Clinical and Laboratory Features of Three Rare Chinese V210I gCJD Patients

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.

Case Report: Genetic Creutzfeldt–Jakob Disease With a G114V Mutation and One Octapeptide Repeat Deletion as a Mimic of Frontotemporal Dementia

Genetic Creutzfeldt–Jakob disease (gCJD) characterized by mutations in the prion protein (PrP) gene (PRNP) contributes to approximately 10–15% of the overall human prion diseases. Here, we report a rare mutation in the PRNP gene in a Han-Chinese family. A 36-year-old man initiated with anxiety and depression followed by progressive dementia, cogwheel-like rigidity combined with tremors, and he was diagnosed with frontotemporal lobar dementia in the first 2 years. The disease progression was relatively slow, and the patient developed into akinetic mutism in 4 years. To characterize the disease, following the pedigree studies, neuropsychological examination, neuroimaging studies, real-time quaking-induced conversion (RT-QuIC) examination, and so on were conducted. We eventually identified a rare mutation of G114V combined with one octapeptide repeats deletion (1-ORPD) in the PrP in the patient by DNA sequencing. In addition, the same mutation and deletion were subsequently identified in the patient's mother without any syndromes. His maternal grandmother had a late onset of the disease in her 60s. Given that 1-OPRD has never been reported in human prion disease before, our first report that both G114V mutation and 1-OPRD appear in the family would forward our understanding of the etiological mechanisms of the gCJD.