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A jejunal adenocarcinoma is a rare form of cancer that is difficult to diagnose due to its vague and non-specific symptoms, often leading to delayed treatment and poor outcomes. In this case, we report a 43-year-old male who presented with acute abdominal pain, weight loss, and melena. A CT scan revealed a mass in the small intestine, and subsequent exploratory laparotomy confirmed the presence of a tumor, which was surgically excised. Histopathological analysis confirmed jejunal adenocarcinoma with positive CDX2 staining, ruling out other adenocarcinoma subtypes. This case underscores the importance of including jejunal adenocarcinoma in differential diagnoses of acute abdomen and highlights the critical role of early surgical intervention in improving patient outcomes.
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OBJECTIVE: To explore the oral health-related quality of life and its possible risk factors among adults with Osteogenesis Imperfecta using the Oral Health Impact Profile (OHIP)-49 questionnaire. Secondary objectives were to investigate the impact of self-reported Osteogenesis Imperfecta, Dentinogenesis Imperfecta, and age on various dental parameters. MATERIALS AND METHODS: A cross-sectional questionnaire was distributed online to 417 Dutch adults with Osteogenesis Imperfecta at three national referral centers. Multivariate linear regression was performed to identify indicators for OHIP-49 Scores. The effect of Osteogenesis Imperfecta, Dentinogenesis Imperfecta, and age on various dental parameters was investigated using logistic regressions (p < 0.05). RESULTS: One hundred and fifty-five questionnaires (37.2%) were suitable for analysis. Osteogenesis Imperfecta type III was significantly associated with higher OHIP-49 scores as compared to type I. Symptoms of temporomandibular disorders, missing teeth or dentures also increased the OHIP-49 scores significantly. Osteogenesis Imperfecta type IV and increasing age were associated with missing teeth. There was a 31.94 times (95% CI: 8.56-119.13) higher odds of tooth fracture with self-reported Dentinogenesis Imperfecta. CONCLUSIONS: Adults with Osteogenesis Imperfecta type III report a lower oral health-related quality of life compared to Osteogenesis Imperfecta type I adults.
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Biallelic pathogenic variants in UQCRFS1 underlie a rare form of isolated mitochondrial complex III deficiency associated with lactic acidosis and a distinctive scalp alopecia previously described in two unrelated probands. Here, we describe a participant in the Undiagnosed Diseases Network (UDN) with a dual diagnosis of two autosomal recessive disorders revealed by genome sequencing: UQCRFS1-related mitochondrial complex III deficiency and GJA8-related cataracts. Both pathogenic variants have been reported before: UQCRFS1 (NM_006003.3:c.215-1 G>C, p.Val72_Thr81del10) in a case with mitochondrial complex III deficiency and GJA8 (NM 005267.5:c.736 G>T, p.Glu246*) as a somatic change in aged cornea leading to decreased junctional coupling. A multi-modal approach combining enzyme assays and cellular proteomics analysis provided clear evidence of complex III respiratory chain dysfunction and low abundance of the Rieske iron-sulfur protein, validating the pathogenic effect of the UQCRFS1 variant. This report extends the genotypic and phenotypic spectrum for these two rare disorders and highlights the utility of deep phenotyping and genomics data to achieve diagnosis and insights into rare disease.
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Creatine transporter (CTD) and guanidinoacetate methyltransferase (GAMT) deficiencies are rare inborn errors of creatine metabolism, resulting in cerebral creatine deficiency. Patients commonly exhibit intellectual and developmental disabilities, often accompanied by behavior problems, delayed speech, seizures, and motor impairments. There is currently no efficacious treatment for CTD, while the current management for GAMT requires lifelong treatment with a protein restricted diet and intake of high amounts of oral supplements. Efforts to develop effective, sustainable treatments for these disorders are limited by the lack of clinical and patient-derived meaningful outcomes. A core outcome set (COS) can facilitate consensus about outcomes for inclusion in studies. Unfortunately, patient and caregiver perspectives have historically been overlooked in the COS development process, thus limiting their input into the outcome selection. We partnered with caregivers and health professionals to establish the first COS for CTD and GAMT. The COS developed includes seven outcomes ("Adaptive Functioning", "Cognitive Functioning", "Emotional Dysregulation", "MRS Brain Creatine", "Seizure/Convulsions", "Expressive Communication", and "Fine Motor Functions") for both CTD and GAMT, and an additional outcome for GAMT ("Serum/Plasma Guanidinoacetate") that are important to stakeholders and consequently should be considered for measurement in every clinical trial. Caregivers were valued partners throughout the COS development process, which increased community engagement and facilitated caregiver empowerment. We expect this COS will ensure a patient-centered approach for accelerating drug development for CTD and GAMT, make clinical trial results comparable, minimize bias in clinical trial outcome selection, and promote efficient use of resources.
