Late-onset Tay-Sachs disease

We discuss the assessment and differential diagnoses of a young adult Hungarian man with a 1-year history of a progressive and symmetric amyotrophic lateral sclerosis-like syndrome, along with irregular action tremor and stimulus-sensitive myoclonus of the arms. MR scan of the brain showed isolated cerebellar atrophy and formal neuropsychometric testing identified significant subclinical deficits in attention, processing speed and memory. We suspected a form of GM2 gangliosidosis, and white cell enzyme analysis showed markedly reduced enzymatic activity of β-hexosaminidase A. Genetic testing subsequently revealed two heterozygous pathogenic mutations in the HEXA gene (c.1499delT p.(Leu500fs) and c.805G>A p.(Gly269Ser)), confirming the very rare diagnosis of adult-onset Tay-Sachs disease

PET brain imaging in HIV-associated neurocognitive disorders (HAND) in the era of combination antiretroviral therapy

Effective combination antiretroviral therapy (cART) has lead to a significant reduction in the prevalence and incidence of central nervous system (CNS) HIV-associated brain disease, particularly CNS opportunistic infections and HIV encephalitis. Despite this, cognitive deficits in people living with HIV, also known as HIV-associated neurocognitive disorders (HAND) have become more prevalent in recent years. The pathogenesis of HAND is likely to be multifactorial, however recent evidence suggests that brain microglial activation is the most likely pathogenic mechanism. Recent developments in positron emission tomography (PET) brain neuroimaging using novel brain radioligands targeting a variety of physiological changes in the brains of HIV-positive individuals have improved our understanding of the mechanisms associated with the development of HAND. This review will highlight recent PET brain neuroimaging studies in the cART era, focusing on physiological and neurochemical changes associated with HAND in people living with HIV

Human herpesvirus infections and dementia or mild cognitive impairment: a systematic review and meta-analysis.

Interest is growing in the role of infectious agents in the pathogenesis of dementia, but current evidence is limited. We conducted a systematic review and meta-analysis to investigate the effect of any of eight human herpesviruses on development of dementia or mild cognitive impairment (MCI). We searched the Cochrane Library, Embase, Global Health, Medline, PsycINFO, Scopus, Web of Science, clinical trials registers and grey literature sources from inception to December 2017 for observational studies with cohort, case control or self-controlled designs, or randomised controlled trials of interventions against herpesviruses. Pooled effect estimates and 95% confidence intervals (CIs) were generated through random effects meta-analyses across studies with the same design, outcome, and virus type, method and site of measurement. We included 57 studies across various geographic settings. Past infection with herpesviruses, measured by IgG seropositivity, was generally not associated with dementia risk. A single cohort study rated moderate quality showed an association between varicella zoster virus reactivation (ophthalmic zoster) and incident dementia (HR 2.97; 95%CI, 1.89 to 4.66). Recent infection with, or reactivation of, herpes simplex virus type 1 or type 1/2 unspecified, cytomegalovirus and human herpes virus-6 measured by serum IgM, high titre IgG or clinical disease may be associated with dementia or MCI, though results were inconsistent across studies and overall evidence rated very low quality. Longitudinal population studies with robust repeated virus measurements taken sufficiently proximal to dementia onset are needed to establish whether, when and among whom herpesviruses affect dementia risk

A double-blind placebo-controlled cross-over clinical trial of DONepezil In Posterior cortical atrophy due to underlying Alzheimer's Disease: DONIPAD study.

