Clinical and neuroimaging characterization of Chinese dementia patients with PSEN1 and PSEN2 mutations.

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 (11)C-labeled Pittsburgh compound B ((11)C-PIB) positron emission tomography (PET) and cerebral glucose metabolism using (18)F-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.