Creutzfeldt-Jakob disease surveillance in Australia: update to December 2014.

Nation-wide surveillance of human transmissible spongiform encephalopathies (also known as prion diseases), the most common being Creutzfeldt-Jakob disease, is performed by the Australian National Creutzfeldt-Jakob Disease Registry, based at the University of Melbourne. Prospective surveillance has been undertaken since 1993 and over this dynamic period in transmissible spongiform encephalopathy research and understanding, the unit has evolved and adapted to changes in surveillance practices and requirements concomitant with the emergence of new disease subtypes, improvements in diagnostic capabilities and the overall heightened awareness of prion diseases in the health care setting. In 2014, routine national surveillance continued and this brief report provides an update of the cumulative surveillance data collected by the Australian National Creutzfeldt-Jakob Disease Registry prospectively from 1993 to December 2014, and retrospectively to 1970.

LGI1 antibody encephalopathy overlapping with sporadic Creutzfeldt-Jakob disease.

OBJECTIVE: To report a rare case of leucine-rich, glioma inactivated 1 (LGI1) antibody-mediated autoimmune encephalopathy clinically overlapping with pathologically confirmed sporadic Creutzfeldt-Jakob disease (CJD). METHODS: The patient was investigated with repeated brain MRI, EEG, CSF examination, whole-body fluorodeoxy-glucose positron emission tomography, genetic analysis of the prion protein gene (PRNP), and extensive serologic screening for paraneoplastic and autoimmune encephalopathy markers. Written informed consent was obtained from the patient's next of kin for access to clinical files for research purposes and for publication. RESULTS: The patient was a 77-year-old man who presented with faciobrachial dystonic seizures (FBDS) secondary to LGI1 antibody-mediated autoimmune encephalopathy, with suggestive MRI findings and a complete response to treatment with combinatorial immunosuppression. Stereotactic biopsy of a nonenhancing T1 hyperintense basal ganglia lesion during the initial FBDS phase, albeit following immunosuppression, did not disclose evidence of lymphocytic inflammation. Following full remission of the FBDS, the patient manifested a rapidly progressive dementia associated with gross motor decline confirmed to be CJD at autopsy (molecular subtype VV3), with no evidence of a pathogenic PRNP mutation. CONCLUSIONS: Our patient highlights that these rare diseases are not invariably mutually exclusive and underscores the benefits of comprehensive neuropathologic examination of the brain to achieve an accurate diagnosis, especially in complex cases when the clinical trajectory dramatically deviates and a concomitant disease may need to be conscientiously considered to best explain the new clinical course.

Quantifying prion disease penetrance using large population control cohorts.

More than 100,000 genetic variants are reported to cause Mendelian disease in humans, but the penetrance-the probability that a carrier of the purported disease-causing genotype will indeed develop the disease-is generally unknown. We assess the impact of variants in the prion protein gene (PRNP) on the risk of prion disease by analyzing 16,025 prion disease cases, 60,706 population control exomes, and 531,575 individuals genotyped by 23andMe Inc. We show that missense variants in PRNP previously reported to be pathogenic are at least 30 times more common in the population than expected on the basis of genetic prion disease prevalence. Although some of this excess can be attributed to benign variants falsely assigned as pathogenic, other variants have genuine effects on disease susceptibility but confer lifetime risks ranging from <0.1 to ~100%. We also show that truncating variants in PRNP have position-dependent effects, with true loss-of-function alleles found in healthy older individuals, a finding that supports the safety of therapeutic suppression of prion protein expression.

Creutzfeldt-Jakob disease surveillance in Australia: update to December 2015.

Nation-wide surveillance of human transmissible spongiform encephalopathies (also known as prion diseases), the most common being Creutzfeldt-Jakob disease, is performed by the Australian National Creutzfeldt-Jakob Disease Registry, based at the University of Melbourne. Prospective surveillance has been undertaken since 1993 and over this dynamic period in transmissible spongiform encephalopathy research and understanding, the unit has evolved and adapted to changes in surveillance practices and requirements concomitant with the delineation of new disease subtypes, improvements in diagnostic capabilities and the overall heightened awareness of prion diseases in the health care setting. In 2015, routine national surveillance continued and this brief report provides an update of the cumulative surveillance data collected by the Australian National Creutzfeldt-Jakob Disease Registry prospectively from 1993 to December 2015, and retrospectively to 1970.

