Parkinsonian Phenotypes in Down Syndrome: A Potentially Reversible Cause of Parkinsonism
Audrey Blazek Ramsay1, Tina Liu2, Keith Coffman1, Rodolfo Savica1
1Mayo Clinic, 2Swedish Health Services
Objective:
To describe parkinsonian phenotypes in persons with Down Syndrome, including Down Syndrome Regression Syndrome.
Background:
Patients with Down Syndrome (DS) infrequently develop parkinsonism, often in the context of Alzheimer’s dementia, and are occasionally responsive to levodopa. Down Syndrome Regression Syndrome (DSRD) is a phenomenon that may manifest in progressive motor symptoms of parkinsonism or catatonia, and cognitive decline.
Design/Methods:
We identified patients with DS exhibiting parkinsonian symptoms, excluding those with a suspected etiology of neuroleptic exposure (n=14). We recorded description of parkinsonian phenotype, age of onset, severity using the Unified Parkinson’s Disease Rating Scale (UPDRS) part III, diagnostic testing, and levodopa or other treatment response when available.
Results:
Patients with typical parkinsonism (n=6) were older, mean age 56.5±10.9, demonstrated more mild symptoms, median UPDRS part III 18.0(7.0), and were responsive to levodopa (n=4). Three of the six patients had associated cognitive decline interpreted as underlying Alzheimer’s pathology. Patients with suspected DSRD (n=4) were younger, mean age 24.0±7.8, demonstrated more severe symptoms, median UPDRS part III 34.0(4.5), and were not levodopa-responsive (n=2). Four patients exhibited predominant gait freezing with minimal to no other parkinsonism and no evidence of levodopa trial.
Three of four patients with suspected DRSD were treated with intravenous immunoglobulin ranging from 1.5 to 2 g/kg and achieved resolution of parkinsonism. One patient had improvement with daily lorazepam. There were no abnormalities on DaTscan (n=2). One patient demonstrated significant mineralization in the basal ganglia on CT. Cerebrospinal fluid (CSF) was non-inflammatory (n=3). Serum showed elevated thyroid peroxidase antibodies in one patient. All autoimmune panels in serum (n=3) and CSF (n=3) were non-contributory.
Conclusions:
Parkinsonism in DS may present with variable features and can be due to multiple causes. DSRD represents a potentially reversible parkinsonism, possibly of autoimmune etiology. Further studies including CSF analysis are needed to investigate pathogenesis.
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