Background: Alzheimer's disease (AD) and frontotemporal dementia (FTD) are two common forms of primary neurodegenerative dementia. Mutations in 3 genes (PSEN1, PSEN2, and APP) have been identified in patients with early-onset AD. Methods: We performed gene sequencing in PSEN1, PSEN2, and APP in 61 AD and 35 FTD Chinese patients. Amyloid load using 11C-labeled Pittsburgh compound B (11C-PIB) positron emission tomography (PET) and cerebral glucose metabolism using 18F-fludeoxyglucose PET were evaluated in patients carrying mutations. Results: We identified 1 known pathogenic PSEN1 (p.His163Arg, c.488A>G) mutation and 3 novel PSEN2 mutations in 6 patients. The novel mutation PSEN2 (p.His169Asn, c.505C>A) was identified in 1 patient with familial late-onset AD and in 1 sporadic FTD patient. The PSEN2 (p.Val214Leu, c.640G>T; p.Lys82Arg, c.245A>G) mutations were identified in 2 early-onset AD patients and 1 early-onset AD patient, respectively. Three patients with PSEN2 mutations were observed to have PIB retention on the cortex and striatum. One patient with the FTD phenotype was not observed to have PIB retention. Conclusion: PSEN2 mutations are common in the Chinese Han population with a history of AD and FTD. Pathogenic mutations or risk variants in the PSEN2 gene can influence both FTD and AD phenotypic traits and show variations in neuroimaging characterization. © 2014 S. Karger AG, Basel
Late-onset cerebellar ataxia in an adult with a novel mutation in the CLN5 gene