Broadcasting of cortical activity to the olfactory bulb.

Odor representations are initially formed in the olfactory bulb, which contains a topographic glomerular map of odor molecular features. The bulb transmits sensory information directly to piriform cortex, where it is encoded by distributed ensembles of pyramidal cells without spatial order. Intriguingly, piriform cortex pyramidal cells project back to the bulb, but the information contained in this feedback projection is unknown. Here, we use imaging in awake mice to directly monitor activity in the presynaptic boutons of cortical feedback fibers. We show that the cortex provides the bulb with a rich array of information for any individual odor and that cortical feedback is dependent on brain state. In contrast to the stereotyped, spatial arrangement of olfactory bulb glomeruli, cortical inputs tuned to different odors commingle and indiscriminately target individual glomerular channels. Thus, the cortex modulates early odor representations by broadcasting sensory information diffusely onto spatially ordered bulbar circuits.

Ascertainment bias causes false signal of anticipation in genetic prion disease.

Anticipation is the phenomenon whereby age of onset in genetic disease decreases in successive generations. Three independent reports have claimed anticipation in Creutzfeldt-Jakob disease (CJD) caused by the c.598G > A mutation in PRNP encoding a p.Glu200Lys (E200K) substitution in the prion protein. If confirmed, this finding would carry clear implications for genetic counseling. We analyzed pedigrees with this mutation from four prion centers worldwide (n = 217 individuals with the mutation) to analyze age of onset and death in affected and censored individuals. We show through simulation that selective ascertainment of individuals whose onset falls within the historical window since the mutation's 1989 discovery is sufficient to create robust false signals both of anticipation and of heritability of age of onset. In our data set, the number of years of anticipation observed depends upon how strictly the data are limited by the ascertainment window. Among individuals whose disease was directly observed at a study center, a 28-year difference between parent and child age of onset is observed (p = 0.002), but including individuals ascertained retrospectively through family history reduces this figure to 7 years (p = 0.005). Applying survival analysis to the most thoroughly ascertained subset of data eliminates the signal of anticipation. Moreover, even non-CJD deaths exhibit 16 years anticipation (p = 0.002), indicating that ascertainment bias can entirely explain observed anticipation. We suggest that reports of anticipation in genetic prion disease are driven entirely by ascertainment bias. Guidelines for future studies claiming statistical evidence for anticipation are suggested.

Targeted metabolomics of Physaria fendleri, an industrial crop producing hydroxy fatty acids.

Physaria fendleri (syn. Lesquerella) is a Brassicaceae producing lesquerolic acid, a highly valued hydroxy fatty acid that could be used for several industrial applications, such as cosmetics, lubricating greases, paints, plastics and biofuels. Free of toxins, Physaria oil is an attractive alternative to imported castor (Ricinus communis) oil, and is hence on the verge of commercialization. Gas chromatography-mass spectrometry analysis of fatty acid methyl esters revealed that lesquerolic acid was synthesized and accumulated in the embryos, reaching 60% (w/w) of the total fatty acids. The sequential extraction and characterization of biomass compounds revealed that Physaria embryo metabolism switched from protein to fatty acid biosynthesis between 18 and 24 days post-anthesis (DPA). In order to unravel the metabolic pathways involved in fatty acid synthesis, a targeted metabolomics study was conducted on Physaria embryos at different stages of development. For this purpose, two novel high-throughput liquid chromatography-tandem mass spectrometry methods were developed and validated to quantify sugars, sugar alcohols and amino acids. Specificity was achieved using multiple reaction monitoring, and the limits of quantification were in the pmole-fmole range. The comparative metabolomic study underlined that: (i) the majority of the metabolites accumulate in Physaria embryos between 18 and 27 DPA; (ii) the oxidative pentose phosphate pathway, glycolysis, the tricarboxilic acid cycle and the anaplerotic pathway drain a substantial amount of carbon; and (iii) ribulose-1,5-bisphosphate is present, which specifically indicates that the Calvin cycle is occurring. The importance and the relevance of these findings regarding fatty acid synthesis were discussed.

