Asta Literature Retrieval: Pathophysiology and clinical mechanisms of Mitchell-Riley Syndrome. Core disease mechanisms, molecular and cellular p...

This report is retrieval-only and is generated directly from Asta results.

• Papers retrieved: 19
• Snippets retrieved: 20

Relevant Papers

[1] Molecular Genetics of Bartter Syndrome: Bridging Genotype–Phenotype Correlations and Precision Therapeutics

• Authors: Lina Zhu, Yang Li, Yiyao Bao
• Year: 2026
• Venue: Current Issues in Molecular Biology
• URL: https://www.semanticscholar.org/paper/a5e1ddccfa7d333834c4d32be123c71bfd573f83
• DOI: 10.3390/cimb48040422
• PMID: 42042082
• PMCID: 13114623
• Summary: A comprehensive framework to provide a comprehensive framework to facilitate precise diagnosis and individualized treatment strategies, ultimately advancing precision medicine in the management of Bartter syndrome is provided.
• Evidence snippets:
• Snippet 1 (score: 0.439) > Molecular genetic research on Bartter syndrome has made remarkable strides, elucidating the principal BS genes SLC12A1, KCNJ1, CLCNKB, BSND, and MAGED2 and their corresponding protein defects, thereby refining the molecular framework of disease classification while separating CaSR-associated Bartter-like disease from the core canonical BS spectrum. This progress has significantly deepened our understanding of the underlying pathophysiology and provided an essential framework for correlating genotypes with clinical phenotypes. However, the intricate relationship between genetic mutations and clinical manifestations remains complex and multifaceted, reflecting the profound heterogeneity of the syndrome. Addressing these diagnostic challenges and refining disease classification beyond traditional clinical criteria requires an integrative approach that seamlessly balances high-throughput sequencing technologies with rigorous functional studies. > The mechanisms by which these genetic mutations lead to protein dysfunction are diverse, encompassing critical defects in protein expression, impaired membrane localization, and direct functional impairments. Notably, aberrant protein folding, endoplasmic reticulum-associated degradation (ERAD), and splicing abnormalities have emerged as critical pathogenic pathways. These mechanistic insights not only enhance our fundamental understanding of the disease but also highlight highly promising therapeutic targets. While current treatments remain predominantly symptomatic, focusing primarily on managing electrolyte imbalances and associated complications, they inherently fail to address the underlying molecular defects driving the disease. > The precise identification of specific molecular defects opens innovative avenues for the development of targeted interventions aimed at correcting or compensating for specific protein abnormalities. For instance, molecular chaperones that assist in protein folding, agents that modulate aberrant splicing, and future gene-based strategies represent important experimental directions for mechanism-based therapy. Consequently, the future of Bartter syndrome management may increasingly move toward precision medicine tailored to the molecular pathology of individual patients. However, the transition from concept to clinical implementation will require substantial additional functional, translational, and trial-level evidence. Such mechanism-based strategies promise not only to alleviate clinical symptoms but to fundamentally modify disease progression, thereby drastically improving long-term prognosis and quality of life for patients.

[2] Clinical metabolomics in type 2 diabetes mellitus: from pathogenesis to biomarkers

• Authors: Chuanxin Liu, Hetao Chen, Yujin Ma, Lei Zhang, Lulu Chen et al.
• Year: 2025
• Venue: Frontiers in Endocrinology
• URL: https://www.semanticscholar.org/paper/36f8d26a208b7b96763df2e9aa3211e440031c0e
• DOI: 10.3389/fendo.2025.1501305
• PMID: 40070584
• PMCID: 11893406
• Citations: 18
• Influential citations: 1
• Summary: The results facilitate understanding the pathophysiology and mechanism of type 2 diabetes mellitus and supports research in accurate diagnosis, risk prediction, curative effect, distinct stages, and prognosis judgment of T2DM.
• Evidence snippets:
• Snippet 1 (score: 0.398) > T2DM is a chronic disease characterized by two primary pathophysiological mechanisms: ① a reduction in the mass and function of pancreatic b cells, ranging from 20% to 65%, which leads to impaired insulin secretion; ② insulin resistance, where cells in muscles, fat, and liver tissues fail to respond adequately to insulin (9). Consequently, higher levels of insulin are required to maintain normal blood glucose concentrations by inhibiting hepatic glucose production and promoting glucose uptake in muscle and adipose tissues. Prolonged exposure to elevated levels of circulating insulin leads to the development of insulin resistance in peripheral tissues, and over time, the pancreas fails to produce sufficient insulin to overcome this cellular resistance (10). However, due to the long latent period and absence of obvious symptoms initially, reversing T2DM with drug intervention is difficult after the symptoms are exposed or clinically confirmed in light of clear diagnostic criteria. According to the literature, the pathogenesis and process of metabolic syndromes such as diabetes and its complications are mainly reflected in the metabolite network, and the mechanism changes at the gene level are also found in the network. Studies have shown that some related metabolites in patients with diabetes have changed before the occurrence of obvious organic damage (11). Therefore, it is necessary to scientifically prevent T2DM in the early stages of disease onset. Fortunately, clinical metabolomics were employed to understand the progression pathologies of T2DM and its corresponding complications in detail (12). Studies have demonstrated that metabolomic analysis enables the exploration of metabolic disorders associated with T2DM, thereby deepening our understanding of disease progression (13,14). This approach has the potential to facilitate novel clinical diagnoses and the development of effective treatment strategies. Moreover, identifying specific metabolites may provide promising biomarkers for the early prediction, prevention, and management of hyperglycemia and its complications (15). In recent years, excellent progress has been made in the study of T2DM and its complications through High throughput sequencing method, i.e., a discipline specifically focused on metabolic small molecules. > Clinical metabolomics is a type of systems biology research closely linked to phenotype.
• Snippet 2 (score: 0.380) > The metabolome is sensitive to a variety of genetic and environmental stimuli and susceptible to genetic, environmental, and gut microbiome pressures, so subtle differences between individuals can lead to large perturbations in metabolite concentrations and fluxes (15, 24). At present, cystatin C has become an ideal endogenous marker for evaluating glomerular filtration function because it is not affected by sex, age or muscle mass (25). In addition, more and more evidence shows that serum CysC is involved in the pathological process of vascular remodeling and neovascularization, which is closely related to the occurrence and development of diabetic microangiopathy (26). > Eighty-four papers were included in this review and obtained through database searches, namely, PubMed, Cochrane Library, China national knowledge internet(CNKI), General Purpose, and VIP Database. The keywords for the searches were "metabolomics" and "type 2 diabetes mellitus" and its complications. The papers were incorporated by reading and summarizing the literature according to the classification standards (27). The profound analysis of clinical differential metabolites identified in type 2 diabetes and its complications were conducted concerning composition, frequency of category, sample type, and pathways to explore the pathological mechanism of type 2 diabetes and its complications to provide a systematic basis for clinical diagnosis, risk stratification, comprehending disease progression, prognosis assessment, and drug efficacy. Our goal is to apply metabolomics to clinical diagnostic biomarkers, metabolic mechanisms, and prognostic observations, and early diagnosis can be made through metabolites to avoid progression to more serious complications.

[3] Rare Monogenic Diseases: Molecular Pathophysiology and Novel Therapies

• Authors: I. Condò
• Year: 2022
• Venue: International Journal of Molecular Sciences
• URL: https://www.semanticscholar.org/paper/6aece75e6947f102b657851b74e8b96df5e654c1
• DOI: 10.3390/ijms23126525
• PMID: 35742964
• PMCID: 9223693
• Citations: 19
• Influential citations: 2
• Summary: A rare disease is defined by its low prevalence in the general population and its presence in a very small number of people.
• Evidence snippets:
• Snippet 1 (score: 0.396) > The selective expression or the particular role of specific genes in a single tissue explains the appearance of organ-specific inherited diseases. This is the case of genetic disorders of the kidney, which include dominant and recessive forms of cystic diseases, and renal tubulopathies. Mutations in polycystin-1 (PKD1) or -2 (PKD2) genes lead to autosomaldominant polycystic kidney disease (ADPKD), whose gender-dependent phenotype was analyzed in the study by Talbi et al. [9]. These results, obtained in mice lacking PKD1 expression, show the involvement of intracellular Ca2+ levels in the more severe phenotype affecting male ADPKD animals. Altogether, identification of the molecular mechanisms underlying enhanced Ca2+ signaling and proliferation in cells from male kidneys may contribute to develop novel therapeutics for ADPKD [9]. The autosomal-recessive form of polycystic kidney disease (ARPKD) mostly arises from defects in the gene named polycystic kidney and hepatic disease 1 (PKHD1), whereas a minority of cases is linked to a second causative gene DZIP1L. To examine the still unclear molecular pathophysiology of ARPKD, Cordido et al. recapitulate known molecular disease mechanisms and possible therapeutic approaches, from cellular and animal models to clinical trials [10]. The knowledge of ARPKD pathogenic pathways, involving the epidermal growth factor receptor (EGFR) axis, the production of adenylyl cyclase adenosine 3 ,5 -cyclic monophosphate (cAMP) and the activation of several protein kinases, begins to stimulate possible pharmacological interventions [10]. Inherited loss of function in various electrolyte transport proteins located along the nephron leads to two types of kidney tubulopathy with overlapping clinical symptoms: Gitelman and Bartter syndromes. The review by Nuñez-Gonzalez et al. aims to explain the different molecular basis of these difficult to diagnose monogenic syndromes. Moreover, the authors provide an overview of current therapeutic approaches and highlight the presence of common and specific options for Gitelman and Bartter patients [11].

