Analysis of the polymorphic prion protein gene codon 129 in idiopathic Parkinson's disease

A Chinese patient with the clinical features of Parkinson's disease contains a single copy of octarepeat deletion in PRNP case report

Insertion or deletion of single copy of octapeptide repeat (OR) in human PrP protein are considered as polymorphism, while of insertions of more numbers of OR and deletion of two copies of OR are associated with genetic prion diseases.Here, we reported a 58-year-old female patient who displayed clinical manifestations of Parkinson's disease (PD) but contained deletion mutation of single copy of OR in one PRNP allele. The patient complained involuntary tremor of left upper limb for 18 months and her symptoms aggravation for 6 months at the time referring to Chinese National CJD surveillance system. The tremor was pronounced at rest, exacerbated by stress and disappear during sleep. Her symptoms were partially relieved after receiving medicament for PD. Neurological examination recorded involuntary movement of left hand and gear-like muscle tension of left upper limb. Coordination movement reported positive of Romberg sign and unstable in heel-keen test. EEG recorded a mild abnormality, but without periodic sharp wave complexes (PSWC). MRI showed a mild write matter demyelination. CSF protein 14-3-3 was negative. PRNP sequencing revealed heterozygosity of single copy deletion on ORs (R1-2-3-4/R1-2-2-3-4).No family history of neurodegenerative disease was recorded. Such case with a single copy of OR deletion in PRNP displaying the feature of PD is rarely reported in Chinese mainland.

Mutational analysis of PRNP in Alzheimer's disease and frontotemporal dementia in China

The prion protein (PRNP) gene is associated with prion diseases, whereas variants of the PRNP gene may also explain some cases of Alzheimer disease (AD) and frontotemporal dementia (FTD) in Caucasian populations. To determine the prevalence of the PRNP gene in patients with AD and FTD in China, we screened all exons of the PRNP gene in a cohort of 683 cases (606 AD and 77 FTD) in the Chinese Han population and we detected a novel missense mutation p.S17G in a late-onset AD (LOAD) patient. Furthermore, we analyzed the PRNP M/V polymorphism at codon 129, which was previously reported as a risk factor. However, there were no significant differences in genotype and allele frequency either in AD (OR = 0.75[0.378-1.49], P = 0.492), or FTD patients (OR = 2.046[0.265-15.783], P = 0.707). To our knowledge, this is the first study to reveal a correlation between the PRNP gene and Chinese AD and FTD patients in a large cohort. This study reports a novel p.S17G mutation in a clinically diagnosed LOAD patient, suggesting that the PRNP mutation is present in Chinese AD patients, whereas, M129V polymorphism is not a risk factor for AD or FTD in the Chinese Han population.

Codon 129 polymorphism of prion protein gene in is not a risk factor for Alzheimer's disease

Interaction of prion protein and amyloid-b oligomers has been demonstrated recently. Homozygosity at prion protein gene (PRNP) codon 129 is associated with higher risk for Creutzfeldt-Jakob disease. This polymorphism has been addressed as a possible risk factor in Alzheimer disease (AD).ObjectiveTo describe the association between codon 129 polymorphisms and AD.MethodsWe investigated the association of codon 129 polymorphism of PRNP in 99 AD patients and 111 controls, and the association between this polymorphism and cognitive performance. Other polymorphisms of PRNP and additive effect of apolipoprotein E gene (ApoE) were evaluated.ResultsCodon 129 genotype distribution in AD 45.5% methionine (MM), 42.2% methionine valine (MV), 12.1% valine (VV); and 39.6% MM, 50.5% MV, 9.9% VV among controls (p>0.05). There were no differences of cognitive performance concerning codon 129. Stratification according to ApoE genotype did not reveal difference between groups.ConclusionCodon 129 polymorphism is not a risk factor for AD in Brazilian patients.

The prion protein M129V polymorphism: longevity and cognitive impairment among Polish centenarians

The PRNP gene encodes the cellular isoform of prion protein (PrP (c) ). The M129V polymorphism influences the risk of prion diseases and may modulate the rate of neurodegeneration with age. We present the first study of the polymorphism among Polish centenarians. In the control group (n = 165, ages 18 to 56 years) the observed M129V genotype frequencies agreed with those expected according to the Hardy-Weinberg equilibrium (MM, MV, VV): 43%, 44%, 13% (HWE p > 0.05). Among centenarians (n = 150, ages 100 to 107) both homozygotes were more common than expected and HWE was rejected: 46%, 37%, 17% (expected 42%, 46%, 13%; HWE p = 0.025). This finding is consistent with a higher mortality rate among heterozygotes. However, the observed allele and genotype frequencies did not differ significantly between the oldest-old and the young controls. The genotypic frequencies were not related to severe cognitive impairment among the centenarians.

