The Problem of Rarity: Estimation of Prevalence in Rare Disease.

BACKGROUND: From a disease's first description to its wider recognition, factors such as changes over time in diagnostic criteria, available therapies, and subsequent mortality rates may influence diagnosed prevalence of rare diseases. OBJECTIVES: To propose a novel methodology for estimating the true prevalence of rare diseases using current incidence adjusted to changing diagnostic practice over time. This article focuses on rare diseases whose diagnosis may have changed over time, and raises the hypothesis that prevalence calculated from current incidence may be higher than diagnosed prevalence, which may lag behind the current disease definition and diagnostic methods. A rare epileptic encephalopathy, Dravet syndrome (DS), is explored as an illustrative example. METHODS: A targeted literature review was performed for DS to identify all reported incidence, prevalence, and mortality and depict how diagnostic practice has evolved over time. A conceptual model was developed to calculate prevalence derived from current incidence figures alone (incidence-derived prevalence) or incidence adjusted with factors that cause a diagnostic drag (diagnostic awareness-adjusted prevalence). RESULTS: We identified sufficient publications of incidence and prevalence to test the conceptual model. For pediatric patients with DS, diagnosed prevalence in the field (as reported in current literature) matches incidence-derived prevalence, whereas for adult patients, it is overestimated by incidence-derived prevalence, but not by diagnostic awareness-adjusted prevalence. CONCLUSIONS: Care should be taken with current incidence-derived prevalence figures to not overstate the prevalence in rare diseases, as methodological challenges in counting small populations, coupled with advances in rare disease discovery, may cause discrepancies.

Quality of life and comorbidities associated with Dravet syndrome severity: a multinational cohort survey.

AIM: To test the hypothesis that higher seizure burden in Dravet syndrome is associated with increased comorbidities and lower quality of life (QoL) in a large cohort of patients with Dravet syndrome and their caregivers in Europe. METHOD: An extensive survey of caregivers of patients with Dravet syndrome on experiences of diagnosis, seizure burden, management, social and financial impact, and health services use was administered online in 10 languages. RESULTS: The survey received 584 unique responses from caregivers of paediatric (83%) and adult (17%) patients with Dravet syndrome (aged <1-48y). Despite broadly following current treatment guidance, less than 10% of patients were seizure free in the previous 3 months. Nearly all (99.6%) patients aged 5 years or older experienced at least one or more motor, speech, learning, or behavioural impairment. High seizure frequency was related to more reports of emergency treatment, comorbidities, and a lower QoL (as measured by the standardized instrument EQ-5D-5L). If not diagnosed at the first instance, the majority (83%) of adults, but less than 20% of 6- to 11-year-olds were diagnosed after 4 or more years. INTERPRETATION: Patients with Dravet syndrome with the highest current seizure frequency suffer from more comorbidities and have a lower QoL. Therefore, more effective antiepileptic treatments are needed. WHAT THIS PAPER ADDS: The survey captured about 15% of all patients with Dravet syndrome in Europe. Less than 10% of patients had current seizure freedom. Patients with a high current seizure burden have more comorbidities and lower quality of life.

Adherence to exercise referral schemes by participants - what do providers and commissioners need to know? A systematic review of barriers and facilitators.

BACKGROUND: Physical inactivity levels are rising worldwide with major implications for the health of the population and the prevalence of non-communicable diseases. Exercise referral schemes (ERS) continue to be a popular intervention utilised by healthcare practitioners to increase physical activity. We undertook a systematic review of views studies in order to inform guidance from the UK National Institute of Health and Care Excellence (NICE) on exercise referral schemes to promote physical activity. This paper reports on the participant views identified, to inform those seeking to refine schemes to increase attendance and adherence. METHODS: Fifteen databases and a wide range of websites and grey literature sources were searched systematically for publications from 1995 to June 2013. In addition, a range of supplementary methods including, a call for evidence by NICE, contacting authors, reference list checking and citation tracking were utilised to identify additional research. Studies were included where they detailed schemes for adults aged 19 years or older who were 'inactive' (i.e. they are not currently meeting UK physical activity guidelines). Study selection was conducted independently in duplicate. Quality assessment was undertaken by one reviewer and checked by a second, with 20 % of papers being considered independently in duplicate. Papers were coded in qualitative data analysis software Atlas.ti. This review was reported in accordance with PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement). RESULTS: Evidence from 33 UK-relevant studies identified that support from providers, other attendees and family was an important facilitator of adherence and 'making exercise a habit' post programme, as was the variety and personalised nature of sessions offered. Barriers to attendance included the inconvenient timing of sessions, their cost and location. An intimidating gym atmosphere, a dislike of the music and TV and a lack of confidence in operating gym equipment were frequently reported. CONCLUSIONS: These findings provide valuable insights that commissioners and providers should consider. The main themes were consistent across a large number of studies and further research should concentrate on programmes that reflect these findings.

Neonatal desensitization allows long-term survival of neural xenotransplants without immunosuppression.