[4] 18O-assisted dynamic metabolomics for individualized diagnostics and treatment of human diseases

• Authors: E. Nemutlu, Song Zhang, N. Juranic, A. Terzic, S. Macura et al.
• Year: 2012
• Venue: Croatian Medical Journal
• URL: https://www.semanticscholar.org/paper/880f053c7f060db4b990e447d0a22c4b69372ddb
• DOI: 10.3325/cmj.2012.53.529
• PMID: 23275318
• PMCID: 3541579
• Citations: 30
• Summary: The potential use of dynamic phosphometabolomic platform for disease diagnostics currently under development at Mayo Clinic is described and discussed briefly.
• Evidence snippets:
• Snippet 1 (score: 0.396) > Living cells represent an integrated and interacting network of genes, transcripts, proteins, small signaling molecules, and metabolites that define cellular phenotype and function. Traditionally the focus of biomedical research was on individual genes, single protein targets, single metabolites, and metabolic or signaling pathways. This "molecular reductionist" paradigm was based on the assumption that identifying genetic variations and molecular components would lead to discovery of cures for human diseases. However, most of diseases are complex and multi-factorial and the disease phenotype is determined by the alterations of multiple genes, pathways, proteins and metabolites (at cellular, tissue, and organismal levels). Therefore, an integrated "omics" approach is more viable direction for uncovering alterations in metabolic networks, disease mechanisms, and mechanisms of drug effects. > Recent advent of large-scale metabolomics and fluxomic (metabolite dynamics and metabolic flux analysis) completed the "omics revolution" (Figure 1), where genomics, transcriptomics, proteomics, metabolomics, and fluxomics all together complement phenotype determination of living organism. Such integrated "omics" cascades provide a framework for advances in system and network biology, integrative physiology, and system medicine as well as system pharmacology and regenerative medicine. Noteworthy is the "reverse omic" approach or "metabolomicsinformed pharmacogenomics, " where discovery of specific metabolite changes have led to discovery of genetic alterations (2). Therefore, bringing new "omics" technologies to clinical practice will improve disease diagnostics and treatment by targeting drugs and procedures for each unique transcriptomic and metabolomic profiles.

[5] Serum metabolomics identified specific lipid compounds which may serve as markers of disease progression in patients with Alström and Bardet-Biedl syndromes

• Authors: Krzysztof Jeziorny, Karolina Pietrowska, Julia Siemińska, E. Zmysłowska-Polakowska, A. Kretowski et al.
• Year: 2023
• Venue: Frontiers in Molecular Biosciences
• URL: https://www.semanticscholar.org/paper/1a1d29801c10582356f9813c445fa88ea892e855
• DOI: 10.3389/fmolb.2023.1251905
• PMID: 38028552
• PMCID: 10657895
• Citations: 5
• Summary: Patients with ALMS/BBS have altered lipid metabolism compared to controls or obese subjects, and as the disease progresses, they show elevated levels of lipid oxidation products, which may suggest increased oxidative stress.
• Evidence snippets:
• Snippet 1 (score: 0.388) > To date, no precise therapy has been found to inhibit the development of all components of both syndromes, and treatment is only symptomatic or targeted at particular disorders, including those of a central origin (Haws et al., 2020;Haws et al., 2021). > Due to the progressive nature of the observed symptoms, leading to shortened life expectancy of patients, it seems reasonable to look for markers of progression of ALMS and BBS syndromes. One of the promising methods may be metabolomics. > Metabolomics is a relatively new technology that enables the evaluation of metabolites-small molecules formed during metabolism, the precise identification of which provides insight into biological processes. This allows a better understanding of cellular mechanisms and links them to the phenotype of patients. > Metabolomics is gaining popularity and there are more and more attempts to demonstrate its usefulness in understanding the pathophysiology of diseases, especially rare diseases (Zmyslowska et al., 2017;Zacchia et al., 2020). > The aim of the study was to identify serum metabolites characteristic to ALMS and BBS and to correlate the identified compounds with clinical parameters and diseases progression.

[6] Exploring the molecular mechanisms of subarachnoid hemorrhage and potential therapeutic targets: insights from bioinformatics and drug prediction

• Authors: Yi Liu, Yang Zhang, Huan Wei, Li Wang, Lishang Liao
• Year: 2025
• Venue: Scientific Reports
• URL: https://www.semanticscholar.org/paper/19a91d9c8cabec6a5a186729d545077e252ecb67
• DOI: 10.1038/s41598-025-97642-8
• PMID: 40229542
• PMCID: 11997208
• Citations: 1
• Summary: The findings not only elucidate the molecular mechanisms underlying SAH but also provide robust bioinformatics and experimental evidence supporting IRN as a promising therapeutic candidate, offering novel insights for future intervention strategies in SAH.
• Evidence snippets:
• Snippet 1 (score: 0.385) > involved in SAH pathology. As a result, our understanding of the cellular composition and microenvironment in SAH remains incomplete 8 . > Advances in bioinformatics provide powerful tools to analyze large-scale gene expression data and understand complex biological processes. By integrating transcriptomic data with immune cell infiltration analysis, we can gain a deeper understanding of the molecular mechanisms underlying SAH and identify potential key genes as therapeutic targets 9,10 . Previous studies have indicated that inflammation, oxidative stress, and cell death play crucial roles in the development of SAH, processes that are often closely associated with changes in specific cell types and immune responses 11 . > The goal of this study is to explore the molecular mechanisms of SAH, with a focus on immune cell infiltration and its role in disease progression. We aim to identify key genes and signaling pathways associated with SAH and investigate potential therapeutic strategies. Specifically, we will examine Isorhynchophylline (IRN) as a potential treatment for SAH and analyze its effects on relevant targets and signaling pathways. Through a comprehensive understanding of the pathological features of SAH, this study aims to provide valuable insights into future clinical interventions and treatment strategies.

[7] Changes in Serum Proteomic Profiles at Different Stages of Pregnancy Toxemia in Goats

• Authors: M. Uzti̇mür, C. N. Ünal, Gurler Akpinar
• Year: 2025
• Venue: Journal of Veterinary Internal Medicine
• URL: https://www.semanticscholar.org/paper/4b9c488b5dbd65d7b26fd2ad9aed70e8c4b59942
• DOI: 10.1111/jvim.70139
• PMID: 40492724
• PMCID: 12150350
• Citations: 2
• Summary: Understanding the serum proteome profiles of goats with pregnancy toxemia might help identify the proteomes and pathways responsible for the development of this disease and improve diagnosis and treatment.
• Evidence snippets:
• Snippet 1 (score: 0.385) > The pathophysiology and progression of this disease are not fully understood. > Traditional biomedical research has focused on the analysis of single genes, proteins, metabolites, or metabolic pathways in diseases. This molecular reductionist approach is based on the assumption that identifying genetic variations and molecular components will lead to new treatments for diseases [13][14][15][16]. However, many diseases are complex and multifactorial, and in order to determine the phenotype of such diseases, it is necessary to understand the changes that occur in more than one gene, pathway, protein, or metabolite at the cellular, tissue, and organismal levels [17][18][19]. Therefore, in recent years, proteomics, as one field of multi-omics technologies, has helped in evaluating the complex pathogenetic mechanisms of different diseases from a broad perspective and has made substantial contributions [20,21]. In veterinary medicine, proteomic analysis of metabolic diseases such as ketosis [16], hypocalcemia [22], and fatty liver [23] in dairy cows has contributed valuable insights for the definition of new pathophysiological pathways and new diagnosis and treatment protocols for these diseases. The proteomic approach can contribute importantly to a broad and detailed understanding of the changes that occur at the organismal level associated with the increase in BHBA concentration in goats with pregnancy toxemia. Our aim was to evaluate the serum protein profiles of goats with SPT or CPT using proteomic techniques to determine the proteomic profiles of these animals and to identify the relevant pathophysiological mechanisms.

[8] Traditional Chinese Medicine Modernization in Diagnosis and Treatment: Utilizing Artificial Intelligence and Nanotechnology

• Authors: Wenqi Yu, Mengzhen Chen, X. Tan, Xi Wei, Fan Sun et al.
• Year: 2026
• Venue: MedComm
• URL: https://www.semanticscholar.org/paper/d42a462bcb3071177a45f31aa43957cc2b00a2a3
• DOI: 10.1002/mco2.70596
• PMID: 41648057
• PMCID: 12868938
• Summary: An overview of applications of AI and nanotechnology to assist TCM modernization is provided and the current challenges, clinical translation, and future perspectives of AI, TCM diagnosis, and nanotechnology are summarized.
• Evidence snippets:
• Snippet 1 (score: 0.383) > The integration of multiomics technologies such as transcriptomics, proteomics, and metabolomics enables the construction of "gene-protein-metabolite" association networks. This approach reveals key biomarkers and signaling pathways associated with specific disease phenotypes, offering novel insights for elucidating disease mechanisms and identifying potential therapeutic targets. In recent years, the combined application of multiomics and computational biology has emerged as a significant research direction for elucidating the biological basis of TCM syndromes [ 105 ]. According to TCM theory, phlegmstasis (PBS) constitutes the pathological basis of CHD. Yang et al. systematically constructed a "gene-protein-metabolite" network for CHD with PBS syndrome (CHD-PBS) by integrating transcriptomic, proteomic, and metabolomic data. Results revealed suppressed JNK/AP-1 signaling and significant abnormalities in AA metabolism in CHD-PBS patients, with core molecules including JNK1, FOS, CCL2, CXCL8, PTGS2, and CSF1. ELISA validation demonstrated that the combined CSF1 and JNK1 model exhibited the highest diagnostic efficacy (AUC > 0.93) [ 106 ]. In a study of ischemic heart failure (IHF) with Qi deficiency and blood stasis (QXXY) syndrome, researchers integrated transcriptomic, proteomic, and metabolomic data to construct a multiomics network for IHF with QXXY. This revealed that the syndrome is associated with energy metabolism disorders, chronic inflammation, and coagulation abnormalities. Key pathways include HIF-1 signaling, glycolysis, and platelet activation. High-diagnosticvalue biomarkers such as HIF-1 α, IL10, and SOD2 were identified, offering new insights into elucidating the molecular mechanisms underlying TCM syndromes [ 107 ].