Parkinson disease: associated disorders in the Norwegian population based incident ParkWest study

Parkinson's disease (PD) may be associated with a number of different diseases due to common risk factors or overlapping symptomatology. We have asked for possible associated disorders in a Norwegian population of incident PD patients and controls, the Norwegian ParkWest study. The patients were diagnosed according to the Gelb criteria. 212 incident PD patients and 175 age and gender matched controls were included. PD patients and controls were asked for information on earlier medical history and family history. PD patients had a higher frequency of self-reported symptoms of depression (p = 0.003) and anxiety disorders (p = 0.004) before baseline. They tended to have a higher frequency of diabetes (p = 0.09) and had a higher frequency of prior stroke or TIA (p = 0.004).

Euglycemic agent-mediated hypothalamic transcriptomic manipulation in the N171-82Q model of Huntington disease is related to their physiological efficacy

Our aim was to employ novel analytical methods to investigate the therapeutic treatment of the energy regulation dysfunction occurring in a Huntington disease (HD) mouse model. HD is a neurodegenerative disorder that is characterized by progressive motor impairment and cognitive alterations. Changes in neuroendocrine function, body weight, energy metabolism, euglycemia, appetite function, and gut function can also occur. It is likely that the locus of these alterations is the hypothalamus. We determined the effects of three different euglycemic agents on HD progression using standard physiological and transcriptomic signature analyses. N171-82Q HD mice were treated with insulin, Exendin-4, and the newly developed GLP-1-Tf to determine whether these agents could improve energy regulation and delay disease progression. Blood glucose, insulin, metabolic hormone levels, and pancreatic morphology were assessed. Hypothalamic gene transcription, motor coordination, and life span were also determined. The N171-82Q mice exhibited significant alterations in hypothalamic gene transcription signatures and energy metabolism that were ameliorated, to varying degrees, by the different euglycemic agents. Exendin-4 or GLP-1-Tf (but not insulin) treatment also improved pancreatic morphology, motor coordination, and increased life span. Using hypothalamic transcription signature analyses, we found that the physiological efficacy variation of the drugs was evident in the degree of reversal of the hypothalamic HD pathological signature. Euglycemic agents targeting hypothalamic and energy regulation dysfunction in HD could potentially alter disease progression and improve quality of life in HD.

Genetic Creutzfeldt-Jakob disease associated with the E200K mutation: characterization of a complex proteinopathy

The E200K mutation is the most frequent prion protein gene (PRNP) mutation detected worldwide that is associated with Creutzfeldt-Jakob disease (CJD) and thought to have overlapping features with sporadic CJD, yet detailed neuropathological studies have not been reported. In addition to the prion protein, deposition of tau, α-synuclein, and amyloid-β has been reported in human prion disease. To describe the salient and concomitant neuropathological alterations, we performed a systematic clinical, neuropathological, and biochemical study of 39 individuals carrying the E200K PRNP mutation originating from different European countries. The most frequent clinical symptoms were dementia and ataxia followed by myoclonus and various combinations of further symptoms, including vertical gaze palsy and polyneuropathy. Neuropathological examination revealed relatively uniform anatomical pattern of tissue lesioning, predominating in the basal ganglia and thalamus, and also substantia nigra, while the deposition of disease-associated PrP was more influenced by the codon 129 constellation, including different or mixed types of PrP(res) detected by immunoblotting. Unique and prominent intraneuronal PrP deposition involving brainstem nuclei was also noted. Systematic examination of protein depositions revealed parenchymal amyloid-β in 53.8%, amyloid angiopathy (Aβ) in 23.1%, phospho-tau immunoreactive neuritic profiles in 92.3%, neurofibrillary degeneration in 38.4%, new types of tau pathology in 33.3%, and Lewy-type α-synuclein pathology in 15.4%. TDP-43 and FUS immunoreactive protein deposits were not observed. This is the first demonstration of intensified and combined neurodegeneration in a genetic prion disease due to a single point mutation, which might become an important model to decipher the molecular interplay between neurodegeneration-associated proteins.

