[Serial magnetic resonance images of a Creutzfeldt-Jakob disease patient with V180I mutation obtained over 10 years]

Prion Mutations in Republic of Republic of Korea, China, and Japan

Prion gene (PRNP) mutations are associated with diverse disease phenotypes, including familiar Creutzfeldt-Jakob Disease (CJD), Gerstmann-Sträussler-Scheinker disease (GSS), and fatal familial insomnia (FFI). Interestingly, PRNP mutations have been reported in patients diagnosed with Alzheimer's disease, dementia with Lewy bodies, Parkinson's disease, and frontotemporal dementia. In this review, we describe prion mutations in Asian countries, including Republic of Republic of Korea, China, and Japan. Clinical phenotypes and imaging data related to these mutations have also been introduced in detail. Several prion mutations are specific to Asians and have rarely been reported in countries outside Asia. For example, PRNP V180I and M232R, which are rare in other countries, are frequently detected in Republic of Korea and Japan. PRNP T188K is common in China, and E200K is significantly more common among Libyan Jews in Israel. The A117V mutation has not been detected in any Asian population, although it is commonly reported among European GSS patients. In addition, V210I or octapeptide insertion is common among European CJD patients, but relatively rare among Asian patients. The reason for these differences may be geographical or ethical isolation. In terms of clinical phenotypes, V180I, P102L, and E200K present diverse clinical symptoms with disease duration, which could be due to other genetic and environmental influences. For example, rs189305274 in the ACO1 gene may be associated with neuroprotective effects in cases of V180I mutation, leading to longer disease survival. Additional neuroprotective variants may be possible in cases featuring the E200K mutation, such as KLKB1, KARS, NRXN2, LAMA3, or CYP4X1. E219K has been suggested to modify the disease course in cases featuring the P102L mutation, as it may result in the absence of prion protein-positive plaques in tissue stained with Congo red. However, these studies analyzed only a few patients and may be too preliminary. The findings need to be verified in studies with larger sample sizes or in other populations. It would be interesting to probe additional genetic factors that cause disease progression or act as neuroprotective factors. Further studies are needed on genetic modifiers working with prions and alterations from mutations.

Clinicopathological findings of a long-term survivor of V180I genetic Creutzfeldt-Jakob disease

The clinical characteristics of genetic Creutzfeldt-Jakob disease (gCJD) with a V180I mutation in the PRNP gene (V180I gCJD) are unique: elderly-onset, gradual progression, sporadic fashion, and cortical oedematous hyper-intensity on diffusion-weighted MRI (DW-MRI). This phenotype may become a potential target of future clinical therapeutic trials. The average disease duration of V180I gCJD patients is 23–27 months; however, considerably long-term survivors are also reported. The factors influencing survival and the clinicopathological characteristics of long-term survivors remain unknown. Herein, we report clinicopathological findings of a long-term survivor of V180I gCJD. A 78-year old woman was admitted to our hospital due to dementia and left hand tremor approximately 1.5 months after symptom onset. Neurological examination revealed dementia, frontal signs, and left hand tremor at admission. She had no family history of dementia or other neurological disease. DW-MRI revealed cortical oedematous hyper-intensities in the bilateral frontal lobes and the right temporal and parietal lobes. PRNP gene analysis indicated a V180I mutation with methionine homozygosity at codon 129. The symptoms gradually progressed, and she died of aspiration pneumonia 61 months after symptom onset. Neuropathological examination revealed severe cerebral atrophy with moderate to severe gliosis, but the brainstem was well preserved. Various-sized and non-confluent vacuole type spongiform changes were extensively observed in the cerebral cortices. Prion protein (PrP) immunostaining revealed weak and synaptic-type PrP deposits in the cerebral cortices. We consider that long-term tube feeding, and very mild brainstem involvement may be associated with the long-term survival of our V180I gCJD patient.