Creutzfeldt-Jakob disease surveillance in Australia, update to December 2013.

Nation-wide surveillance of transmissible spongiform encephalopathies including Creutzfeldt-Jakob disease, is performed by the Australian National Creutzfeldt-Jakob Disease Registry, based at the University of Melbourne. Surveillance has been undertaken since 1993. Over this dynamic period in transmissible spongiform encephalopathy research and understanding, the unit has evolved and adapted to changes in surveillance practices and requirements, the emergence of new disease subtypes, improvements in diagnostic capabilities and the overall heightened awareness and understanding of Creutzfeldt-Jakob disease and other transmissible spongiform encephalopathies in the health care setting. In 2013, routine surveillance continued and this brief report provides an update of the surveillance data collected by the Australian National Creutzfeldt-Jakob Disease Registry prospectively from 1993 to December 2013, and retrospectively to 1970. The report highlights the recent multi-national collaborative study published that has verified the correlation between surveillance intensity and reported disease incidence.

A genome wide association study links glutamate receptor pathway to sporadic Creutzfeldt-Jakob disease risk.

We performed a genome-wide association (GWA) study in 434 sporadic Creutzfeldt-Jakob disease (sCJD) patients and 1939 controls from the United Kingdom, Germany and The Netherlands. The findings were replicated in an independent sample of 1109 sCJD and 2264 controls provided by a multinational consortium. From the initial GWA analysis we selected 23 SNPs for further genotyping in 1109 sCJD cases from seven different countries. Five SNPs were significantly associated with sCJD after correction for multiple testing. Subsequently these five SNPs were genotyped in 2264 controls. The pooled analysis, including 1543 sCJD cases and 4203 controls, yielded two genome wide significant results: rs6107516 (p-value=7.62x10-9) a variant tagging the prion protein gene (PRNP); and rs6951643 (p-value=1.66x10-8) tagging the Glutamate Receptor Metabotropic 8 gene (GRM8). Next we analysed the data stratifying by country of origin combining samples from the pooled analysis with genotypes from the 1000 Genomes Project and imputed genotypes from the Rotterdam Study (Total n=12967). The meta-analysis of the results showed that rs6107516 (p-value=3.00x10-8) and rs6951643 (p-value=3.91x10-5) remained as the two most significantly associated SNPs. Rs6951643 is located in an intronic region of GRM8, a gene that was additionally tagged by a cluster of 12 SNPs within our top100 ranked results. GRM8 encodes for mGluR8, a protein which belongs to the metabotropic glutamate receptor family, recently shown to be involved in the transduction of cellular signals triggered by the prion protein. Pathway enrichment analyses performed with both Ingenuity Pathway Analysis and ALIGATOR postulates glutamate receptor signalling as one of the main pathways associated with sCJD. In summary, we have detected GRM8 as a novel, non-PRNP, genome-wide significant marker associated with heightened disease risk, providing additional evidence supporting a role of glutamate receptors in sCJD pathogenesis.

Surveillance for Creutzfeldt-Jakob disease in Australia: update to December 2012.

Nation-wide surveillance for transmissible spongiform encephalopathies including Creutzfeldt-Jakob disease (CJD) is undertaken by the Australian National Creutzfeldt-Jakob disease Registry (ANCJDR), based at the University of Melbourne. Surveillance has been undertaken since 1993. During this period the unit has evolved and adapted to changes in surveillance practices and requirements, the emergence of new disease subtypes, improvements in diagnostic capabilities and the overall heightened awareness and understanding of CJD and other transmissible spongiform encephalopathies in the health care setting. In 2012, routine surveillance continued. This brief report provides an update on the surveillance data collected by the ANCJDR prospectively from 1993 to December 2012, and retrospectively to 1970. It also highlights the recent release of the revised Australian CJD Infection Control Guidelines.