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The mitoribosome synthesizes 13 protein subunits of the oxidative phosphorylation system encoded by the mitochondrial genome. The mitoribosome is composed of 12S rRNA, 16S rRNA and 82 mitoribosomal proteins encoded by nuclear genes. To date, variants in 12 genes encoding mitoribosomal proteins are associated with rare monogenic disorders, and frequently show combined oxidative phosphorylation deficiency. Here, we describe five unrelated individuals with biallelic variants in the DAP3 nuclear gene encoding mitoribosomal small subunit 29 (MRPS29), with variable clinical presentations ranging from Perrault syndrome (sensorineural hearing loss and ovarian insufficiency) to an early childhood neurometabolic phenotype. Assessment of respiratory chain function and proteomic profiling of fibroblasts from affected individuals demonstrated reduced MRPS29 protein levels, and consequently decreased levels of additional protein components of the mitoribosomal small subunit, associated with a combined complex I and IV deficiency. Lentiviral transduction of fibroblasts from affected individuals with wild-type DAP3 cDNA increased DAP3 mRNA expression, and partially rescued protein levels of MRPS7, MRPS9 and complex I and IV subunits, demonstrating the pathogenicity of the DAP3 variants. Protein modelling suggested that DAP3 disease-associated missense variants can impact ADP binding, and in vitro assays demonstrated DAP3 variants can consequently reduce both intrinsic and extrinsic apoptotic sensitivity, DAP3 thermal stability and DAP3 GTPase activity. Our study presents genetic and functional evidence that biallelic variants in DAP3 result in a multisystem disorder of combined oxidative phosphorylation deficiency with pleiotropic presentations, consistent with mitochondrial dysfunction.
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This paper describes the founding of the SLC6A1 Connect organization, which offers resources to patients and families with SLC6A1 diagnoses while keeping current with a scientific overview of the disorder. Following the birth of her two lovely twins, Amber Freed noticed how her son, Maxwell, missed motor development milestones and would often stare. Eventually, these signs led to a diagnosis of an SLC6A1 variant. The SLC6A1 gene is located on the short arm of chromosome 3 and the gene encodes for the gamma-aminobutyric acid (GABA) transporter 1 (GAT-1) protein. This transporter is responsible for the reuptake of the inhibitory neurotransmitter, GABA. The transporter usually removes GABA from the synapse space between two neurons, limiting over-excitability in the brain, which can lead to seizures and motor deficits as Amber noticed in her son, Maxwell. Amber realized that there were nearly no treatment options for her son's condition so she began forming connections with scientists and doctors. Initially, she flew to see Dr. Steven Gray, with whom she developed a research plan for a gene replacement therapy to treat the variant along with a design for a clinical trial. Not only this but they needed to raise four million dollars to fund these endeavors. Freed founded the SLC6A1 Connect organization to raise money and awareness and put together a network of dedicated researchers and families. Since then, the organization has raised over two million dollars and grown to offer families a base of support. The organization even hosts a yearly symposium with families, scientists, and biotech or pharmaceutical companies worldwide. In addition, we detail how the organization now offers informational resources to families to help them understand the science behind the variant and ways to help their children such as registry links and genetic testing options. These endeavors have led the organization to collaborate with scientists based on institutions such as Vanderbilt University Medical Center, UT Southwestern Medical Center, the Cleveland Clinic, and many industrial pharmaceutical partners.
Efforts of SLC6A1 Connect in providing educational, scientific, and support focused resources for those in the community SLC6A1 Connect offers many resources that patients and families afflicted by the SLC6A1 mutation benefit from. This mutation prevents a transporter from being encoded which typically allows for the proper levels of GABA in the brain to be maintained. Without this protein, there is a lack of GABA regulation and the brain is too excitable leading to seizures and motor delays. On our website, families are able to access scientific summaries of relevant publications in the field and can find plain-language summaries of the science behind the mutation. Additionally, symposiums are held once a year to allow families to hear from experts in the field and directly engage with them by asking questions. We aim to make scientific findings more understandable and accessible. The organization also allows them to become directly involved in the research, development, and medical treatment processes. Parents are able to help raise money through fundraising initiatives and receive regular information about genetic testing & registry programs. Overall, these organizational offerings have greatly benefited pediatric SLC6A1 patients, as seen through the patient family testimonies of Ms. Freed and the Fry family. Overall, throughout this paper we detail the resources made available to researchers, physicians, and families in the SLC6A1 Community.