BACKGROUND: The study investigated whether donepezil exerts symptomatic benefit in patients with posterior cortical atrophy (PCA), an atypical variant of Alzheimer's disease. METHODS: A single-centre, double-blind, placebo-controlled, cross-over clinical trial was performed to assess the efficacy of donepezil in patients with PCA. Each patient received either donepezil (5 mg once daily in the first 6 weeks and 10 mg once daily in the second 6 weeks) or placebo for 12 weeks. After a 2-week washout period, each patient received the other treatment arm during the following 12 weeks followed by another 2-week washout period. The primary outcome was the Mini-Mental State Examination (MMSE) at 12 weeks. Secondary outcome measures were five neuropsychological tests reflecting parieto-occipital function. Intention-to-treat analysis was used. For each outcome measure, carry-over effects were first assessed. If present, then analysis was restricted to the first 12-week period. Otherwise, the standard approach to the analysis of a 2 × 2 cross-over trial was used. RESULTS: Eighteen patients (13 females) were recruited (mean age 61.6 years). There was a protocol violation in one patient, who subsequently withdrew from the study due to gastrointestinal side effects. There was statistically significant (p 0.05). There were no statistically significant treatment effects on any of the five neuropsychological tests, except for digit span at 12 weeks (higher by 0.5 digits in favour of placebo, 95% CI 0.1 to 0.9). Gastrointestinal side effects occurred most frequently, affecting 13/18 subjects (72%), and were the cause of study discontinuation in one subject. Nightmares and vivid dreams occurred in 8/18 subjects (44%), and were statistically more frequent during treatment with donepezil. CONCLUSIONS: In this small study, there was no statistically significant treatment effect of donepezil on the primary outcome measure (MMSE score at 12 weeks) in PCA patients, who appear to be particularly susceptible to the development of nightmares and vivid dreams when treated. TRIAL REGISTRATION: Trial registration: Current Controlled Trials ISRCTN22636071 . Retrospectively registered 19 May 2010

Evaluating the effects of the novel GLP-1 analogue liraglutide in Alzheimer's disease:Study protocol for a randomised controlled trial (ELAD study)

Background: Liraglutide is a glucagon-like peptide-1 (GLP-1) analogue currently approved for type 2 diabetes and obesity. Preclinical evidence in transgenic models of Alzheimer's disease suggests that liraglutide exerts neuroprotective effects by reducing amyloid oligomers, normalising synaptic plasticity and cerebral glucose uptake, and increasing the proliferation of neuronal progenitor cells. The primary objective of the study is to evaluate the change in cerebral glucose metabolic rate after 12 months of treatment with liraglutide in participants with Alzheimer's disease compared to those who are receiving placebo. Methods/design: ELAD is a 12-month, multi-centre, randomised, double-blind, placebo-controlled, phase IIb trial of liraglutide in participants with mild Alzheimer's dementia. A total of 206 participants will be randomised to receive either liraglutide or placebo as a daily injection for a year. The primary outcome will be the change in cerebral glucose metabolic rate in the cortical regions (hippocampus, medial temporal lobe, and posterior cingulate) from baseline to follow-up in the treatment group compared with the placebo group. The key secondary outcomes are the change from baseline to 12 months in z scores for clinical and cognitive measures (Alzheimer's Disease Assessment Scale - Cognitive Subscale and Executive domain scores of the Neuropsychological Test Battery, Clinical Dementia Rating Sum of Boxes, and Alzheimer's Disease Cooperative Study - Activities of Daily Living) and the incidence and severity of treatment-emergent adverse events or clinically important changes in safety assessments. Other secondary outcomes are 12-month change in magnetic resonance imaging volume, diffusion tensor imaging parameters, reduction in microglial activation in a subgroup of participants, reduction in tau formation and change in amyloid levels in a subgroup of participants measured by tau and amyloid imaging, and changes in composite scores using support machine vector analysis in the treatment group compared with the placebo group. Discussion: Alzheimer's disease is a leading cause of morbidity worldwide. As available treatments are only symptomatic, the search for disease-modifying therapies is a priority. If the ELAD trial is successful, liraglutide and GLP-1 analogues will represent an important class of compounds to be further evaluated in clinical trials for Alzheimer's treatment. Trial registration: ClinicalTrials.gov, NCT01843075. Registration 30 April 2013

Herpes simplex virus and rates of cognitive decline or whole brain atrophy in the Dominantly Inherited Alzheimer Network.

OBJECTIVE: To investigate whether herpes simplex virus type 1 (HSV-1) infection was associated with rates of cognitive decline or whole brain atrophy among individuals from the Dominantly Inherited Alzheimer Network (DIAN). METHODS: Among two subsets of the DIAN cohort (age range 19.6-66.6 years; median follow-up 3.0 years) we examined (i) rate of cognitive decline (N = 164) using change in mini-mental state examination (MMSE) score, (ii) rate of whole brain atrophy (N = 149), derived from serial MR imaging, calculated using the boundary shift integral (BSI) method. HSV-1 antibodies were assayed in baseline sera collected from 2009-2015. Linear mixed-effects models were used to compare outcomes by HSV-1 seropositivity and high HSV-1 IgG titres/IgM status. RESULTS: There was no association between baseline HSV-1 seropositivity and rates of cognitive decline or whole brain atrophy. Having high HSV-1 IgG titres/IgM was associated with a slightly greater decline in MMSE points per year (difference in slope - 0.365, 95% CI: -0.958 to -0.072), but not with rate of whole brain atrophy. Symptomatic mutation carriers declined fastest on both MMSE and BSI measures, however, this was not influenced by HSV-1. Among asymptomatic mutation carriers, rates of decline on MMSE and BSI were slightly greater among those who were HSV-1 seronegative. Among mutation-negative individuals, no differences were seen by HSV-1. Stratifying by APOE4 status yielded inconsistent results. INTERPRETATION: We found no evidence for a major role of HSV-1, measured by serum antibodies, in cognitive decline or whole brain atrophy among individuals at high risk of early-onset AD

