Clinical characteristics of a chromosome 17-linked rapidly progressive familial frontotemporal dementia

Objective: To describe symptoms, signs, neuroimaging results, and neuropathologic findings in patients from a family with chromosome 17q21-linked autosomal dominant frontotemporal dementia. Design: Multiple case report with genetic investigations. Subjects: The disease was observed in a Swedish family and documented in 3 generations. Four siblings are described in this article. Results: A rapidly progressive dementia with genetic linkage to chromosome 17q21 was observed, The mean age of onset was 51 years and the average duration of disease to death was 3 years, Two patients started with speech disturbances leading to a progressive, nonfluent aphasia, 1 patient had onset symptoms of leg apraxia and akinesia and muscular rigidity, and in 1 patient reckless driving was the first symptom. Loss of spontaneous speech developed later in all patients and emotional bluntness in 3 of the patients. Cerebral perfusion was decreased in the frontal areas in all patients. In the person with apraxia as the onset symptom, the cerebral blood flow was also diminished in the left hemisphere, where a slight atrophy was detected on magnetic resonance imaging scans. At the postmortem examination, slight gliosis of the parietal lobes was observed in this patient. In all patients there was a frontocentral degeneration of the cortex with discrete microvacuolation and gliosis. Conclusion: Clinical features of frontotemporal dementia, parkinsonism, an early age of onset, a rapid disease progression, and variable onset symptoms were seen in these patients. Two other clinically distinct diseases, dementia with pallido-ponto-nigral degeneration and a disinhibition-dementia-parkinsonism-amyotrophy complex, have recently been mapped to chromsome 17q21. In the family described in this article, genetic linkage was detected to the same region, suggesting the possibility that these diseases may originate from pathogenic mutations in the same gene.