Intensity of human prion disease surveillance predicts observed disease incidence.

BACKGROUND: Prospective national screening and surveillance programmes serve a range of public health functions. Objectively determining their adequacy and impact on disease may be problematic for rare disorders. We undertook to assess whether objective measures of disease surveillance intensity could be developed for the rare disorder sporadic Creutzfeldt-Jakob disease (CJD) and whether such measures correlate with disease incidence. METHOD: From 10 countries with national human prion disease surveillance centres, the annual number of suspected prion disease cases notified to each national unit (n=17,610), referrals for cerebrospinal fluid (CSF) 14-3-3 protein diagnostic testing (n=28,780) and the number of suspect cases undergoing diagnostic neuropathological examination (n=4885) from 1993 to 2006 were collected. Age and survey year adjusted incidence rate ratios with 95% CIs were estimated using Poisson regression models to assess risk factors for sporadic, non-sporadic and all prion disease cases. RESULTS: Age and survey year adjusted analysis showed all three surveillance intensity measures (suspected human prion disease notifications, 14-3-3 protein diagnostic test referrals and neuropathological examinations of suspect cases) significantly predicted the incidence of sporadic CJD, non-sporadic CJD and all prion disease. CONCLUSIONS: Routine national surveillance methods adjusted as population rates allow objective determination of surveillance intensity, which correlates positively with reported incidence for human prion disease, especially sporadic CJD, largely independent of national context. The predictive relationship between surveillance intensity and disease incidence should facilitate more rapid delineation of aberrations in disease occurrence and assessment of the adequacy of disease monitoring by national registries.

Unusual clinical and molecular-pathological profile of gerstmann-Sträussler-Scheinker disease associated with a novel PRNP mutation (V176G).

IMPORTANCE: Here we describe the unusual clinical and molecular-neuropathological profile of a case of Gerstmann-Sträussler-Scheinker disease associated with a novel prion protein (PRNP) gene mutation. OBSERVATIONS: This case report from the Australian National Creutzfeldt-Jakob Disease Registry concerns a 61-year-old British-born woman with no history of neurodegenerative disorder in first-degree relatives. Rapidly progressive dementia, altered behavior, and cerebellar ataxia dominated the clinical picture in the period immediately following minor elective surgery, with death 1 month later in an akinetic-mute state. Brain histopathological examination revealed neuronal loss, scant foci of spongiform change, and diffuse multicentric amyloid plaques, selectively immunoreactive for prion protein, within the cerebral and cerebellar cortices and deep gray matter. Tau immune-reactive neurofibrillary tangles and neuritic threads were present in the cerebral cortex. PRNP sequencing demonstrated a valine to glycine mutation at codon 176, with valine homozygosity at polymorphic codon 129. Western-blot analysis of frozen brain tissue displayed a nonclassic protease-resistant prion protein banding pattern, with a prominent approximately 8-kDa protease-resistant fragment. CONCLUSIONS AND RELEVANCE: Reported is a proband with a novel PRNP mutation associated with neuropathologically confirmed Gerstmann-Sträussler-Scheinker disease displaying a somewhat unusual constellation of clinicopathological features, which overall subserve to further broaden an already diverse phenotypic spectrum.

Cortical feedback control of olfactory bulb circuits.

Olfactory cortex pyramidal cells integrate sensory input from olfactory bulb mitral and tufted (M/T) cells and project axons back to the bulb. However, the impact of cortical feedback projections on olfactory bulb circuits is unclear. Here, we selectively express channelrhodopsin-2 in olfactory cortex pyramidal cells and show that cortical feedback projections excite diverse populations of bulb interneurons. Activation of cortical fibers directly excites GABAergic granule cells, which in turn inhibit M/T cells. However, we show that cortical inputs preferentially target short axon cells that drive feedforward inhibition of granule cells. In vivo, activation of olfactory cortex that only weakly affects spontaneous M/T cell firing strongly gates odor-evoked M/T cell responses: cortical activity suppresses odor-evoked excitation and enhances odor-evoked inhibition. Together, these results indicate that although cortical projections have diverse actions on olfactory bulb microcircuits, the net effect of cortical feedback on M/T cells is an amplification of odor-evoked inhibition.