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Rare diseases affect almost 500 million people globally, predominantly impacting children and often leading to significantly impaired quality of life and high treatment costs. While significant contributions have been made to develop effective treatments for those with rare diseases, more rapid drug discovery strategies are needed. Therapeutic antisense oligonucleotides can modulate target gene expression with high specificity through various mechanisms determined by base sequences and chemical modifications; and have shown efficacy in clinical trials for a few rare neurological conditions. Therefore, this review will focus on the applications of antisense oligonucleotides, in particular splice-switching antisense oligomers as promising therapeutics for rare neurological diseases, with key examples of Duchenne muscular dystrophy and spinal muscular atrophy. Challenges and future perspectives in developing antisense therapeutics for rare conditions including target discovery, antisense chemical modifications, animal models for therapeutic validations, and clinical trial designs will also be briefly discussed.
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Spinal muscular atrophy (SMA) is a rare inherited autosomal recessive progressive disease of a varying phenotype, with varying clinical symptoms, and as a result the patients suffering from it require multiple types of care. It was deemed useful to conduct a systematic literature review on the pharmacoeconomic evaluations of all currently registered disease-modifying therapies in order to inform policy and highlight research gaps. Pharmacoeconomic analyses written in English and published after 2016 were considered for inclusion. PubMed/Medline, Global Health and Embase were systematically and separately searched between 16 October and 23 October 2023. Hand-searching was also conducted on PubMed based on reference lists of published literature. After the exclusion criteria were applied, 14 studies were included. BMJ checklist was used for quality assessment and the Consolidated Health Economic Evaluation Reporting Standards (CHEERS) checklist was used to assess the quality of reporting of all included studies. Data extraction was performed manually. Regarding evidence synthesis, data were heterogeneous and are thus presented based on comparison. This study confirms the need for pharmacoeconomic analyses (cost-effectiveness or cost-utility) also in cases when the cost of treatment is very high and the incremental cost-effectiveness ratio values exceed the usual, acceptable values for standard therapy. Specific willingness to pay thresholds for orphan medicines are of the utmost importance, to allow patients with SMA to have access to safe and effective treatments. With such economic evaluations, it is possible to compare the value of medications with the same indication, but it should be emphasized that in the interpretation of data and in making decisions about the use of medicines, the impact of new knowledge should be considered.
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Objectives: This study aims to determine clusters of access to healthcare among adults with rare diseases in Switzerland, identify associated individual characteristics of access, and impact on health-related quality of life (HRQoL). Methods: Swiss adults (N = 341) diagnosed with a rare disease completed an online survey including the Perception of Access to Healthcare Questionnaire (PAHQ) and Short Form Health Survey (SF-12). We employed partition around medoids algorithm to identify patient clusters based on the PAHQ. Various sociodemographic/disease-related factors and HRQoL were assessed. Results: We identified two patient clusters: higher (n = 227) and lower access (n = 114). Significantly associated with lower access were an unstable disease course (p < 0.05), increased number of misdiagnoses (p < 0.05), and diseases affecting the nervous system (p < 0.01). Membership in the lower access cluster was significantly associated with worse HRQoL (p < 0.05). Conclusion: Findings highlight the need for comprehensive assessment of healthcare access in adults with rare diseases and identifies potential targets for tailored interventions.
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Accesibilidad a los Servicios de Salud , Calidad de Vida , Enfermedades Raras , Humanos , Suiza , Masculino , Femenino , Adulto , Persona de Mediana Edad , Encuestas y Cuestionarios , Adulto Joven , Anciano , Factores SocioeconómicosRESUMEN
Many people living with a rare disease (RD) face challenges accessing timely diagnosis and disease-specific specialist care. Early health-care challenges for people living with Epidermolysis Bullosa (EB), a rare genetic disease affecting 1:20,000 individuals, can begin in the antenatal period.People living with EB in Australia have access to a government funded disease specific antenatal education and support program through the National Epidermolysis Bullosa Dressing scheme (NEBDS). This article discusses two births involving families living with EB Simplex (EBS) in regional Australia. The education and support structures implemented by the NEBDS and clinical teams are discussed in line with the Australian National Strategic Action Plan for rare diseases, and includes access to genetic diagnosis, EB education, and complex care coordination.
