A case report of genetic prion disease with two different PRNP variants
Megan Piazza Thomas W. Prior Prabhjot S. Khalsa Brian Appleby
First published: 17 January 2020 https://doi.org/10.1002/mgg3.1134
Funding information:
The National Prion Disease Pathology Surveillance Center is funded by CDC (NU38CK00048).
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Abstract
Background
Prion diseases are a group of lethal neurodegenerative conditions that occur when the normal, cellular form of the prion protein (PrPC) is converted into an abnormal, scrapie, form of the protein (PrPSc). Disease may be caused by genetic, infectious, or sporadic etiologies. The genetic form of prion disease comprises~10%–15% of all cases. Prion disease is typically inherited in an autosomal dominant manner. The low incidence of disease makes it highly unlikely that a patient would have two different pathogenic variants. However, we recently identified a case in which the patient did have two pathogenic PRNP variants and presented with an atypical phenotype.
Methods
The patient was evaluated at the Washington Hospital Healthcare System in Fremont, CA. The clinical information for this case report was obtained retrospectively. Variants in the PRNP were identified by polymerase chain reaction (PCR) amplification of exon two of the gene followed by bi‐directional sequence analysis. To determine the phase of the identified variants, a restriction enzyme digestion was utilized, followed by sequence analysis of the products. Cerebral spinal fluid (CSF) was analyzed for surrogate markers of prion disease, 14–3–3 and Tau proteins. CSF real‐time quaking‐induced conversion (RT‐QuIC) assays were also performed.
Results
The patient was a compound heterozygote for the well‐characterized c.628G>A (p.Val210Ile) variant and the rare octapeptide deletion of two repeats [c.202_249del48 (p.P68_Q83del)]. Clinically, the patient presented with an early onset demyelinating peripheral neuropathy, followed by later onset cognitive symptoms.
Conclusion
This presentation is reminiscent of prion protein knockout mice whose predominate symptom, due to complete loss of PrP, was late‐onset peripheral neuropathy. To our knowledge this is the first case reported of a patient with prion disease who had two different pathogenic variants in PRNP.
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In conclusion, we have identified a unique case of genetic CJD that had two different PRNP variants. The patient was compound heterozygous for the well‐characterized c.628G>A (p.V210I) variant and the more rare octapeptide deletion of two repeats [c.202_249del48 (p.P68_Q83del)]. He was also homozygous for methionine at the polymorphic codon 129 c.385A (p.129M). The initial symptoms included an early onset peripheral neuropathy, followed by later‐onset cognitive symptoms. The presence of two different variants in the PRNP may have created an altered PrP which contributed to the unique clinical phenotype of the patient.
10. ZOONOTIC, ZOONOSIS, CHRONIC WASTING DISEASE CWD TRANSMISSIBLE SPONGIFORM ENCEPHALOPATHY TSE PRION AKA MAD DEER ELK DISEASE IN HUMANS, has it already happened, that should be the question...
''In particular the US data do not clearly exclude the possibility of human (sporadic or familial) TSE development due to consumption of venison. The Working Group thus recognizes a potential risk to consumers if a TSE would be present in European cervids.'' Scientific opinion on chronic wasting disease (II)
EFSA Panel on Biological Hazards (BIOHAZ) Antonia Ricci Ana Allende Declan Bolton Marianne Chemaly Robert Davies Pablo Salvador Fernández Escámez ... See all authors
First published: 17 January 2018 https://doi.org/10.2903/j.efsa.2018.5132 ;
also, see;
8. Even though human TSE‐exposure risk through consumption of game from European cervids can be assumed to be minor, if at all existing, no final conclusion can be drawn due to the overall lack of scientific data.
***> In particular the US data do not clearly exclude the possibility of human (sporadic or familial) TSE development due to consumption of venison.
