oriental features seemed to be present in distant relatives. The patient’s developmental milestones were normal and she had a history of anemia and irregular menstrual cycles. Physical examination revealed densely peppered red macules ranging from 1 to 3 mm on palms (Fig. 1), elbows, knees, oral mucosa, lips, and on thighs and loins in a bathing suit distribution. She had distal transverse reddish bands on her nails and few naevi on her soles. She was short (146 cm) and had course facial features and hypertrichosis. Neurological examination showed mild intellectual dysfunction (IQ, 68), mild sensorineural hearing impairment, and decreased visual acuity. Deep tendon reflexes were brisk. Tone and muscle strength were slightly reduced. She had multifocal, stimulus sensitive myoclonus triggered by action. She had a wide-based-bouncing gait and needed help to walk because of negative myoclonus. The laboratory tests were all normal except for a mild microcytic anemia. Cerebrospinal fluid examination (including lactate levels) and copper metabolism were normal. She had subclinical hypothyroidism but no elevated antithyroid antibodies. Serum gluten antibodies were within normal range. Ophthalmologic examination revealed myopia, mild optic atrophy, reduced visual acuity but no macular cherryred spots. The electroencephalogram was normal. Needle electromyography showed myopathic changes with normal nerve conduction velocities. Muscle biopsy was nonspecific. Median nerve somatosensory evoked potentials were enlarged (P25-N33(left/right) 1⁄4 16/20 lV), but C reflexes were absent. No visceromegaly was found on abdominal ultrasound. Brain MRI revealed no abnormalities except vermian atrophy. Basal ganglia spectroscopy was normal. Histopathological examination of skin lesions showed telangiectasias and angiokeratomas. Angiokeratomas are vascular lesions that can be found isolated in normal individuals, but when they are wide spread, the term ACD is used. ACD constitutes the dermatological hallmark of several inherited lysosomal disorders. In a Giemsa-stained peripheral blood smear, small cytoplasmic vacuoles were observed in the lymphocytes, suggesting a storage disorder. Electron microscopic examination revealed numerous cytoplasmic vacuoles with electron-lucid granular deposits in the endothelial cells of blood vessels, in pericytes (Fig. 2) and fibroblasts. The same characteristic vacuoles were found in the naevus melanocytes. Assays of enzymatic activities in leukocytes showed a marked decrease in b-