Octarepeat changes of prion protein in Parkinson's disease

Polymorphism in prion protein (PrP) is related to different phenotypes of spongiform encephalopathies and some mental illnesses. The octarepeat region of PrP, encompassing the codon 51 through 91, is related to cellular anti-oxidation function and may play a role in genetic contribution of PrP polymorphism to neurodegeneration, such as Parkinson's disease (PD). We analyzed the genomic patterns of PrP gene from 528 subjects and found a predominance of Met/Met variant at codon 129 of PD subjects without significant difference (97.3%, and 96.5% in controls). But among PD subjects there were one with heterozygosity of silent nucleotide substitution (NS) on octarepeats (R1-2-3g-3-4/R1-2-2-3-4) and three with heterozygosity of single copy deletion (CD) on octarepeats (R1-2-3-4/R1-2-2-3-4). Consistent genomic DNA and cDNA sequences were found in a PD subject without any octarepeat changes and the one with NS, but R1-2-3g-3-4/R1-2-2-3-4 of cDNA pattern occurred in the one with genomic CD. This is the first report of the polymorphic PrP octarepeat change among those with parkinsonism. We proposed a hypothesis about an initial secondary hairpin structure of the template strand followed by the transcript "shift backward" due to the high homology of the sequences between R2 and R3 motifs while synthesizing RNA. This phenomenon may be a key step of neurodegeneration resulting from PrP polymorphism and require further studies.

PRNP M129V homozygosity in multiple system atrophy vs. Parkinson's disease

Multiple system atrophy (MSA) is a neurodegenerative disorder of unknown etiology characterized by extrapyramidal, pyramidal, cerebellar, and autonomic dysfunction in any combination. We report a patient with a 4-year history of MSA who developed dementia associated with sporadic Creutzfeldt-Jakob disease (CJD). Our proband was MM homozygous for the M129V polymorphism within the prion protein gene (PRNP), a known risk factor for CJD. We conducted a case-control study to test the hypothesis that homozygosity for the M129V polymorphism of PRNP occurs more frequently in MSA in comparison to Parkinson's disease and healthy volunteers. A total of 63 patients with MSA, 54 age-, race- and gendermatched controls with Parkinson's disease, and 126 matched healthy volunteers were studied. The genotype analysis revealed no significant difference in the codon 129 genotype distribution in MSA as compared to controls. Nonetheless, the frequencies of the MM and VV genotypes were higher in MSA than in Parkinson's disease. Thus, homozygosity, particularly VV homozygosity, at codon 129 of PRNP is associated with MSA compared to a clinically related but pathophysiologically distinct alpha-synucleinopathy. Considering the possibility that the prion protein contributes to the pathogenesis of MSA would require confirmation of these findings in an independent patient population.

Polymorphism distribution of prion protein codon 117, 129 and 171 in Taiwan

Prion diseases compass transmissible spongiform neurodegenerative diseases from various causes, including the genetic and infectious ones. We investigated the prevalence of codon 117, 129 and 171 polymorphism in prion protein (PrP) in Taiwanese, mainly for the sake of the informative absence of this genetic distribution. Our subjects were 419 aged ones of Han ethic origin. We evaluated the PrP gene (PRNP) polymorphism by restriction fragment length polymorphism, after amplification of their genomic DNAs by polymerase chain reactions with specific primers, digested by restriction enzyme PvuII (for codon 117), NspI (for codon 129), and BbvI (for codon 171), respectively, and confirmed by nucleotide sequencing. All of the subjects were homozygotes at codon 117 (Ala/Ala, gca/gca) and 171 (Asn/Asn, aac/aac). There were no valine homozygotes (Val/Val) in our 419 subjects, and nine subjects (2.1%) showed methionine-valine heterozygosity (Mal/Val, atg/gtg). The methionine homozygotes (Met/Met) comprised the major population (97.9%), and the prevalence of distribution is different to that seen in Caucasians. The almost 100% conservation of the domain from codon 117 to 171 implies the warranty of PrP in cellular functions. The high prevalence of Met/Met alleles in Taiwan did not imply an increased risk of CJD, and the genetic susceptibility of CJD by codon 129 of PrP may be still elusive for the infectivity.

Prion protein gene M129 allele is a risk factor for Alzheimer's disease

Prion protein gene polymorphism M129V represents a known risk factor for Creutzfeldt-Jakob disease. Recently, the meta-analysis revealed that homozygosity at codon 129 is connected with increased risk of Alzheimer's disease (AD). To determine whether M129V polymorphism is a risk factor for AD we analyzed a group of early-onset, and late-onset Polish AD patients. We observed that in LOAD patients there is a statistically significant increase of MM (p=0.0028) and decrease of MV (p=0.0006) genotype frequency, as compared to controls. When both groups were stratified according to APOE4 status, increase of MM and decrease of MV genotype frequency were significant in the LOAD subgroup with no APOE4 (p=0.017, and p=0.018, respectively). In the subgroup with APOE4 allele, only MV genotype frequency was significantly lower, as compared to controls (p=0.035). However, no interaction was found between APOE4 status and M129V polymorphism. We conclude that MM genotype increases LOAD risk in Polish population independently from the APOE4 status.