Large-scale APP duplication in early-onset Alzheimer's disease without cerebral amyloid angiopathy: A case report

Sho Shimohama; Shumpei Azami; Munenori Oyama; Tsubasa Takizawa; Masahito Kubota; Hisato Suzuki; Mamiko Yamada; Jin Nakahara; Daisuke Ito

doi:10.1177/25424823251412896

Large-scale APP duplication in early-onset Alzheimer's disease without cerebral amyloid angiopathy: A case report

Sho Shimohama
, Shumpei Azami
, Munenori Oyama
, Tsubasa Takizawa
, Masahito Kubota
, Hisato Suzuki
, Mamiko Yamada
, Jin Nakahara
, Daisuke Ito

Department of Internal Medicine (Neurology)

Research output: Contribution to journal › Article › peer-review

Abstract

We present the case of a patient who began experiencing cognitive decline in her 30 s and was diagnosed with duplication of the amyloid precursor protein (Dup-APP) associated early-onset Alzheimer's disease (EOAD). The diagnosis was supported by the presence of amyloid and tau biomarkers. The clinical course, neuroimaging findings, and genetic testing excluded other diseases known to cause early-onset cognitive impairment. Our case exhibited a markedly large duplication of 19 Mb and did not present with cerebral amyloid angiopathy. Our findings suggest a potential association between the size of the duplication and the clinical phenotype.

Original language	English
Journal	Journal of Alzheimer's Disease Reports
Volume	10
DOIs	https://doi.org/10.1177/25424823251412896
Publication status	Published - 2026 Jan 1

UN SDGs

This output contributes to the following UN Sustainable Development Goals (SDGs)

SDG 3 Good Health and Well-being

Keywords

Alzheimer's disease
Down syndrome
amyloid β-protein precursor
biomarkers
dementia
tau

ASJC Scopus subject areas

General Neuroscience
Clinical Psychology
Geriatrics and Gerontology
Psychiatry and Mental health

Access to Document

10.1177/25424823251412896

Cite this

@article{4774532e362440ea93d820d8ed8f3869,

title = "Large-scale APP duplication in early-onset Alzheimer's disease without cerebral amyloid angiopathy: A case report",

abstract = "We present the case of a patient who began experiencing cognitive decline in her 30 s and was diagnosed with duplication of the amyloid precursor protein (Dup-APP) associated early-onset Alzheimer's disease (EOAD). The diagnosis was supported by the presence of amyloid and tau biomarkers. The clinical course, neuroimaging findings, and genetic testing excluded other diseases known to cause early-onset cognitive impairment. Our case exhibited a markedly large duplication of 19 Mb and did not present with cerebral amyloid angiopathy. Our findings suggest a potential association between the size of the duplication and the clinical phenotype.",

keywords = "Alzheimer's disease, Down syndrome, amyloid β-protein precursor, biomarkers, dementia, tau",

author = "Sho Shimohama and Shumpei Azami and Munenori Oyama and Tsubasa Takizawa and Masahito Kubota and Hisato Suzuki and Mamiko Yamada and Jin Nakahara and Daisuke Ito",

note = "Publisher Copyright: {\textcopyright} The Author(s) 2026. This article is distributed under the terms of the Creative Commons Attribution-NonCommercial 4.0 License (https://creativecommons.org/licenses/by-nc/4.0/) which permits non-commercial use, reproduction and distribution of the work without further permission provided the original work is attributed as specified on the SAGE and Open Access page (https://us.sagepub.com/en-us/nam/open-access-at-sage).",

year = "2026",

month = jan,

day = "1",

doi = "10.1177/25424823251412896",

language = "English",

volume = "10",

journal = "Journal of Alzheimer's Disease Reports",

issn = "2542-4823",

publisher = "SAGE Publications Ltd",

}

TY - JOUR

T1 - Large-scale APP duplication in early-onset Alzheimer's disease without cerebral amyloid angiopathy

T2 - A case report

AU - Shimohama, Sho

AU - Azami, Shumpei

AU - Oyama, Munenori

AU - Takizawa, Tsubasa

AU - Kubota, Masahito

AU - Suzuki, Hisato

AU - Yamada, Mamiko

AU - Nakahara, Jin

AU - Ito, Daisuke

N1 - Publisher Copyright: © The Author(s) 2026. This article is distributed under the terms of the Creative Commons Attribution-NonCommercial 4.0 License (https://creativecommons.org/licenses/by-nc/4.0/) which permits non-commercial use, reproduction and distribution of the work without further permission provided the original work is attributed as specified on the SAGE and Open Access page (https://us.sagepub.com/en-us/nam/open-access-at-sage).

PY - 2026/1/1

Y1 - 2026/1/1

N2 - We present the case of a patient who began experiencing cognitive decline in her 30 s and was diagnosed with duplication of the amyloid precursor protein (Dup-APP) associated early-onset Alzheimer's disease (EOAD). The diagnosis was supported by the presence of amyloid and tau biomarkers. The clinical course, neuroimaging findings, and genetic testing excluded other diseases known to cause early-onset cognitive impairment. Our case exhibited a markedly large duplication of 19 Mb and did not present with cerebral amyloid angiopathy. Our findings suggest a potential association between the size of the duplication and the clinical phenotype.

AB - We present the case of a patient who began experiencing cognitive decline in her 30 s and was diagnosed with duplication of the amyloid precursor protein (Dup-APP) associated early-onset Alzheimer's disease (EOAD). The diagnosis was supported by the presence of amyloid and tau biomarkers. The clinical course, neuroimaging findings, and genetic testing excluded other diseases known to cause early-onset cognitive impairment. Our case exhibited a markedly large duplication of 19 Mb and did not present with cerebral amyloid angiopathy. Our findings suggest a potential association between the size of the duplication and the clinical phenotype.

KW - Alzheimer's disease

KW - Down syndrome

KW - amyloid β-protein precursor

KW - biomarkers

KW - dementia

KW - tau

UR - https://www.scopus.com/pages/publications/105031074210

UR - https://www.scopus.com/pages/publications/105031074210#tab=citedBy

U2 - 10.1177/25424823251412896

DO - 10.1177/25424823251412896

M3 - Article

AN - SCOPUS:105031074210

SN - 2542-4823

VL - 10

JO - Journal of Alzheimer's Disease Reports

JF - Journal of Alzheimer's Disease Reports

ER -

Large-scale APP duplication in early-onset Alzheimer's disease without cerebral amyloid angiopathy: A case report

Abstract

UN SDGs

Keywords

ASJC Scopus subject areas

Access to Document

Other files and links

Fingerprint

Cite this