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Phenotypical difference of Amyloid Precursor Protein (APP) V717L mutation in Japanese family

Masao Abe1*, Naomi Sonobe1, Ryuji Fukuhara1, Yoko Mori1, Shinichiro Ochi1, Teruhisa Matsumoto1, Takaaki Mori12, Satoshi Tanimukai1 and Shu-ichi Ueno1

Author Affiliations

1 Department of Neuropsychiatry, Neuroscience, Ehime University Graduate School of Medicine, Shitsukawa, Toon-city, Ehime, 791-0295, Japan

2 Department of Molecular Probes, Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba-city, Chiba, 263-8555, Japan

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BMC Neurology 2012, 12:38  doi:10.1186/1471-2377-12-38

Published: 15 June 2012



Alzheimer’s disease (AD) is the most common form of dementia. Mutations in genes such as those encoding amyloid precursor protein (APP), presenilin 1 and presenilin 2, are responsible for early-onset familial AD.

Case presentation

In this study, we report a 275341 G > C (Val717Leu) mutation in the APP gene in a Japanese family with early onset AD by genetic screening. This mutation has previously been detected in European families. In the Japanese family we screened, the age at onset of AD was 47.1 ± 3.1 years old (n = 9; range, 42–52). The symptoms in the affected members included psychiatric vulnerability and focal signs such as pyramidal signs, epileptic seizures, and myoclonic discharges. An MR imaging study showed relatively mild atrophic changes in the bilateral hippocampus and cerebral cortices in all affected members compared with their clinical presentations.


We conclude that the clinical features of Alzheimer’s disease can be different even when caused by the same mutation in the APP gene. Further clinical and genetic studies are required to clarify the relationship between phenotypes and genotypes.