Rare genetic Creutzfeldt-Jakob disease with E196A mutation: a case report

Creutzfeldt-Jakob disease presenting as Korsakoff syndrome caused by E196A mutation in PRNP gene: A case report

BACKGROUND

Prion diseases are a group of degenerative nerve diseases that are caused by infectious prion proteins or gene mutations. In humans, prion diseases result from mutations in the prion protein gene (PRNP). Only a limited number of cases involving a specific PRNP mutation at codon 196 (E196A) have been reported. The coexistence of Korsakoff syndrome in patients with Creutzfeldt-Jakob disease (CJD) caused by E196A mutation has not been documented in the existing literature.

CASE SUMMARY

A 61-year-old Chinese man initially presented with Korsakoff syndrome, followed by rapid-onset dementia, visual hallucinations, akinetic mutism, myoclonus, and hyperthermia. The patient had no significant personal or familial medical history. Magnetic resonance imaging of the brain revealed extensive hyperintense signals in the cortex, while positron emission tomography/computed tomography showed a diffuse reduction in cerebral cortex metabolism. Routine biochemical and microorganism testing of the cerebrospinal fluid (CSF) yielded normal results. Tests for thyroid function, human immunodeficiency virus, syphilis, vitamin B1 and B12 levels, and autoimmune rheumatic disorders were normal. Blood and CSF tests for autoimmune encephalitis and autoantibody-associated paraneoplastic syndrome yielded negative results. A test for 14-3-3 protein in the CSF yielded negative results. Whole-genome sequencing revealed a disease-causing mutation in PRNP. The patient succumbed to the illness 11 months after the initial symptom onset.

CONCLUSION

Korsakoff syndrome, typically associated with alcohol intoxication, also manifests in CJD patients. Individuals with CJD along with PRNP E196A mutation may present with Korsakoff syndrome.

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.

Rare genetic E196A mutation in a patient with Creutzfeldt-Jakob disease: a case report and literature

Genetic Creutzfeldt–Jakob disease (gCJD) is characterized by mutations in the PRNP gene and represents approximately 10–15% of the human prion diseases. Here, we report a 42-year-old Chinese man who was diagnosed with gCJD. The patient had a rare mutation in codon 196 (E196A) of PRNP leading to an exchange of amino acid from glutamic acid (E) to alanine (A). The polymorphism of codon 129 in the patient was methionine homozygote. His mother and daughter are asymptomatic carriers of the same mutation. The clinical manifestations were similar to those of sporadic CJD. 14-3-3 protein was positive in cerebrospinal fluid, and there were sharp slow complex waves in electroencephalography and ribbon-like signals on magnetic resonance imaging (MRI). The main complaints of patient changed from visual space and visual colour to psychotic symptoms with enhanced high signal intensity on the occipital and frontal cortices on MRI. We compared the clinical characteristics of the current patient with those of previously reported Chinese patients with other gCJD of E196A mutation to summarize the common features of E196A gCJD.