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Epidermólisis Ampollosa Simple , Enfermedades Raras , Humanos , Femenino , Enfermedades Raras/diagnóstico , Epidermólisis Ampollosa Simple/diagnóstico , Epidermólisis Ampollosa Simple/genética , Epidermólisis Ampollosa Simple/patología , Embarazo , Australia , Diagnóstico Prenatal , Masculino , AdultoRESUMEN
Coalition to Cure CHD2 (CCC) is a patient advocacy group dedicated to improving the lives of those affected by CHD2-related disorders (CHD2-RD) by increasing education, building community, and accelerating research to uncover a cure. CHD2 is a chromatin remodeler that was identified in 2013 as being a genetic cause for developmental and epileptic encephalopathies. Pathogenic changes in CHD2 can cause treatment-resistant epilepsy, intellectual and developmental delays, and autism, and some individuals experience neurodevelopmental regression. There are currently no targeted therapies available for CHD2-related disorders. Haploinsufficiency of CHD2 is a causative mechanism of disease for individuals with pathogenic variants (primarily truncating) in CHD2. Recently, identification of individuals with deletion of nearby gene CHASERR, a regulator of CHD2 gene expression, has established dosage sensitivity in CHD2 and solidified the CHASERR gene as a potential therapeutic target for CHD2 levels. Through collaboration with our community and our scientific advisory board, CCC has created a Roadmap to Cure CHD2 as our guide toward a targeted cure that can benefit our community, with steps including (1) identifying and defining patients, (2) developing models of CHD2, (3) studying models of CHD2, (4) testing therapies, (5) involving patients, and (6) reaching a cure. Despite some of the challenges inherent in CHD2 research including establishing animal and cellular models that recapitulate the CHD2 clinical phenotype, identifying measurable outcomes and reliable biomarkers, or testing emerging therapeutic approaches, CCC continues to engage with our community to support ongoing research that aligns with our priorities. CCC sees new and exciting opportunities for additional research that can move our community toward our common goal of a cure that will improve the lives of individuals and their families now and in the future.
A roadmap to cure disorders caused by the CHD2 and CHASERR genes Coalition to Cure CHD2 (CCC) is a nonprofit founded in October 2020 to fund research towards a cure for individuals with CHD2-related disorders. The CHD2 gene was discovered as a genetic cause for epilepsy in 2013. Individuals with CHD2 typically experience seizures that can be resistant to treatment, intellectual disability, delayed development, autism, and other symptoms. The nearby CHASERR gene has been found to regulate CHD2 and is a possible therapeutic target. Individuals with a deletion of CHASERR have been identified - these individuals have too much CHD2 and more severe symptoms. CCC has created a Roadmap to Cure CHD2 as a guide for their journey towards a targeted cure for CHD2-related disorders. The steps in the roadmap include: (1) identify and define patients, (2) develop models of CHD2, (3) study models of CHD2, (4) test therapies, (5) involve patients, (6) reach a cure. CCC has worked with CHD2 families to identify family-level priorities for therapeutic development (e.g. seizures, behavior, etc), to capture the impact of disease through qualitative research, and to collect patient health data and tissue samples for scientific analysis. The development of CHD2 models, mouse models in particular, has been challenging as the mice do not develop seizures. Additional models are underway including frogs, zebrafish, and patient-derived cells. These models have provided crucial insight into the biology of CHD2 but scientific questions remain unanswered. A variety of therapeutic approaches have been proposed including novel treatments that directly target CHD2 biology as well as the repurposing of existing FDA-approved compounds. Establishing measurable outcomes, including biomarkers, and finding treatments that can reach the brain will be important. By continuing to follow this roadmap, the CCC believes that one day there will be a cure for CHD2-related disorders.
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Achondroplasia, the most common form of inherited disproportionate short stature, is caused by mutations in the fibroblast growth factor receptor 3 gene. The typical clinical features of achondroplasia include short stature, rhizomelic disproportion, joint hyperlaxity, spinal deformity and deformity of the upper and lower limbs. The latter are among the challenges of state-of-the-art orthopaedic treatment plans and significantly contribute to the burden of the disease in individuals with achondroplasia. Multidisciplinary preoperative individual decision-making concerning surgical interventions should be considered. New medical treatments for achondroplasia have been developed and (some) have been approved for clinical use in several countries. While the number of research articles on achondroplasia is increasing rapidly, many unknown or controversial orthopaedic topics remain. Furthermore, in view of new medical developments with improvements in growth and potentially other effects, the timing and algorithms of orthopaedic treatments (e.g. guided growth, limb lengthening and deformity correction) need to be re-evaluated. While standing height is the primary research focus in medical therapy, it is crucial to comprehensively assess orthopaedic parameters in this multifactorial disease. The current treatment of patients with achondroplasia requires specialised multidisciplinary centres with transitional care and individual orthopaedic counselling.