Neurosyphilis in patients with HIV

Syphilis is a resurgent sexually transmitted infection in the UK that is disproportionately diagnosed in patients living with HIV, particularly in men who have sex with men. Syphilis appears to present differently in patients with HIV, particularly in those with severe immunosuppression. Progression to neurosyphilis is more common in HIV coinfection and can be asymptomatic, often for several years. The presentations of neurosyphilis vary but can include meningitis, meningovascular disease, general paresis and tabes dorsalis. There is debate about the circumstances in which to perform a lumbar puncture, and the current gold standard diagnostics have inadequate sensitivity. We recommend a pragmatic approach to lumbar punctures, interpreting investigations and deciding when to consider treatment with a neuropenetrative antibiotic regimen

Sporadic CJD in association with HIV

Background Creutzfeldt-Jakob disease (CJD) is a rapidly progressive fatal neurodegenerative disorder. We report an unusual case of pathologically confirmed sporadic CJD developing in a HIV-positive patient but presenting with clinical and radiological features suggestive of variant CJD. Case presentation A 63-year-old man with chronic stable HIV developed progressive difficulties with decision-making, obsessive compulsive disorder and visual hallucinations over 3 months. CSF examination detected a weakly positive 14-3-3 protein, elevated S-100 protein, and siginificantly elevated total-Tau protein. Brain MRI revealed bilateral abnormal signal within the posterolateral thalami compatible with pulvinar sign. Further investigations revealed a negative tonsillar biospy and positive blood test consistent with variant CJD. However, prion protein genotyping detected MV heterozygosity at codon 129 and post-mortem histopathological examination was consistent with sporadic CJD. Conclusion Although MRI findings were suggestive of variant CJD, the short residence in the UK and MV heterozygosity are aytpical, and the histopathological examination was consistent with sporadic CJD. With only two cases of HIV and sporadic CJD reported so far, the association of CJD with HIV remains unclear

Tracking atrophy progression in familial Alzheimer's disease: a serial MRI study.

BACKGROUND: Serial MRI scanning of autosomal dominant mutation carriers for Alzheimer's disease provides an opportunity to track changes that could predate symptoms or clinical diagnosis of the disease. We used hierarchical modelling to assess how hippocampal and whole-brain volumes change as familial Alzheimer's disease progresses from the presymptomatic stage through to diagnosis. METHODS: Nine mutation carriers had serial clinical assessments and volumetric MRI scans (41 scans: range 3-8 per patient) at different clinical stages (presymptomatic, mild cognitive impairment, or clinical Alzheimer's disease). 25 healthy controls had serial scanning (54 scans: range 2-4 per patient) for comparison. We measured whole brain and total hippocampal volumes using semi-automated techniques, and adjusted for total intracranial volume. Hierarchical models were developed to estimate differences in volume and atrophy rate between mutation carriers and controls in relation to when the disease was clinically diagnosed. FINDINGS: Mutation carriers had significantly increased hippocampal and whole-brain atrophy rates compared with controls and these differences increased with time. Differences in hippocampal and whole-brain atrophy rates between controls and mutation carriers were evident 5.5 and 3.5 years, respectively, before diagnosis of Alzheimer's disease. At a cross-sectional level, differences in mean hippocampal volume between mutation carriers and controls became significant 3 years before clinical diagnosis, whereas differences in mean brain volumes became significant only 1 year before diagnosis. INTERPRETATION: Structural changes can be seen on MRI scans that predate the clinical onset of familial Alzheimer's disease. Longitudinal measures of atrophy rates can identify differences between mutation carriers and controls 2-3 years earlier than cross-sectional volumetric measures