[9] Investigating the role of NPR1 in dilated cardiomyopathy and its potential as a therapeutic target for glucocorticoid therapy

• Authors: Yaomeng Huang, Tongxin Li, Shichao Gao, Shuyu Li, Xiaoran Zhu et al.
• Year: 2023
• Venue: Frontiers in Pharmacology
• URL: https://www.semanticscholar.org/paper/be229f6f2059faab4c97ec0a04bd055adab9dfe1
• DOI: 10.3389/fphar.2023.1290253
• PMID: 38026943
• PMCID: 10662320
• Citations: 4
• Summary: Natriuretic peptide receptor 1 (NPR1) was identified as a core gene associated with DCM through bioinformatics analysis and led to substantial improvements in cardiac and renal function, accompanied by an upregulation of NPR1 expression.
• Evidence snippets:
• Snippet 1 (score: 0.380) > Multiple pathways and molecules are involved in this process; however, the detailed underlying mechanisms remain unclear. In recent years, with the development of high-throughput sequencing and gene chip technologies, the use of bioinformatics technology to explore the occurrence, development, and prognosis of diseases has become a hot topic for scholars worldwide (Hwang et al., 2018;Nayor et al., 2019;Rinschen et al., 2019;Sturm et al., 2019;Montaner et al., 2020). > The present study aimed to use bioinformatics technology to screen for DCM-related genes and investigate their mechanisms, with the purpose of revealing the pathogenesis of DCM and seeking treatment methods. The GSE3586 dataset, containing expression profiles related to DCM, was selected from the Gene Expression Omnibus (GEO) database. This study aimed to predict the core genes that may play crucial roles in disease progression at the molecular level through the enrichment of relevant molecular pathways associated with DCM. Furthermore, the phenotype of the core genes was validated to further support the results of the bioinformatics analysis through basic and clinical experiments. Additionally, the role of glucocorticoids in DCM treatment is discussed in this article with the purpose of providing a theoretical and experimental basis for exploring the pathogenesis of DCM and elucidating therapeutic methods. This study also provides a theoretical reference for the interpretation, early diagnosis, and treatment of DCM.

[10] Renal ciliopathies: promising drug targets and prospects for clinical trials

• Authors: L. Devlin, Praveen Dhondurao Sudhindar, J. Sayer
• Year: 2023
• Venue: Expert Opinion on Therapeutic Targets
• URL: https://www.semanticscholar.org/paper/ab2155b6e12caba53d57ac0e8ce28860d69ec9fd
• DOI: 10.1080/14728222.2023.2218616
• PMID: 37243567
• Citations: 12
• Summary: The advances in basic science and clinical research into renal ciliopathies which have yielded promising small compounds and drug targets are reviewed, within both preclinical studies and clinical trials.
• Evidence snippets:
• Snippet 1 (score: 0.376) > Although renal ciliopathies can be classified into distinct syndromes, causative mutations in genes encoding proteins involved in the primary cilium or centrosome mean they may share overlapping mechanisms of disease, which may be amenable for therapeutic intervention (Figure 2). Abnormal functioning of proteins involved in ciliogenesis, such as CEP164, can prevent proper cilia formation, which will effect a myriad of downstream ciliary signaling pathways. Additionally, mutations in genes encoding for proteins involved in cargo trafficking or regulation, such as CEP290, will have implications for signal pathway transduction, as well as mutations in components of signaling pathways themselves, such as PKD1. In regard to renal ciliopathies, abnormalities in signaling pathways such as cAMP, Shh, Wnt, mTOR, and AMPK, likely cause misoriented cellular divisions, increased proliferation, increased fluid secretion and subsequent cystogenesis, consequently leading to further kidney damage. Ciliary and centriolar proteins which have roles in DDR and cell cycle regulation may also be driving a renal cystogenesis phenotype alongside increased fibrosis and apoptosis. Increased inflammation and dysfunctional mitochondria are also byproducts of dysregulated signaling pathways have been shown to contribute to the progression of renal ciliopathies. Extensive reviews of mechanisms of renal ciliopathy diseases have recently been performed [23,24]. Importantly, due to the wide range of cellular processes that primary cilia regulate, it is likely that in each syndrome there are multiple pathogenic drivers of disease. In some ways, this is advantageous as it offers many points for potential therapeutic targets. However, the cross talk between pathways and feedback loops introduces complications of changing one pathway without negatively affecting another. Further challenges arise with core biological pathways, such as Shh signaling, in which modification in vitro may be beneficial, but systemic treatment is unrealistic due to the expected severe side effects [18,24,116].

[11] New therapeutic targets in rare genetic skeletal diseases

• Authors: M. Briggs, Peter A. Bell, M. Wright, K. A. Pirog
• Year: 2015
• Venue: Expert Opinion on Orphan Drugs
• URL: https://www.semanticscholar.org/paper/1363107f71ae6d2d60abca471cddf3da5d13644b
• DOI: 10.1517/21678707.2015.1083853
• PMID: 26635999
• PMCID: 4643203
• Citations: 39
• Influential citations: 1
• Summary: An overview of disease mechanisms that are shared amongst groups of different GSDs and potential therapeutic approaches that are under investigation are described to generate critical mass for the identification and validation of novel therapeutic targets and biomarkers.
• Evidence snippets:
• Snippet 1 (score: 0.373) > However, emerging knowledge suggests that the primary genetic defect may be less important than the cells' response to the expression of the mutant gene product [107]. Moreover, the largely overlooked response of a cell (i.e. chondrocyte) to the abnormal extracellular environment is also important for disease progression as illustrated by several GSDs discussed in this review. > It is important that 'omics'-based approaches and technologies are systematically applied to the study of rare GSDs so that definitive reference profiles and disease signatures are generated for each phenotype. These can then be used in a Systems Biology approach to identify both common and dissimilar pathological signatures and disease mechanisms. This approach is entirely dependent upon relevant in vitro and in vivo models (and also novel 'disease-mechanism phenocopies' [107]) for testing new diagnostic and prognostic tools and for determining the molecular mechanisms that underpin the pathophysiology so that effective therapeutic treatments can be developed and validated. This approach will eventually lead to personalized treatments and care strategies centred on shared disease mechanisms with the use of relevant biomarkers to monitor the efficacy of treatment and disease progression. > It is vital that all relevant stakeholders are involved from the outset in defining the appropriate outcomes of any potential therapeutic regime. The perceptions of a successful therapy can differ widely between the clinical academic community and the relevant patient-support groups and it is vital that there is engagement on all these issues. > In summary, the identification of causative genes and mutations for GSDs over the last 20 years, coupled with the generation and in-depth analysis of a plethora of relevant cell and mouse models, has derived new knowledge on disease mechanisms and suggested potential therapeutic targets. The fast-evolving hypothesis that clinically disparate diseases can share common disease mechanisms is a powerful concept that will generate critical mass for the identification and validation of novel therapeutic targets and biomarkers.