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Advancements in sequencing technology have significantly enhanced diagnostic capabilities for rare neurological diseases. This progress in molecular diagnostics can greatly impact clinical management and facilitate the development of personalized treatments for patients with rare neurological diseases. Neurologists with expertise should raise clinical awareness, as phenotyping remains crucial for making a clinical diagnosis, even in the genomics era. They should prioritize different types of genomic tests, considering both the benefits and the limitations inherent to each test. Notably, long-read sequencing is being utilized in cases suspected to involve repeat expansion disorders or complex structural variants. Repeat expansion disorders are highly prevalent in neurological diseases, particularly within the ataxia group. Significant efforts, including periodic reanalysis, data sharing, or integration of genomics with multi-omics studies, should be directed toward cases that remain undiagnosed after standard next-generation sequencing.
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The field of rare disease therapeutics has witnessed significant growth in recent years, highlighting the need for diverse therapeutic approaches to cater to the unique needs of individuals with rare diseases. Rare disease therapies encompass a broad spectrum of interventions, including orphan medicinal products, orphan medical devices, rehabilitative therapies, and digital therapeutics, with the lines between these categories blurring. This paper covers the session of the RE (ACT)-IRDiRC Conference 2023 and delves into the landscape of orphan medical device research and development, shedding light on the challenges and opportunities in this burgeoning field. It provides a short overview of the different international legislations in the field. In addition, it highlights several exemplary orphan medical devices. The first example is an exoskeleton for boys with Duchenne Muscular Dystrophy, enabling them to maintain arm functionality and independence. Another example presented was an EEG device linked to an app detecting seizures in rare epilepsy conditions, which alerts caregivers to seizures in real-time but also facilitates objective seizure reporting for clinicians, aiding in diagnosis and treatment optimization. It also showcases the role of gamification and enabling technologies in addressing rare diseases, by showing a game designed for children with cystic fibrosis, and a telemedicine system for rehabilitation therapy. Both solutions aim to improve patients' understanding of their conditions and enhance their self-management. In conclusion, this paper underscores the critical need for patient-centric orphan and pediatric medical devices to provide therapeutic options for individuals with rare diseases. It highlights the impact of existing devices on enhancing the quality of life for rare disease patients and emphasizes the necessity for greater incentives and support for research and development in this field.
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We aimed to describe the clinical and genetic characteristics of 16 individuals with KBG syndrome (KBGS) from 13 Indian families. We retrospectively analyzed the clinical details of individuals with KBGS harboring a likely pathogenic/pathogenic variant in ANKRD11. We also analyzed their facial gestalt using Face2Gene and recorded the top three differential disorders suggested by the application. The most frequent clinical features observed in our cohort were as follows: learning and intellectual disability-14/15 (93%), skeletal abnormalities-14/15 (93%), postnatal short stature-13/15 (87%), brachydactyly-11/15 (73%), and characteristic facial appearance-13/15 (87%). We identified 12 single nucleotide variants (SNVs), including six recurrent and six novel variants, and a copy number variant in the 16q24.3 region encompassing ANKRD11 gene. The novel variants were as follows: p.(Gln1236Ter), p.(Asp884ThrfsTer93), p.(Arg1466GlyfsTer87), p.(Tyr2056Ter), p.(Leu955TrpfsTer22), and p.(Lys766ArgfsTer10). The identified SNVs in ANKRD11 clustered around exon 9. We observed a high concordance of Face2Gene in predicting KBGS.