The Working Group thus recognizes a potential risk to consumers if a TSE would be present in European cervids. It might be prudent considering appropriate measures to reduce such a risk, e.g. excluding tissues such as CNS and lymphoid tissues from the human food chain, which would greatly reduce any potential risk for consumers.. However, it is stressed that currently, no data regarding a risk of TSE infections from cervid products are available.
snip...
The tissue distribution of infectivity in CWD‐infected cervids is now known to extend beyond CNS and lymphoid tissues. While the removal of these specific tissues from the food chain would reduce human dietary exposure to infectivity, exclusion from the food chain of the whole carcass of any infected animal would be required to eliminate human dietary exposure.
85%+ of all human TSE prion, i.e. sporadic CJD, does NOT happen spontaneously, as some would wish you to think. never say never with the TSE Prion disease. ...terry
***Moreover, sporadic disease has never been observed in breeding colonies or primate research laboratories, most notably among hundreds of animals over several decades of study at the National Institutes of Health25, and in nearly twenty older animals continuously housed in our own facility.***
Volume 2: Science
4. The link between BSE and vCJD
Summary 4.29 The evidence discussed above that vCJD is caused by BSE seems overwhelming. Uncertainties exist about the cause of CJD in farmers, their wives and in several abattoir workers. It seems that farmers at least might be at higher risk than others in the general population. 1 Increased ascertainment (ie, increased identification of cases as a result of greater awareness of the condition) seems unlikely, as other groups exposed to risk, such as butchers and veterinarians, do not appear to have been affected. The CJD in farmers seems to be similar to other sporadic CJD in age of onset, in respect to glycosylation patterns, and in strain-typing in experimental mice. Some farmers are heterozygous for the methionine/valine variant at codon 129, and their lymphoreticular system (LRS) does not contain the high levels of PrPSc found in vCJD.
***>It remains a remote possibility that when older people contract CJD from BSE the resulting phenotype is like sporadic CJD and is distinct from the vCJD phenotype in younger people...end
BSE INQUIRY
SATURDAY, JUNE 23, 2018
CDC
***> Diagnosis of Methionine/Valine Variant Creutzfeldt-Jakob Disease by Protein Misfolding Cyclic Amplification
Volume 24, Number 7—July 2018 Dispatch
Saturday, February 2, 2019
CWD GSS TSE PRION SPINAL CORD, Confucius Ponders, What if?
snip...
***> In particular the US data do not clearly exclude the possibility of human (sporadic or familial) TSE development due to consumption of venison. The Working Group thus recognizes a potential risk to consumers if a TSE would be present in European cervids.'' Scientific opinion on chronic wasting disease (II) <***
REVIEW
***> In conclusion, sensory symptoms and loss of reflexes in Gerstmann-Sträussler-Scheinker syndrome can be explained by neuropathological changes in the spinal cord. We conclude that the sensory symptoms and loss of lower limb reflexes in Gerstmann-Sträussler-Scheinker syndrome is due to pathology in the caudal spinal cord. <***
***> The clinical and pathological presentation in macaques was mostly atypical, with a strong emphasis on spinal cord pathology.<***
***> The notion that CWD can be transmitted orally into both new-world and old-world non-human primates asks for a careful reevaluation of the zoonotic risk of CWD. <***
***> All animals have variable signs of prion neuropathology in spinal cords and brains and by supersensitive IHC, reaction was detected in spinal cord segments of all animals.<***
***> In particular the US data do not clearly exclude the possibility of human (sporadic or familial) TSE development due to consumption of venison. The Working Group thus recognizes a potential risk to consumers if a TSE would be present in European cervids.'' Scientific opinion on chronic wasting disease (II) <***
Thursday, March 8, 2018
Familial human prion diseases associated with prion protein mutations Y226X and G131V are transmissible to transgenic mice expressing human prion protein
snip...see full text;
MONDAY, JANUARY 20, 2020
sporadic CJD one in a million, FAKE NEWS PEOPLE!
this myth has been incorrect for decades, and had been stated as such by a few, but again, the media is too lazy to do it's job and print the facts.
Terry S. Singeltary Sr.
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