[12] Human Dermal Fibroblast: A Promising Cellular Model to Study Biological Mechanisms of Major Depression and Antidepressant Drug Response

• Authors: P. Mesdom, R. Colle, É. Lebigot, S. Trabado, Eric Deflesselle et al.
• Year: 2020
• Venue: Current Neuropharmacology
• URL: https://www.semanticscholar.org/paper/79368e365458486de96794333613c12a6063bf54
• DOI: 10.2174/1570159X17666191021141057
• PMID: 31631822
• PMCID: 7327943
• Citations: 15
• Summary: This review highlights the great and still underused potential of HDF, which stands out as a very promising tool in the understanding of MDD and AD mechanisms of action.
• Evidence snippets:
• Snippet 1 (score: 0.372) > Background: Human dermal fibroblasts (HDF) can be used as a cellular model relatively easily and without genetic engineering. Therefore, HDF represent an interesting tool to study several human diseases including psychiatric disorders. Despite major depressive disorder (MDD) being the second cause of disability in the world, the efficacy of antidepressant drug (AD) treatment is not sufficient and the underlying mechanisms of MDD and the mechanisms of action of AD are poorly understood. Objective The aim of this review is to highlight the potential of HDF in the study of cellular mechanisms involved in MDD pathophysiology and in the action of AD response. Methods The first part is a systematic review following PRISMA guidelines on the use of HDF in MDD research. The second part reports the mechanisms and molecules both present in HDF and relevant regarding MDD pathophysiology and AD mechanisms of action. Results HDFs from MDD patients have been investigated in a relatively small number of works and most of them focused on the adrenergic pathway and metabolism-related gene expression as compared to HDF from healthy controls. The second part listed an important number of papers demonstrating the presence of many molecular processes in HDF, involved in MDD and AD mechanisms of action. Conclusion The imbalance in the number of papers between the two parts highlights the great and still underused potential of HDF, which stands out as a very promising tool in our understanding of MDD and AD mechanisms of action

[13] The evolving burden of asthma and contemporary advances in management: Implications for clinical practice in Southern Africa

• Authors: A. Kiboneka
• Year: 2020
• Venue: Unknown venue
• URL: https://www.semanticscholar.org/paper/0ba536bc7dbea898dcaabe247c92c7897c7e059c
• DOI: 10.30574/wjarr.2020.8.3.0315
• Citations: 2
• Summary: The development of novel asthma phenotyping & endo typing plus better classification of patients using machine learning and big data have markedly improved asthma treatment outcomes in both children and Adults, and several research groups have developed cluster analyses of phenotypes in severe asthma.
• Evidence snippets:
• Snippet 1 (score: 0.370) > Research Program (SARP) I and II cohorts to study mechanisms differentiating severe from non-severe asthma. SARP investigators characterized severe asthma as a heterogeneous syndrome with diverse molecular, biochemical, and cellular inflammatory features and structure-function abnormalities. > Adults and children with severe asthma were further categorized by unbiased statistical methods into clusters based on distinguishing clinical features. These studies have not been done in Sub-Sahara Africa. Research performed over the past one to two decades has sought to better understand the heterogeneous clinical nature of asthma. Whereas older attempts at phenotyping asthma emphasized the duality of allergic vs. non-allergic asthma, more recent non-biased analyses have attempted to cluster patients by a multitude of possible features, including age of onset, atopy, severity of airways obstruction, and requirement for medication. Examples of these phenotypes include early-onset mild allergic asthma, later-onset asthma associated with obesity, and severe non-atopic asthma with frequent exacerbations. The elucidation of asthma phenotypes has been further refined by including information regarding pathophysiologic mechanisms present in different groups. These groups, called endo-types, include examples such as aspirin-exacerbated respiratory disease and allergic bronchopulmonary mycosis. > A phenotype covers the clinically relevant properties of the disease, but does not show the direct relationship to disease etiology and pathophysiology. Different patho-genetic mechanisms might cause similar asthma symptoms and might be operant in a certain phenotype. These putative mechanisms are addressed by the term 'endotype'. > Classification of asthma based on endo-types provides advantages for epidemiological, genetic, and drug-related studies. A successful definition of endo-types should link key pathogenic mechanisms with the asthma phenotype. Thus, the identification of corresponding molecular biomarkers for individual pathogenic-mechanism underlying phenotypes or subgroups within a phenotype is important. > The term asthma encompasses a disease spectrum with mild to very severe disease phenotypes whose traditional common characteristic is reversible airflow limitation. Unlike milder disease, severe asthma is poorly controlled by the current standard of care.

[14] Advancing the understanding of autism disease mechanisms through genetics

• Authors: L. de la Torre-Ubieta, H. Won, J. Stein, D. Geschwind
• Year: 2016
• Venue: Nature medicine
• URL: https://www.semanticscholar.org/paper/a9f29d6ab53873fd50b1e65e64cd36d9447c1a9d
• DOI: 10.1038/nm.4071
• PMID: 27050589
• PMCID: 5072455
• Citations: 767
• Influential citations: 8
• Summary: Current understanding of the genetic architecture of ASD is reviewed and genetic evidence, neuropathology and studies in model systems with how they inform mechanistic models of ASD pathophysiology are integrated.
• Evidence snippets:
• Snippet 1 (score: 0.366) > stem cell models suggest that abnormalities in neurogenesis, cell fate, neuronal morphogenesis and synaptic function contribute to the pathogenesis of ASD ( Table 2 and Supplementary Table 3). Transcriptomic studies in these models point to dysregulation in specific molecular processes that may be driving pathogenesis, including chromatin modifications, RNA-splicing, Wnt signaling and Ca 2+ signaling [96][97][98][99] . A small number of drugs, including insulin-like growth factor 1 (IGF1) and roscovitine, have been used to reverse phenotypes associated with Rett syndrome, Timothy syndrome and Phelan-McDermid syndrome (PMDS) in hiPSC models [99][100][101][102] (Table 2). Although promising, human in vitro studies using neurons derived from stem cells have focused on syndromic ASD variants, and thus, modeling of idiopathic ASD 103 and ASD-associated de novo variants will be crucial to obtain a comprehensive picture of phenotypic overlap and potential, convergent disease mechanisms. A further challenge to in vitro studies is that it is not currently certain what the most relevant cellular and physiological ASD phenotypes are that need to be modeled in vitro. > Several molecular or cellular mechanisms of ASD pathophysiology have multiple lines of supporting evidence from studies in humans or model systems ( Table 3). Most of these mechanisms are individually quite broad and considerable work is needed to refine these models to targetable molecular pathways. Furthermore, these mechanisms are not entirely distinct. Indeed, the same genes or molecular pathways contribute to several of these processes at different points during development (Fig. 2), and it is not always clear how early developmental dysfunction relates to later events. An important caveat is that we only have a limited knowledge of the specific genetic contributions to autism susceptibility,

[15] The hyperornithinemia–hyperammonemia-homocitrullinuria syndrome

• Authors: D. Martinelli, D. Diodato, Emanuela Ponzi, M. Monné, S. Boenzi et al.
• Year: 2015
• Venue: Orphanet Journal of Rare Diseases
• URL: https://www.semanticscholar.org/paper/ed033868ee677da141e5c926bc7c93cac242ea06
• DOI: 10.1186/s13023-015-0242-9
• PMID: 25874378
• PMCID: 4358699
• Citations: 96
• Influential citations: 5
• Summary: The clinical phenotype of HHH syndrome is extremely variable and its severity does not correlate with the genotype or with recorded ammonium/ornithine plasma levels, suggesting the need for a better understanding of the still unsolved pathophysiology of the disease.
• Evidence snippets:
• Snippet 1 (score: 0.365) > Although the disease responds well to treatment with low risk of relapse of hyperammonemia [38], slowly progressive pyramidal signs characterize the chronic course, as also seen in argininemia [89]. However, the mechanism(s) of pyramidal dysfunction in HHH syndrome still remains to be elucidated. Creatine deficiency may contribute to the pathogenetic mechanism of the syndrome, as creatine is relevant for mitochondrial energy metabolism, regulation of glycolysis, proteins synthesis, membrane stabilization and neuromodulation [77,78,85]. This could be in line with the finding of abnormally shaped mitochondria at electron microscopy studies in skin fibroblasts, hepatocytes and muscle biopsy from HHH syndrome patients [11,23,82]. Furthermore, a mitochondrial dysfunction has been recently related to the effects of ornithine and homocitrulline in causing oxidative stress and disturbed mitochondrial homeostasis [79,80]. > A further mechanism that can be involved in the pathophysiology of HHH syndrome is related to polyamines metabolism. Shimizu and colleagues reported increased total and fractional (putrescine, cadaverine, spermine, spermidine) polyamines in one HHH syndrome patient [30]. Indeed, the clinical similarities between HHH syndrome and argininemia, which has been associated to an abnormal polyamine metabolism [91,92], may suggest a common pathogenetic mechanism causing pyramidal dysfunction. > Overall, the pathogenesis of HHH syndrome is complex and not completely understood. It is likely that different mechanisms, including the impact of low mitochondrial ornithine on UC flux, the presence of hyperammonemic crises and the disturbance of other pathways in major organs play a role in determining the heterogeneous clinical presentation of ORC1 deficiency. > In addition, as molecular studies failed to disclose a correlation between type of mutations or ornithine transport capacity and disease severity, an effect of genetic modifiers, such as ORC genes redundancy, seems to be likely, but further studies are certainly needed to clarify this point.

[16] Therapies for Mitochondrial Disease: Past, Present, and Future

• Authors: Megan Ball, Nicole J. Van Bergen, A. Compton, David R. Thorburn, S. Rahman et al.
• Year: 2025
• Venue: Journal of Inherited Metabolic Disease
• URL: https://www.semanticscholar.org/paper/196ee50a950f29bc4134cfb8fe6bdfa9a3a1468b
• DOI: 10.1002/jimd.70065
• PMID: 40714961
• PMCID: 12301291
• Citations: 12
• Summary: The latest developments in the pursuit to identify effective treatments for mitochondrial disease are examined and the barriers impeding their success in translation to clinical practice are discussed.
• Evidence snippets:
• Snippet 1 (score: 0.364) > Mitochondrial disease is a diverse group of clinically and genetically complex disorders caused by pathogenic variants in nuclear or mitochondrial DNA‐encoded genes that disrupt mitochondrial energy production or other important mitochondrial pathways. Mitochondrial disease can present with a wide spectrum of clinical features and can often be difficult to recognize. These conditions can be devastating; however, for the majority, there is no targeted treatment. In the last 60 years, mitochondrial medicine has experienced significant evolution, moving from the pre‐molecular era to the Age of Genomics in which considerable gene discovery and advancement in our understanding of the pathophysiology of mitochondrial disease have been made. In the last decade, in response to the urgent need for effective treatments, a wide range of emerging therapies have been developed, driven by innovative approaches addressing both the genetic and cellular mechanisms underpinning the diseases. Emerging therapies include dietary intervention, small molecule therapies aimed to restore mitochondrial function, stem cell or liver transplantation, and gene or RNA‐based therapies. However, despite these advances, translation to clinical practice is complicated by the sheer genetic and clinical complexity of mitochondrial disease, difficulty in efficient and precise delivery of therapies to affected tissues, rarity of individual genetic conditions, lack of reliable biomarkers and clinically relevant outcome measures, and the dearth of natural history data. This review examines the latest developments in the pursuit to identify effective treatments for mitochondrial disease and discusses the barriers impeding their success in translation to clinical practice. While treatment for mitochondrial disease may be on the horizon, many challenges must be addressed before it can become a reality.