Surveillance of Creutzfeldt-Jakob disease in Australia: update to December 2011.

The Australian National Creutzfeldt-Jakob disease Registry (ANCJDR) is a Commonwealth Government-funded surveillance unit, responsible for the ascertainment of all cases of human transmissible spongiform encephalopathy (also known as prion diseases) in Australia. Having been in operation for 18 years, the activities of the ANCJDR have evolved and expanded over this timeframe, with the ANCJDR providing clinical, diagnostic and infection control advice and service. This update provides a review of the activities of the ANCJDR during 2011 and analysis of both prospective and retrospective (to 1970) data collected from 1993 to 31 December 2011.

The prion protein preference of sporadic Creutzfeldt-Jakob disease subtypes.

Sporadic Creutzfeldt-Jakob disease (CJD) is the most prevalent manifestation of the transmissible spongiform encephalopathies or prion diseases affecting humans. The disease encompasses a spectrum of clinical phenotypes that have been correlated with molecular subtypes that are characterized by the molecular mass of the protease-resistant fragment of the disease-related conformation of the prion protein and a polymorphism at codon 129 of the gene encoding the prion protein. A cell-free assay of prion protein misfolding was used to investigate the ability of these sporadic CJD molecular subtypes to propagate using brain-derived sources of the cellular prion protein (PrP(C)). This study confirmed the presence of three distinct sporadic CJD molecular subtypes with PrP(C) substrate requirements that reflected their codon 129 associations in vivo. However, the ability of a sporadic CJD molecular subtype to use a specific PrP(C) substrate was not determined solely by codon 129 as the efficiency of prion propagation was also influenced by the composition of the brain tissue from which the PrP(C) substrate was sourced, thus indicating that nuances in PrP(C) or additional factors may determine sporadic CJD subtype. The results of this study will aid in the design of diagnostic assays that can detect prion disease across the diversity of sporadic CJD subtypes.

Surveillance of Creutzfeldt-Jakob disease in Australia: update to December 2010.

Since the establishment of the Australian National Creutzfeldt-Jakob disease Registry (ANCJDR) its activities have expanded from prospectively investigating additional iatrogenic Creutzfeldt-Jakob disease cases to include: retrospective ascertainment to 1970; provision of expert opinions in the area of infection control management; provide diagnostic testing services for all suspect cases; and maintenance of national and international collaborations in conjunction with routine surveillance responsibilities. An update of the ANCJDR's surveillance activities and outcomes between 1 April and 31 December 2010 is herein presented, including a summation of a recent publication by the ANCJDR. The shorter reporting period is due to a contractual change with the Department of Health and Ageing in 2010, resulting in the reporting timeframe shifting to align with full calendar years.

Increased intrahepatic apoptosis but reduced immune activation in HIV-HBV co-infected patients with advanced immunosuppression.