Preclinical development of human cells for potential therapeutic application in neurodegenerative diseases requires that their long-term survival, stability and functional efficacy be studied in animal models of human disease. Here we describe a strategy for long-term immune protection of human fetal and stem cell-derived neural cells transplanted into the adult rat brain, by desensitizing the host rat to similar cells in the neonatal period, without the need for additional immunosuppression.

Caregiver impact and health service use in high and low severity Dravet syndrome: A multinational cohort study.

PURPOSE: To estimate costs associated with the current management of Dravet syndrome (DS), explore psychosocial aspects of the disease in caregivers and siblings, and identify patient characteristics associated with higher costs in a large, predominantly European survey cohort of patients and their caregivers conducted in 2016. METHODS: Health and social care resource use, productivity and quality of life (QoL) data were summarised. Costs for European five (EU5) countries (France, Germany, Italy, Spain and UK) were calculated and patients with high and low current seizure burden compared. Direct healthcare costs and out-of-pocket costs were calculated using literature reported health service costs and participant reported costs, respectively. RESULTS: Direct annual costs of management of non-seizure-related symptoms ($7929) contributed to approximately 50% of all costs (including medication). Excluding medication, non-seizure-related costs dominated costs of care. Cost for patients with high seizure burden were higher for seizure-related healthcare use and physiotherapy, but lower for other therapies. Most (80%) caregivers reported an influence on their career choices and 28% of those in work had missed over three working days in the past four weeks for emergency or routine needs of their child. Caregivers had little free time, relied on family members for support and respite, and experienced emotional stress and uncertainty about their child's future healthcare needs. CONCLUSION: Families caring for a DS patient manage considerable social and financial impacts. Total direct costs of DS patients (excluding drugs) are driven by non-seizure-related healthcare use and high seizure burden is associated with higher healthcare costs.

Comparative proteomic analysis reveals differential expression of Hsp25 following the directed differentiation of mouse embryonic stem cells.

Murine embryonic stem (ES) cells can be committed to neural differentiation with high efficiency in culture through the use of feeder- and serum-free media. This system is proving to be an excellent model to study processes involved in ES cell commitment to neural cell fate. We used this approach to generate neurogenic embryoid bodies (NEBs) in a serum-free culture system to perform proteomic analysis of soluble fractions and identify early changes in protein expression as ES cells differentiate. Ten candidate proteins were altered significantly in expression levels. One of the most significant alterations was for the small heat shock protein Hsp25. Three species of Hsp25 are detected in ES cells, and this expression pattern changes during the first 24 h of differentiation until expression is decreased to levels that are barely detectable at 4 days following differentiation. We used immunofluorescence studies to confirm that following ES cell differentiation, expression of Hsp25 becomes excluded from neural precursors as well as other differentiating cells, making it a potentially useful marker of early ES cell differentiation.

A functional domain of Dof that is required for fibroblast growth factor signaling.

Signal transduction by fibroblast growth factor (FGF) receptors in Drosophila depends upon the intracellular protein Dof, which has been proposed to act downstream of the receptors and upstream of Ras. Dof is the product of a fast-evolving gene whose vertebrate homologs, BCAP and BANK, are involved in signaling downstream of the B-cell receptor. Mapping functional domains within Dof revealed that neither of its potential interaction motifs, the ankyrin repeats and the coiled coil, is essential for the function of Dof. However, we have identified a region within the N terminus of the protein with similarity to BCAP and BANK, which we refer to as the Dof, BCAP, and BANK (DBB) motif, that it is required for FGF-dependent signal transduction and is necessary for efficient interaction of Dof with the FGF receptor Heartless. In addition, we demonstrate that Dof is phosphorylated in the presence of an activated FGF receptor and that tyrosine residues could contribute to the function of the molecule.

Patient access to reimbursed biological disease-modifying antirheumatic drugs in the European region.

Background & Objectives: Biological disease-modifying antirheumatic drugs (bDMARDs) for the treatment of rheumatoid arthritis (RA) are not always accessible to all patients in accordance with international guidelines, partly owing to their high direct costs against a background of restricted healthcare budgets. This study compares the size of RA patient populations with access to reimbursed bDMARDs across 37 European countries, Russia, and Turkey, according to their treatment eligibility defined by European League Against Rheumatism (EULAR) recommendations and national reimbursement criteria. Methods: The size of the RA patient population eligible for bDMARD treatment was estimated in a population model using published RA epidemiological data and clinical criteria defined by 2013 EULAR recommendations along with national reimbursement criteria defined in a survey of the 39 countries in November 2015. Results: According to EULAR recommendations, 32% of the total RA population in the European region is eligible for bDMARD treatment. However, only an average 59% of this EULAR-eligible population remains eligible after applying national reimbursement criteria (from 86% in 'high access' to 13% in 'low-access' countries). Conclusion: Access to reimbursed bDMARDs remains unequal in the European region. As biosimilars of bDMARDs are introduced, changes in reimbursement criteria may increase access to bDMARDs and reduce this inequality.

