The cytosolic inclusion bodies that consist of splice variants that lack exon 5 of the presenilin-2 gene differ obviously from Hirano bodies observed in the brain from sporadic cases of Alzheimer's disease patients.

Alzheimer's disease (AD) is a neurodegenerative disorder having several pathological characteristics, namely senile plaques and neurofibrillary tangles. Further, Hirano bodies (HBs), which are stained by hematoxylin-eosin, are also observed in the AD brain. Recently, we reported that an alternative splice variant that lacked exon 5 of the presenilin-2 (PS2) gene (PS2V) was expressed in sporadic AD (SAD) brains, and the PS2V-encoding proteins actually existed in these brains. Furthermore, electron microscopic experiments demonstrated that the PS2V proteins form cytosolic inclusion bodies in the pyramidal cells. In this report, we found that the PS2V-composed inclusion bodies differed obviously from the HBs. This observation suggests the possibility that PS2V-composed inclusions are a novel inclusion body, compared with other pathological characteristics previously reported in the SAD brain. We named this inclusion body the 'PS2V body'.