OBJECTIVE: to determine if intrahepatic immune activation is increased in HIV-hepatitis B virus (HBV) co-infected patients compared to HBV mono-infected patients and whether this reduced following HBV-active antiretroviral therapy (ART) in HIV-HBV co-infected patients. DESIGN: : Case-control observational study. METHODS: we examined liver biopsies for markers of T-cell and monocyte infiltration and activation, natural killer cells, hepatic stellate cell (HSC) activation (staining for alpha smooth muscle actin) and apoptosis [using terminal dUTP nick-end labelling (TUNEL)] in treatment-naive Asian HIV-HBV co-infected (n = 16) and HBV mono-infected patients matched for age and HBV e-antigen status (n = 16). Liver biopsies from a subset of co-infected patients (n = 15) were also compared prior to and following 48 weeks of HBV-active ART. RESULTS: HIV-HBV co-infected patients had a median CD4 T-cell count of 25 cells/microl and lower alanine aminotransferase levels than HBV mono-infected patients (P = 0.03). In HIV-HBV co-infected patients, hepatocyte apoptosis was increased (P = 0.04) but there were fewer intrahepatic CD4 and CD8 T cells (P < 0.001), lower activation of intrahepatic T cells, Kupffer cells and HSC (P = 0.002, 0.008 and < 0.001, respectively). Following ART, there was a significant decrease in intrahepatic HBsAg staining (P = 0.04) and Kupffer cell activation (P = 0.003). CONCLUSIONS: we found no evidence of increased intrahepatic mononuclear and HSC activation in this cohort of HIV-HBV co-infected individuals with advanced immune suppression. An increase in intra-hepatic apoptosis in HIV-HBV co-infected individuals may potentially contribute to accelerated fibrosis in this setting.

A mammalian melanopsin in the retina of a fresh water turtle, the red-eared slider (Trachemys scripta elegans).

A mammalian-like melanopsin (Opn4m) has been found in all major vertebrate classes except reptile. Since the pupillary light reflex (PLR) of the fresh water turtle takes between 5 and 10 min to achieve maximum constriction, and since photosensitive retinal ganglion cells (ipRGCs) in mammals use Opn4m to control their slow sustained pupil responses, we hypothesized that a Opn4m homolog exists in the retina of the turtle. To identify its presence, retinal tissue was dissected from seven turtles, and total RNA extracted. Reverse transcriptase-polymerase chain reactions (RT-PCRs) were carried out to amplify gene sequences using primers targeting the highly conserved core region of Opn4m, and PCR products were analyzed by gel electrophoresis and sequenced. Sequences derived from a 1004-bp PCR product were compared to those stored in GenBank by the basic local alignment search tool (BLAST) algorithm and returned significant matches to several Opn4ms from other vertebrates including chicken. Quantitative real-time PCR (qPCR) was also carried out to compare expression levels of Opn4m in different tissues. The normalized expression level of Opn4m in the retina was higher in comparison to other tissue types: iris, liver, lung, and skeletal muscle. The results suggest that Opn4m exists in the retina of the turtle and provides a possible explanation for the presence of a slow PLR. The turtle is likely to be a useful model for further understanding the photoreceptive mechanisms in the retina which control the dynamics of the PLR.

Iatrogenic Creutzfeldt-Jakob disease in Australia: time to amend infection control measures for pituitary hormone recipients?

From 1967, the Australian Human Pituitary Hormone Program offered treatment for short stature and infertility using human cadaver-acquired pituitary hormones (human growth hormone [hGH] and human pituitary gonadotrophin [hPG]). The program was suspended in 1985 when a growth-hormone recipient in the United States developed Creutzfeldt-Jakob disease (CJD), an incurable and rapidly progressive neurodegenerative disorder. Since this time, recipients have lived with the significant anxiety that they have an elevated risk of developing CJD. Furthermore, additional CJD infection control measures are required when recipients undergo some types of surgery. As it is 20 years since the last Australian pituitary hormone recipient developed CJD, we evaluated the risk for Australian recipients of developing iatrogenic CJD, and compared Australian data with data from New Zealand and selected other countries who had pituitary hormone programs. Our evaluation indicates that pituitary hormone recipients in Australia have the lowest risk of developing iatrogenic CJD, and that Australia is the only country not to have experienced ongoing CJD-related deaths. Thus, we believe that: in the Australian hGH recipient cohort, the risk of developing CJD is sufficiently low for this cohort to no longer require additional infection control measures in the health care setting; and in the Australian hPG recipient cohort, if another 5 years elapses with no further occurrence of CJD in this group, the hPG recipient cohort could also be considered as not requiring additional infection control measures in the health care setting. These recommendations should not be misunderstood as implying that there is no ongoing risk, but that the risk is acceptably low and generally in keeping with guidelines that stratify the risk.