Ceftaroline fosamil treatment outcomes compared with standard of care among hospitalized patients with complicated skin and soft tissue infections.

AIM: Compare clinical and cost outcomes associated with ceftaroline fosamil with other commonly used antibiotics in complicated skin and soft tissue infections. METHODS: Retrospective analysis of hospital records from 2010 to 2013 in Premier's Perspective comparative database for adults with complicated skin and soft tissue infection treated with intravenous ceftaroline fosamil, vancomycin, daptomycin, linezolid or tigecycline. Length of stay, inpatient costs and mortality were compared between propensity score-matched treatment groups. RESULTS & CONCLUSION: Compared with the other commonly used antibiotics, matched patients in the ceftaroline fosamil treatment group had an equivalent (1%) or lower (compared with linezolid, 2%) in-hospital mortality rate, and significantly lower (p < 0.001) average unadjusted and regression-adjusted length of stay and inpatient costs (savings of $3398.80 compared with daptomycin).

Isolation of proteins that interact with the signal transduction molecule Dof and identification of a functional domain conserved between Dof and vertebrate BCAP.

Dof is a large molecule essential for signal transduction by the two FGF receptors in Drosophila. It contains two ankyrin repeats and a coiled-coil region, but has no other recognisable structural motif. Dof shares these features with its closest vertebrate relatives, the B-cell signalling molecules BCAP and BANK. In addition, this family of proteins shares a region of homology upstream of the ankyrin repeats, which we call the Dof/BCAP/BANK (DBB) motif. We have identified 44 proteins that interact with Dof in a yeast two-hybrid screen. These include the Drosophila FGF-receptor Heartless and Dof itself. We show that the integrity of the DBB motif is required both for Dof and for BCAP to form dimers. Analysis of the interactions between a set of deletion constructs of Dof and the panel of interactors suggests that Dof may adopt different conformations, with a folded conformation stabilized by interactions between the DBB motif and the C-terminal part of the protein.

Comparative analysis of the retinal potential of embryonic stem cells and amniotic fluid-derived stem cells.

Photoreceptors have recently been generated from mouse and human embryonic stem cells (ESCs), although ethics concerns impede their utilization for cell replacement therapy for retinal disease. Extra-embryonic tissues have received attention as alternative therapeutic sources of stem cells. Human and mouse amniotic fluid-derived stem cells (AFCs) have been reported to be multipotent and express embryonic and adult stem cell markers. Here, in vitro conditions that generate retinal cells from ESCs were used to analyze and compare the retinal potential of murine AFCs and ESCs. We show that AFCs express pluripotency markers (Nanog, Sox2, and Oct3/4) as well as retinal transcription factor genes (Et, Lhx2, Tll1, Six6, Otx2, Pax6, and Fgf15). AFCs from amniotic fluid of Fgf15.gfp, Nrl.gfp, and Crx.gfp embryos cultured in retinal proliferation and differentiation conditions failed to switch on these retinal transgenes. AFCs cultured in retinal-promoting conditions, effective on ESCs, showed reduced expression of retinal markers. Retinal co-cultures activated retinal genes in ESCs but not in AFCs, and migration assays in retinal explants showed limited migration of AFCs compared with ESCs. Unlike ESCs, AFCs do not express the early embryonic ectodermal gene Utf1 and Western analysis of AFCs identified only the B isoform of Oct3/4, rather than the isoform A present in ESCs. We conclude that AFCs have restricted potential and differ considerably from ESCs and retinal progenitor cells. Reprogramming to induce pluripotency or new differentiation protocols will be required to confer retinal potential to AFCs as expression of a subset of pluripotency and retinal markers is not sufficient.

A useful approach to identify novel small-molecule inhibitors of Wnt-dependent transcription.

The Wnt signaling pathway is frequently deregulated in cancer due to mutations in genes encoding APC, beta-catenin, and axin. To identify small-molecule inhibitors of Wnt signaling as potential therapeutics, a diverse chemical library was screened using a transcription factor reporter cell line in which the activity of the pathway was induced at the level of Disheveled protein. A series of deconvolution studies was used to focus on three compound series that selectively killed cancer cell lines with constitutive Wnt signaling. Activities of the compounds included the ability to induce degradation of beta-catenin that had been stabilized by a glycogen synthase kinase-3 (GSK-3) inhibitor. This screen illustrates a practical approach to identify small-molecule inhibitors of Wnt signaling that can seed the development of agents suitable to treat patients with Wnt-dependent tumors.

A scaleable and defined system for generating neural stem cells from human embryonic stem cells.

The ability to differentiate human ESCs (hESCs) to defined lineages in a totally controlled manner is fundamental to developing cell-based therapies and studying human developmental mechanisms. We report a novel, scaleable, and widely applicable system for deriving and propagating neural stem cells from hESCs without the use of animal products, proprietary formulations, or genetic manipulation. This system provides a definitive platform for studying human neural development and has potential therapeutic implications.