[17] Editorial: Impact of system biology and molecular medicine on the management of complex immune mediated respiratory diseases, volume II

• Authors: B. Cárdaba, G. Pelaia
• Year: 2023
• Venue: Frontiers in Medicine
• URL: https://www.semanticscholar.org/paper/89edb8e4f39ba41177cc4caa98150836f54e16f0
• DOI: 10.3389/fmed.2023.1187941
• PMID: 37351067
• PMCID: 10282990
• Summary: The impact of system biology and molecular medicine on the management of complex immune mediated respiratory diseases, volume II and the need for further research into this area is discussed.
• Evidence snippets:
• Snippet 1 (score: 0.361) > Complex Immune-Mediated Respiratory Diseases are highly complex and heterogeneous inflammatory disorders, sharing a common organ-disease target which is the lung, but including a broad clinical spectrum. The most frequent obstructive respiratory diseases include bronchial asthma and, chronic obstructive pulmonary disease (COPD). These disorders are characterized by airflow limitation, cough, dyspnea, chest tightness, shortness of breath, and mucus production that could be caused by numerous environmental agents, as well as, genetic, pharmacologic, physiologic, biological, or immunologic mechanisms, which give rise to distinct phenotypes, with underlying molecular mechanisms or endotypes that need to be understood. This great heterogeneity translate to a lack of good therapeutic options for an important percentage of patients that do not respond to standard treatments, who could receive relevant benefits by a precision or personalized strategy, which requires new diagnostic and therapeutic approaches. Our purpose in the second volume of this Research Topic was to collect the latest advances in the molecular and clinical characterization of these complex diseases, in order to better understand the underlying mechanisms and improve the overall management. > In this volume, five novelty works have been published: 4 original articles, 2 of them related to severe asthma, and the other 2 regarding COPD. The fifth is a mini review that summarizes the latest new advances about the T cell-mediated lung inflammation in COVID-19 infection. > In regard to bronchial asthma studies, the two published articles pursue a better understanding of underlying mechanisms of severe uncontrolled asthma, thus searching for cellular and molecular pathways involved in the pathobiology of asthmatic endotypes that do not respond to standard asthma treatments and remain uncontrolled, thereby being responsible for exacerbations and hospitalizations every year. > Asthma is a common, chronic respiratory disease, defined as "a heterogeneous disease, usually characterized by chronic airway inflammation" by the Global Initiative of Asthma (1). Despite its clinical heterogeneity, allergic mechanisms have been implicated in 50-80% of asthmatic patients and in ∼50% of severe asthma cases (2,3). Such considerations explain why there are several new biological treatments mainly directed against this subtype of inflammation (type 2 inflammation).

[18] Pathophysiology of childhood polycystic kidney diseases: new insights into disease-specific therapy

• Authors: W. Sweeney, E. Avner
• Year: 2013
• Venue: Pediatric research
• URL: https://www.semanticscholar.org/paper/7cdcda7801317bb9421bd1953219a73f8b62a435
• DOI: 10.1038/pr.2013.191
• PMID: 24336431
• PMCID: 3953890
• Citations: 59
• Influential citations: 3
• Summary: This review will focus on the molecular and cellular bases of the abnormal cystic phenotype and discuss the clinical translation of such basic data into new therapies that promise to alter the natural history of disease for children with genetic PKDs.
• Evidence snippets:
• Snippet 1 (score: 0.361) > Autosomal dominant polycystic kidney disease (ADPKD) and autosomal recessive polycystic kidney disease (ARPKD) are significant causes of morbidity and mortality in children and young adults. ADPKD, with an incidence of 1:400 to 1:1,000, affects more than 13 million individuals worldwide and is a major cause of end-stage renal disease in adults. However, symptomatic disease is increasingly recognized in children. ARPKD is a dual-organ hepatorenal disease with an incidence of 1:20,000 to 1:40,000 and a heterozygote carrier rate of 1 in 70. Currently, no clinically significant disease-specific therapy exists for ADPKD or ARPKD. The genetic basis of both ADPKD and ARPKD have been identified, and delineation of the basic molecular and cellular pathophysiology has led to the discovery that abnormal ADPKD and ARPKD gene products interact to create “polycystin complexes” located at multiple sites within affected cells. The extracellular matrix and vessels produce a variety of soluble factors that affect the biology of adjacent cells in many dynamic ways. This review will focus on the molecular and cellular bases of the abnormal cystic phenotype and discuss the clinical translation of such basic data into new therapies that promise to alter the natural history of disease for children with genetic PKDs.

[19] Modelling Mitochondrial Disease in Human Pluripotent Stem Cells: What Have We Learned?

• Authors: Cameron L. McKnight, Y. C. Low, D. Elliott, D. Thorburn, Ann E. Frazier
• Year: 2021
• Venue: International Journal of Molecular Sciences
• URL: https://www.semanticscholar.org/paper/bf41f9d980522896fcd2284bd630fbb418e55941
• DOI: 10.3390/ijms22147730
• PMID: 34299348
• PMCID: 8306397
• Citations: 21
• Summary: Mitochondrial diseases disrupt cellular energy production and are among the most complex group of inherited genetic disorders. Affecting approximately 1 in 5000 live births, they are both clinically and genetically heterogeneous, and can be highly tissue specific, but most often affect cell types with high energy demands in the brain, heart, and kidneys. There are currently no clinically validated treatment options available, despite several agents showing therapeutic promise. However, modell...
• Evidence snippets:
• Snippet 1 (score: 0.359) > Mitochondrial disease hPSC models provide a system to study disease gene-or mutation-related pathomechanisms in tissues relevant to the clinical phenotype. Ultimately, the long-term goal of these models would be to identify a phenotype in a clinically relevant cell type that could be used to validate efficacy of targeted treatments, or for use in highthroughput treatment trials [94][95][96] (Figure 2). > There are now a wide range of endpoints that have been validated in terminally differentiated cell types to investigate the underlying cellular mechanisms of disease and efficiently identify targetable pathways. Many of these approaches can also be adapted to suit different cell types and even organoids at scale. The tissue specific nature of mitochondrial diseases means that mitochondrial function post-differentiation can be distinct to that from the undifferentiated stem cells or original fibroblast line, often greatly exaggerating any underlying defects [97]. Additionally, detailed transcriptomic and proteomic analyses can elucidate cellular compensation mechanisms and potential target pathways to inform downstream treatment studies [98,99]. Other approaches include microscopic visualization of key cellular features to determine a mutation's impact on cell structure or function [100]. For cardiomyocytes and neurons, electrophysiology can provide highly sensitive data to identify even subtle functional changes [101]. Calcium imaging can be particularly informative in the context of mitochondrial diseases, since calcium handling is a key role of mitochondria [102,103].

Notes

• This provider combines search_papers_by_relevance with snippet_search.
• No synthesis or second-stage model call is performed.

Mitchell-Riley Syndrome: Comprehensive Disease Research Report

1. Disease Information

Overview. Mitchell-Riley syndrome (MRS; also called Mitchell-Riley/Martinez-Frias syndrome) is an ultra-rare, autosomal recessive multisystem disorder of endoderm-derived organ development. It is defined by a core tetrad of neonatal (permanent) diabetes mellitus, pancreatic hypoplasia (or annular pancreas), gallbladder aplasia/agenesis or hypoplasia, and duodenal and/or jejunal atresia, typically accompanied by severe protracted/chronic diarrhea and additional hepatobiliary, hematologic, and growth abnormalities (Smith et al. 2010, Nature, PMID:20148032; OMIM #615710). The disorder is caused by biallelic (homozygous or compound heterozygous) loss-of-function mutations in RFX6 (Regulatory Factor X, 6), a winged-helix transcription factor essential for pancreatic islet and gut endocrine cell development.

Key identifiers: - OMIM: #615710 (MITCHELL-RILEY SYNDROME; MTCHRS) — omim.org/entry/615710 - Gene OMIM: 612659 (REGULATORY FACTOR X, 6; RFX6) - Orphanet: ORPHA:293864 - MONDO: MONDO:0017400 - MeSH/ICD: No dedicated ICD-10/ICD-11 code exists; entries are typically coded with the components — neonatal diabetes (ICD-10 P70.2), duodenal atresia (Q41.0), gallbladder agenesis (Q44.0) - HGNC: HGNC:21478 (RFX6); NCBI Gene: 222546; chromosomal location 6q22.1 - Related/overlapping designation: Martinez-Frias syndrome (OMIM #601346) — an earlier-described, phenotypically overlapping visceral-malformation syndrome (duodenal atresia, extrahepatic biliary atresia, hypoplastic pancreas, IUGR, ± tracheoesophageal fistula/hypospadias) that was subsequently shown to be allelic to Mitchell-Riley syndrome via RFX6 mutation (research on "Martinez-Frias syndrome: Evidence of linkage to RFX6 mutation," Am J Med Genet A*). The two eponyms are now generally regarded as the same disease entity across a phenotypic spectrum, and several recent papers use the combined name "Mitchell-Riley/Martinez-Frias syndrome."