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BACKGROUND: Patients with rare genetic diseases frequently experience significant diagnostic delays. Routinely collected data in the electronic health record (EHR) may be used to help identify patients at risk of undiagnosed conditions. Long QT syndrome (LQTS) is a rare inherited cardiac condition associated with significant morbidity and premature mortality. In this study, we examine LQTS as an exemplar disease to assess if clinical features recorded in the primary care EHR can be used to develop and validate a predictive model to aid earlier detection. METHODS: 1495 patients with an LQTS diagnostic code and 7475 propensity-score matched controls were identified from 10.5 million patients' electronic primary care records in the UK's Clinical Practice Research Datalink (CPRD). Associated clinical features recorded before diagnosis (with p < 0.05) were incorporated into a multivariable logistic regression model, the final model was determined by backwards regression and validated by bootstrapping to determine model optimism. RESULTS: The mean age at LQTS diagnosis was 58.4 (SD 19.41). 18 features were included in the final model. Discriminative accuracy, assessed by area under the curve (AUC), was 0.74, (95% CI 0.73, 0.75) (optimism 6%). Features occurring at significantly greater frequency before diagnosis included: epilepsy, palpitations, syncope, collapse, mitral valve disease and irritable bowel syndrome. CONCLUSION: This study demonstrates the potential to develop primary care prediction models for rare conditions, like LQTS, in routine primary care records and highlights key considerations including disease suitability, finding an appropriate linked dataset, the need for accurate case ascertainment and utilising an approach to modelling suitable for rare events.
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Perry disease (PeD) is a rare, neurodegenerative, genetic disorder inherited in an autosomal dominant manner. The disease manifests as parkinsonism, with psychiatric symptoms on top, such as depression or sleep disorders, accompanied by unexpected weight loss, central hypoventilation, and aggregation of DNA-binding protein (TDP-43) in the brain. Due to the genetic cause, no causal treatment for PeD is currently available. The only way to improve the quality of life of patients is through symptomatic therapy. This work aims to review the latest data on potential PeD treatment, specifically from the medicinal chemistry and computer-aided drug design (CADD) points of view. We select proteins that might represent therapeutic targets for symptomatic treatment of the disease: monoamine oxidase B (MAO-B), serotonin transporter (SERT), dopamine D2 (D2R), and serotonin 5-HT1A (5-HT1AR) receptors. We report on compounds that may be potential hits to develop symptomatic therapies for PeD and related neurodegenerative diseases and relieve its symptoms. We use Phase pharmacophore modeling software (version 2023.08) implemented in Schrödinger Maestro as a ligand selection tool. For each of the chosen targets, based on the resolved protein-ligand structures deposited in the Protein Data Bank (PDB) database, pharmacophore models are proposed. We review novel, active compounds that might serve as either hits for further optimization or candidates for further phases of studies, leading to potential use in the treatment of PeD.
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Descubrimiento de Drogas , Humanos , Descubrimiento de Drogas/métodos , Proteínas de Transporte de Serotonina en la Membrana Plasmática/metabolismo , Proteínas de Transporte de Serotonina en la Membrana Plasmática/genética , Proteínas de Transporte de Serotonina en la Membrana Plasmática/química , Trastornos Parkinsonianos/tratamiento farmacológico , Trastornos Parkinsonianos/genética , Trastornos Parkinsonianos/metabolismo , Monoaminooxidasa/metabolismo , Monoaminooxidasa/genética , Monoaminooxidasa/química , Animales , Diseño de FármacosRESUMEN
OBJECTIVES: To identify the types of disease most likely to be affected by the Institute for Clinical and Economic Review's (ICER) shared savings assumptions. METHODS: For diseases with treatments that were Food and Drug Administration approved between 2019 and 2023, annual direct and indirect economic burden and characteristics of each disease were extracted from peer-reviewed literature. ICER's shared savings methodology was applied 2 ways: 50/50 shared savings and $150 000 cost-offset cap. The primary outcome was the difference in eligible cost savings provided by a hypothetical disease cure under ICER's 2 shared savings methods. Characteristics of diseases most impacted by these 2 methods were evaluated descriptively. RESULTS: Food and Drug Administration approved 260 therapies for 89 unique diseases between 2019 and 2023. Shared savings reduced value of a hypothetical cure for hemophilia A most (50/50 method: -$367 670 per year; cap method: -$585 340 per year), followed by acute hepatic porphyria (50/50 method: -$333 948; cap method: -$517 896) and paroxysmal nocturnal hemoglobinuria (50/50 method: -$291 997; cap method: -$433 993). Compared with diseases with annual burdens <$150 000, those ≥$150 000 had earlier disease onset by 22.0 years (age 12.3 vs 34.3), lower life expectancy by 10.6 years (55.8 vs 66.4 years), and lower disease prevalence (4.7 vs 1981.5 per 100 000). Shared savings' impact on health-benefit price benchmarks was projected to be larger for diseases with shorter life expectancy (ρ = -0.319; p =.005), worse quality of life (ρ = -0.263; P =.020), and lower prevalence (ρ = -0.418; P < .001). CONCLUSIONS: ICER's shared savings assumptions would most likely have the largest negative impact on health-benefit price benchmarks for rare, severe, and pediatric diseases.