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Cognitive decline in a patient with anti-glutamic acid decarboxylase autoimmunity; case report

Masahito Takagi1*, Hiroshi Yamasaki1, Keiko Endo1, Tetsuya Yamada2, Keizo Kaneko2, Yoshitomo Oka2 and Etsuro Mori1

Author Affiliations

1 Department of Behavioral Neurology and Cognitive Neuroscience, Tohoku University Graduate School of Medicine, Sendai, Miyagi, 980-8574, Japan

2 Division of Molecular Metabolism and Diabetes, Tohoku University Graduate School of Medicine, Sendai, Miyagi, 980-8574, Japan

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BMC Neurology 2011, 11:156  doi:10.1186/1471-2377-11-156

Published: 21 December 2011



Glutamic acid decarboxylase (GAD) is the rate-limiting enzyme for producing γ-aminobutyric acid, and it has been suggested that antibodies against GAD play a role in neurological conditions and type 1 diabetes. However, it is not known whether dementia appears as the sole neurological manifestation associated with anti-GAD antibodies in the central nervous system.

Case presentation

We describe the clinical, neuropsychological, and neuroradiological findings of a 73-year-old female with cognitive dysfunction and type 1A diabetes. Observation and neuropsychological studies revealed linguistic problems, short-term memory disturbance, and frontal dysfunction. MRI showed no significant lesion except for confluent small T2-hyperintensity areas localized in the left basal ganglia. 18F-fluorodeoxy glucose-positron emission tomography (FDG-PET) and 123I-N-isopropyl-p-iodoamphetamine-single photon emission computed tomography (IMP-SPECT) studies showed bifrontal hypometabolism and hypoperfusion. Immunomodulating therapy with intravenous high-dose immunoglobulin resulted in no remission of the cognitive symptoms.


Cognitive dysfunction may develop as an isolated neurological manifestation in association with type 1A diabetes and anti-GAD autoimmunity. A systematic study with extensive neuropsychological assessment is indicated in patients with type 1 diabetes and anti-GAD autoimmunity.

anti-glutamic acid decarboxylase antibodies; stiff person syndrome; cognitive decline; frontal dysfunction; working memory