Synonyms: Mitchell-Riley syndrome; MRS; MTCHRS; Hypoplastic pancreas-intestinal atresia-hypoplastic gallbladder syndrome (NCBI GTR/UMLS C2748662); Martinez-Frias syndrome (overlapping/allelic disorder); "RFX6-related neonatal diabetes with congenital malformations."

Nature of evidence base: Information is derived almost entirely from aggregated case reports and small case series (individual patients or small consanguineous families), not large cohort registries — reflecting the disease's extreme rarity. As of the most recent comprehensive case series (Concepcion/2022 outcomes paper, PMID:35813646), roughly 16–20 genetically confirmed cases have been published worldwide since the disease's molecular description in 2010, supplemented by mechanistic data from mouse, zebrafish, human iPSC/stem-cell-derived islet, and intestinal-organoid models.

Sources: - Entry - #615710 - MITCHELL-RILEY SYNDROME; MTCHRS - OMIM - Rfx6 directs islet formation and insulin production in mice and humans - PubMed - Mitchell–Riley Syndrome: Improving Clinical Outcomes and Searching for Functional Impact of RFX-6 Mutations - PMC - Martinez-Frias Syndrome | Springer Nature Link

2. Etiology

Disease causal factor: Mitchell-Riley syndrome is a monogenic, purely genetic disorder — biallelic loss-of-function variants in RFX6, inherited in an autosomal recessive pattern. There is no known environmental, infectious, or purely mechanistic (non-genetic) causal contribution; this is a pure Mendelian disorder of endoderm organogenesis.

Genetic risk factors: - Causal variants: Homozygous or compound-heterozygous RFX6 variants — nonsense, frameshift, splice-site, and missense changes affecting the DNA-binding (winged-helix) domain or downstream dimerization/activation domains. Documented pathogenic alleles include c.1517T>G (p.Val506Gly), c.541C>T (p.Arg181Trp), c.505-2A>G (splice acceptor) + c.2782A>G (compound heterozygote), c.1153C>T (p.Arg385), and c.1129C>T (nonsense, producing a truncated protein lacking the C-terminal dimerization domain) (PMC9257252; PMC5096485; Development 2020 iPSC paper). - Consanguinity: A strong risk factor — most reported families are consanguineous (first- or third-degree relative unions), consistent with a rare autosomal recessive disease; homozygosity for the same allele is the most frequently reported genotype. - Founder/enriched alleles: The RFX6 truncating variant p.His293LeufsTer7 is markedly enriched in the Finnish population (~1:250 carrier frequency versus 0.027–0.045% in non-Finnish European gnomAD/ExAC populations, a roughly 10-fold enrichment attributable to the Finnish population bottleneck) (RFX6 haploinsufficiency paper, PMID:38743124). This allele in the heterozygous state is more relevant to MODY/T2D risk (see below) than to biallelic Mitchell-Riley syndrome, but establishes that RFX6 carrier frequency is population-stratified. - Modifier/allelic-series relationship: RFX6 is a genuinely allelic-series gene — biallelic severe (null) variants cause Mitchell-Riley syndrome; biallelic hypomorphic/missense variants can cause a milder syndromic or non-syndromic childhood-onset diabetes without the full visceral-malformation phenotype (Patel et al., Eur J Hum Genet, PMID:26264437: "Biallelic RFX6 mutations can cause childhood as well as neonatal onset diabetes mellitus"); and heterozygous RFX6 protein-truncating variants cause a distinct, reduced-penetrance MODY phenotype (~27% penetrance by age 25, versus 70% for HNF1A-MODY and 55% for HNF4A-MODY) (PMID:29026101; PMID:38743124 — haploinsufficiency shown to impair SC-islet beta-cell maturation, calcium signaling, and insulin secretion by ~54–62%). Common/non-coding RFX6 variants are additionally associated with garden-variety type 2 diabetes* risk in GWAS. - No specific environmental exposures, teratogens, maternal illness, or infections have been implicated as causal or contributory in any reported case.

Protective factors: None specifically described; there is no reported protective genetic variant or environmental exposure literature specific to RFX6/Mitchell-Riley syndrome (unlike common T2D, where protective RFX6 alleles have not been separately characterized in the literature retrieved).

Gene-environment interactions: None reported — the severe biallelic phenotype is fully genetically determined; disease severity/survival is modulated by postnatal clinical management (nutrition, transplantation) rather than by environmental causal interaction with genotype.

Suggested ontology terms: MONDO:0017400 (disease); HGNC:21478 / NCBI Gene:222546 (RFX6); inheritance — HP:0000007 (Autosomal recessive inheritance); GENO term for biallelic/homozygous genotype.

Sources: - Rfx6 directs islet formation and insulin production in mice and humans - PubMed - Biallelic RFX6 mutations can cause childhood as well as neonatal onset diabetes mellitus - PubMed - Heterozygous RFX6 protein truncating variants are associated with MODY with reduced penetrance - PubMed - RFX6 haploinsufficiency predisposes to diabetes through impaired beta cell function - PMC

3. Phenotypes

The clinical picture is a multisystem endodermal-organ malformation/functional-deficiency syndrome. Phenotypes below are organized by category with onset, severity/frequency, and suggested HPO terms (IDs given where high-confidence; all should be re-verified against the current HPO release before KB entry).

Severity/progression: Phenotype severity is highly variable across the allelic spectrum — from lethal multi-organ failure in the neonatal period (historically the majority outcome — "seven of twelve homozygous cases died of sepsis and liver failure before age 6 months," per the largest outcomes series) to long-term survivors (now into the second decade of life) under aggressive multidisciplinary management. Diabetes is permanent and progressive by definition (no remission); GI/hepatobiliary disease is generally most severe in infancy, and some patients (e.g., Patient 1 in the 2022 outcomes series) achieve discontinuation of parenteral nutrition and tolerate a normal diet by age 1.

Quality of life impact: Not formally measured with standardized instruments (EQ-5D/SF-36) in any retrieved study — this is a neonatal/pediatric multisystem disease and QoL burden is described narratively: chronic parenteral-nutrition dependency, recurrent hospitalizations, transplant burden, and lifelong intensive diabetes management dominate the clinical course. No disease-specific QoL data were found.

Sources: - Mitchell–Riley Syndrome: Improving Clinical Outcomes and Searching for Functional Impact of RFX-6 Mutations - PMC - Entry - #615710 - MITCHELL-RILEY SYNDROME; MTCHRS - OMIM Clinical Synopsis - A Newly-Discovered Mutation in the RFX6 Gene of the Rare Mitchell-Riley Syndrome - PMC

4. Genetic/Molecular Information

Causal gene: RFX6 (Regulatory Factor X, 6); HGNC:21478; NCBI Gene:222546; OMIM *612659; chromosome 6q22.1; 19 exons spanning ~52.6 kb genomic DNA; encodes a 928-amino-acid, ~102.5 kDa protein.

Protein structure/domains: RFX6 is a member of the RFX family of winged-helix DNA-binding transcription factors, closely related to RFX4. It contains an N-terminal RFX-type winged-helix DNA-binding domain (InterPro IPR003150 / Pfam PF02257) that binds "X-box" cis-regulatory promoter elements, plus C-terminal dimerization/activation domains through which it heterodimerizes with RFX3 to regulate target-gene transcription (RFX6 GeneCards; Development 2010, PMID:20040488, "Rfx6 is an Ngn3-dependent winged helix transcription factor required for pancreatic islet cell development").

Pathogenic variant classes reported: - Nonsense/frameshift (protein-truncating): e.g., c.1153C>T (p.Arg385); c.1129C>T (truncation removing the C-terminal dimerization domain, "complete loss of functional protein"; Development 2020 iPSC study) - Missense (in/near the DNA-binding domain): e.g., c.541C>T (p.Arg181Trp); c.1517T>G (p.Val506Gly) — both shown functionally to abolish transactivation of the insulin promoter and to fail to induce L-type calcium-channel genes, despite retaining normal nuclear localization (PMC9257252) - Splice-site variants: e.g., c.505-2A>G (splice-acceptor loss), reported in compound heterozygosity with a missense allele (c.2782A>G) - Genotype-phenotype correlation is imperfect but biallelic complete loss-of-function (null/null) genotypes trend toward the most severe, classic Mitchell-Riley phenotype and highest infant mortality, while hypomorphic/missense* genotypes can present with a milder, later-onset (childhood) diabetes phenotype without the full visceral malformation tetrad (PMID:26264437).

ACMG classification: Loss-of-function RFX6 alleles reported in Mitchell-Riley syndrome are generally classified pathogenic/likely pathogenic in ClinVar under an autosomal recessive mechanism (e.g., ClinVar VCV000000816, VCV000217990, VCV000393396, VCV000089376 entries for RFX6). Heterozygous truncating variants are separately catalogued as pathogenic for MODY with reduced penetrance.

Population allele frequency: RFX6 protein-truncating variants (PTVs) are present in gnomAD/ExAC at ~0.027–0.045% allele frequency in non-Finnish Europeans; the Finnish-enriched allele p.His293LeufsTer7 reaches ~1:250 carrier frequency in Finland (approximately 10-fold enrichment) (PMID:38743124). No population has been reported with elevated biallelic Mitchell-Riley syndrome incidence outside of consanguineous kindreds, but the Finnish PTV enrichment theoretically elevates regional biallelic risk.

Somatic vs. germline: Exclusively germline — no somatic mosaicism or acquired RFX6 mutation mechanism has been reported for this syndrome (distinct from RFX6's separately studied role as a tumor suppressor/oncogenic modifier in sporadic gastric and colorectal cancer — see Mechanism/Cancer note below).

Functional consequence: Loss of function (complete loss for null alleles; partial loss/hypomorphic for missense and heterozygous PTV alleles — i.e., haploinsufficiency for MODY-associated heterozygotes, shown experimentally to reduce RFX6 protein ~54% and impair SC-islet beta-cell maturation and glucose-stimulated insulin secretion by 54–62%, PMID:38743124).

Modifier genes: None specifically established for Mitchell-Riley syndrome severity; RFX6 itself sits within a broader islet-transcription-factor network (NEUROG3 upstream; PDX1, NKX6.1, NEUROD1 as co-regulated/downstream factors), any of which could in principle modify phenotype but this has not been formally studied in patients.

Epigenetics: No disease-specific DNA methylation/histone modification data were identified for Mitchell-Riley syndrome. (RFX6 itself functions partly via chromatin-level gene activation/repression — transcriptomic studies in iPSC models show RFX6 both activates pancreatic-endoderm genes and represses competing mesoderm-lineage gene programs, implying a dual activator/repressor chromatin role — Development 2020 iPSC paper.)

Chromosomal abnormalities: No aneuploidy, translocation, or copy-number-variant mechanism has been reported; disease-causing lesions are point mutations/small indels within RFX6, not large structural rearrangements.

Suggested ontology terms: HGNC:21478 (RFX6); GO:0003677 (DNA binding), GO:0000981 (DNA-binding transcription factor activity, RNA polymerase II-specific); functional_impact_category = LOSS_OF_FUNCTION (null alleles) or PARTIAL_LOSS_OF_FUNCTION (missense/hypomorphic).

Sources: - Entry - *612659 - REGULATORY FACTOR X, 6; RFX6 - OMIM - RFX6 gene Regulatory Factor X6 - GeneCards - Rfx6 is an Ngn3-dependent winged helix transcription factor required for pancreatic islet cell development - PMC - Mitchell-Riley syndrome iPSCs exhibit reduced pancreatic endoderm differentiation due to a mutation in RFX6 - Development - RFX6 haploinsufficiency predisposes to diabetes through impaired beta cell function - PMC - Heterozygous RFX6 protein truncating variants are associated with MODY with reduced penetrance - PubMed

5. Environmental Information

No environmental toxin, radiation, occupational exposure, lifestyle factor (maternal smoking/alcohol/diet), or infectious agent has been implicated as a cause, trigger, or modifier of Mitchell-Riley syndrome in the retrieved literature. This is consistent with the disease's status as a fully penetrant Mendelian recessive developmental disorder driven by biallelic RFX6 loss of function. No CTD, TOXNET, or infectious-disease-database associations were found. This section is therefore not applicable beyond noting the absence of evidence for environmental contribution.

6. Mechanism / Pathophysiology

Overview of the causal chain: RFX6 acts as a master transcriptional regulator of endoderm-derived neuroendocrine and epithelial-organ development, operating downstream of NEUROG3 (Ngn3) in the pancreatic/intestinal endocrine progenitor program, and upstream of/parallel to PDX1, NKX6.1, and NEUROD1. Biallelic loss of RFX6 function produces a multi-organ failure of endoderm patterning and cell-type specification:

1. Endoderm patterning defect (earliest step). In human iPSC and organoid models, RFX6 is required at the primitive gut tube stage for correct anteroposterior endoderm patterning; RFX6 loss disrupts duodenal identity specification upstream of PDX1 and causes intestinal patterning/heterotopic gastric mucosa (biorxiv/organoid studies: "Human organoid modeling of congenital malformations caused by RFX6 mutations reveal an essential role for this transcription factor in establishing and maintaining duodenal identity upstream of PDX1"; Development "RFX6 regulates human intestinal patterning and function upstream of PDX1").
2. Pancreatic endoderm specification failure. Patient iPSC-derived cells generate definitive endoderm and primitive gut tube normally, but fail to efficiently generate PDX1+/SOX9+ pancreatic endoderm from approximately day 8 of differentiation onward — "loss of RFX6 resulted in significantly reduced expression of PDX1 and SOX9" (Development 2020, PMID pending verification). Transcriptomically, RFX6 simultaneously activates pancreatic-program genes and represses competing mesoderm-lineage (cardiac/skeletal/muscle) transcriptional programs — a dual gatekeeper function for endoderm lineage commitment.
3. Endocrine progenitor/islet-cell differentiation block. Downstream of NEUROG3, RFX6 is required to direct differentiation of all major islet endocrine cell types except pancreatic-polypeptide cells. In Rfx6-null mice, homozygous animals fail to generate alpha, beta, delta, or epsilon cells and die shortly after birth of severe hyperglycemia (Smith et al. 2010, Nature, PMID:20148032; Soyer et al. 2010, Development). At the molecular level, loss of Rfx6 causes upregulation of precursor markers (NEUROG3, SOX9) with increased apoptosis, and marked reduction of Ins1, Ins2, Gcg, Sst, and Ghr transcripts.
4. Beta-cell functional/maturation defect (postnatal maintenance role). RFX6 is not only developmentally required but also maintains the mature beta-cell functional identity in adult islets (Piccand et al., PLoS Genetics 2014, PMC4542305) and is required in adult human alpha cells for gene expression maintenance (Diabetes 2024). Mechanistically, RFX6 (via heterodimerization with RFX3, X-box promoter binding) directly activates the insulin gene and L-type calcium channel genes (CACNA1A, CACNA1C, CACNA1D) together with GPR68; loss of RFX6 abolishes glucose-stimulated Ca²⁺ influx and depolarization-evoked insulin exocytosis (Chandra et al., "RFX6 Regulates Insulin Secretion by Modulating Ca²⁺ Homeostasis in Human β Cells," Cell Reports 2014). Functional testing of patient missense alleles (R181W, V506G) confirmed failure of insulin-promoter transactivation "not significantly different from...an empty expression vector control," and failure to induce calcium-channel gene expression, despite retained nuclear localization (PMC9257252).
5. Enteroendocrine cell loss → protracted diarrhea (a distinct, recently elucidated arm). RFX6 is required for intestinal enteroendocrine cell (EEC) differentiation, promoting peptide-secreting EEC fates while repressing serotonin-producing enterochromaffin programs (biorxiv "Rfx6 promotes the differentiation of peptide-secreting enteroendocrine cells while repressing genetic programs controlling serotonin production"). In patients, this manifests as near-complete loss of GLP-1– and GIP-producing enteroendocrine cells: two patients studied by immunohistochemistry showed "nearly undetectable fasting and postprandial GLP-1 plasma levels" and "absence of GLP-1 immunostaining in distal intestine and rectum," with "considerable depletion of chromogranin A" (J Clin Endocrinol Metab 2021, DOI 10.1210/clinem/dgaa916). Because GLP-1 normally mediates the ileal-brake mechanism (inhibiting gastric emptying and slowing small-bowel motility), its congenital absence is proposed as a specific, previously unrecognized mechanism of the syndrome's severe protracted diarrhea — supported therapeutically by rapid clinical response to the GLP-1 analogue liraglutide in one patient (stool frequency fell from many episodes/day to 1–3/day within 6 days).
6. Exocrine pancreatic and hepatobiliary consequences. Exocrine acinar tissue is hypoplastic/dysfunctional (severe fecal elastase depression, poor/partial response to pancreatic enzyme replacement), and gallbladder/biliary tract agenesis or hypoplasia with cholestasis reflects RFX6's broader role across endoderm-derived digestive organ morphogenesis, not solely the endocrine pancreas.
7. Possible oncogenic/cancer-predisposition arm (emerging, single case-level evidence). A transcriptomic case study of heterotopic gastric mucosa in a Mitchell-Riley syndrome patient found RFX6 dysregulation among the most notable differentially expressed transcription factors also implicated in sporadic gastric cancer, raising a hypothesis (not yet confirmed at cohort level) that ectopic gastric mucosa in these patients carries elevated malignant-transformation risk (Orphanet J Rare Dis 2021, PMC8556982; broader review: "Multifaceted functions of transcription regulatory factor X6 (RFX6): from pancreatic development to cancer progression," Cancer Cell Int 2025).

Cell types involved: pancreatic endocrine progenitor cells; pancreatic alpha, beta, delta, epsilon islet cells (all NEUROG3-lineage-derived except PP cells); pancreatic acinar/exocrine cells; intestinal enteroendocrine cells (L-cells/GLP-1, K-cells/GIP); duodenal/gut-tube epithelial progenitors; gallbladder/biliary epithelium.

Suggested ontology terms: - GO (biological process): GO:0031018 (endocrine pancreas development), GO:0030154 (cell differentiation), GO:0030073 (insulin secretion), GO:0061668 (mitochondrial ribosome — n/a), GO:0007186 (relevant only if signaling detail added); more specifically GO:0021789 / islet development terms and GO:0035773 (insulin secretion involved in cellular response to glucose stimulus) - GO (molecular function): GO:0000981 (DNA-binding transcription factor activity, RNA Pol II-specific), GO:0043565 (sequence-specific DNA binding) - CL (cell type): CL:0000169 (type B pancreatic cell / beta cell), CL:0000171 (type A pancreatic cell / alpha cell), CL:0002563 (intestinal enteroendocrine cell), CL:0000160 (secretory cell) - UBERON: UBERON:0001264 (pancreas), UBERON:0001274 (pancreatic acinus), UBERON:0002114 (duodenum), UBERON:0002110 (gallbladder)

Sources: - Rfx6 directs islet formation and insulin production in mice and humans - PubMed - Rfx6 is an Ngn3-dependent winged helix transcription factor required for pancreatic islet cell development - PMC - RFX6 Regulates Insulin Secretion by Modulating Ca2+ Homeostasis in Human β Cells - ScienceDirect - Congenital Glucagon-like Peptide-1 Deficiency in the Pathogenesis of Protracted Diarrhea in Mitchell–Riley Syndrome - JCEM - Mitchell-Riley syndrome iPSCs exhibit reduced pancreatic endoderm differentiation due to a mutation in RFX6 - Development - Determining oncogenic patterns and cancer predisposition through the transcriptomic profile in Mitchell–Riley syndrome - PMC - Multifaceted functions of transcription regulatory factor X6 (RFX6): from pancreatic development to cancer progression - Cancer Cell International

7. Anatomical Structures Affected

Organ level: - Primary: pancreas (endocrine islets and exocrine acini — hypoplasia/annular pancreas), gallbladder and extrahepatic biliary tree (aplasia/hypoplasia, atresia), duodenum/proximal jejunum (atresia/stenosis, malrotation), stomach (heterotopic gastric mucosa in the intestine in some cases) - Secondary/complication-driven: liver (cholestasis, progressive failure requiring transplant in severe cases), bone marrow/hematologic system (anemia, coagulopathy secondary to malabsorption/vitamin K deficiency), overall growth (IUGR, failure to thrive) - Body systems involved: endocrine system (pancreatic islets), digestive system (pancreas, biliary tract, small intestine, stomach), hepatobiliary system, hematologic system, genitourinary system (hypospadias in a subset)

Tissue/cell level: pancreatic islet endocrine tissue (alpha/beta/delta/epsilon cells depleted; PP cells relatively spared); pancreatic exocrine acinar epithelium; intestinal enteroendocrine cells (L-cells, K-cells) diffusely depleted; duodenal/gut-tube epithelium (patterning defect); gallbladder/biliary epithelium; heterotopic gastric epithelium within the intestine in a subset.

Subcellular level: RFX6 itself is a nuclear transcription factor (GO Cellular Component: nucleus, GO:0005634); its downstream targets include plasma-membrane L-type calcium channels (CACNA1A/C/D) central to insulin-exocytosis machinery, and secretory-granule components of enteroendocrine/islet cells.

Localization: Bilateral/systemic — this is a developmental patterning disorder affecting midline/foregut-derived organs rather than a laterality or unilateral process; no organ-specific lateralization is reported.

Suggested UBERON terms: UBERON:0001264 (pancreas), UBERON:0001982 (islet of Langerhans), UBERON:0002114 (duodenum), UBERON:0002115 (jejunum), UBERON:0002110 (gallbladder), UBERON:0001173 (extrahepatic bile duct), UBERON:0002107 (liver), UBERON:0000945 (stomach — heterotopic mucosa).

Sources: As above (OMIM #615710; PMC9257252; PMC8556982).

8. Temporal Development

Onset: Congenital, with prenatal detectability in many cases — duodenal atresia and polyhydramnios are frequently identified on prenatal ultrasound; diabetes and severe diarrhea manifest in the immediate neonatal period (typically within the first days to weeks of life). This is a neonatal-onset disorder by definition (diabetes onset defines "neonatal diabetes mellitus" as onset before 6 months of age, per standard NDM diagnostic convention).

Onset pattern: Acute at birth for the structural anomalies (intestinal obstruction from atresia is a surgical neonatal emergency); the diabetes and diarrhea are of abrupt neonatal onset but then become a chronic, permanent condition.

Progression: - Diabetes: stable but lifelong/permanent — no remission is described (contrasts with transient neonatal diabetes mellitus subtypes seen with other genetic causes such as 6q24 imprinting defects). Glycemic control has historically been extremely difficult in infancy (high insulin sensitivity, exaggerated and prolonged hypoglycemic responses, glucagon-resistant hypoglycemia) but becomes more manageable with age and advanced insulin-delivery technology. - GI/nutritional disease: most severe in infancy, often improving (parenteral-nutrition weaning achievable) by early childhood in surviving patients, though intestinal failure can persist and drive transplant decisions. - Hepatobiliary disease: variable — ranges from self-limited mild cholestasis to progressive liver failure requiring transplantation within the first year of life. - Disease course pattern: chronic and multi-organ, not classically relapsing-remitting, though episodic exacerbations of diarrhea (e.g., triggered by enteral feeding attempts or intercurrent gastroenteritis) are described.

Remission patterns: No spontaneous remission of diabetes is reported. Partial "remission" of GI symptoms (successful parenteral-nutrition discontinuation, tolerance of oral diet) has been achieved in a subset of long-term survivors under intensive multidisciplinary management — most notably the oldest reported case (13.5 years old at last follow-up), who discontinued parenteral nutrition at age 1 and now tolerates a normal diet.

Critical periods: The first 6 months to 2 years of life represent the critical high-mortality/high-morbidity window (historical mortality concentrated in this period from sepsis and liver failure); intensive multidisciplinary neonatal/infant management is the key modifiable intervention window.

Sources: Mitchell–Riley Syndrome: Improving Clinical Outcomes - PMC; First multivisceral transplantation in Mitchell-Riley/Martinez-Frias syndrome - PubMed

9. Inheritance and Population

Epidemiology: Mitchell-Riley syndrome is classified by Orphanet as an ultra-rare disease (ORPHA:293864); no formal population-based prevalence or incidence estimate exists — the disease is known essentially only from ~16–20 published genetically-confirmed cases worldwide since its molecular characterization in 2010 (case-series/case-report literature only, no national registry data). This corresponds to Orphanet prevalence class "Not yet documented" and dismech prevalence_class: NOT_YET_DOCUMENTED would be the appropriate curated value, with measure_type: CASES_IN_LITERATURE.

Inheritance pattern: Autosomal recessive — confirmed in all reported families; consanguinity is common among reported probands (multiple kindreds with parental consanguinity, including third-degree relative unions). Recurrence risk for carrier (heterozygous) parents of an affected child is the standard 25% for autosomal recessive disease, with a 50% chance of each subsequent child being an unaffected carrier and 25% chance of being unaffected/non-carrier.

Penetrance: Biallelic null/null genotypes appear to be fully penetrant for the neonatal-diabetes component, though the severity and completeness of the extra-pancreatic malformation phenotype is variable (some reported cases atypically lack certain classic features, e.g., a case lacking facial dysmorphism, or presenting additional unreported features such as cerebral calcifications/coagulopathy in PMC5096485). In contrast, the allelic heterozygous MODY phenotype shows markedly reduced penetrance (~27% by age 25).

Expressivity: Variable — genotype-phenotype correlation is imperfect; missense/hypomorphic biallelic genotypes can present with a milder, later (childhood-onset) diabetes phenotype without the full visceral malformation syndrome, while null/null genotypes tend toward the classic severe multi-organ MRS phenotype.

Genetic anticipation: Not applicable/not reported — RFX6 pathogenic variants are not repeat-expansion mutations, and no anticipation phenomenon has been described.

Germline mosaicism: Not specifically reported in the literature reviewed.

Founder effects: The Finnish-enriched p.His293LeufsTer7 RFX6 allele (~1:250 carriers) represents a population-specific founder-type enrichment relevant primarily to the milder MODY/T2D-risk allelic spectrum rather than to classic biallelic Mitchell-Riley syndrome per se, but raises the theoretical possibility of elevated biallelic disease frequency in Finland.

Consanguinity role: Central — the overwhelming majority of reported MRS cases arise in consanguineous families, consistent with the disease's autosomal recessive, ultra-rare-allele genetics.

Carrier frequency: ~0.027–0.045% for RFX6 protein-truncating variants in non-Finnish European gnomAD/ExAC populations; ~0.4% (1:250) in the Finnish population for the specific enriched founder allele.

Population demographics: Reported cases span multiple ethnicities/geographies (UAE, European, and other consanguineous-practicing populations represented in the case-report literature); no single ethnic group is disproportionately affected by biallelic disease outside of the general elevated risk conferred by consanguinity practices. Sex ratio and age-distribution data are not separately tabulated given the extremely small published case count (case reports do not permit robust demographic inference).

Sources: - Entry - #615710 - MITCHELL-RILEY SYNDROME; MTCHRS - OMIM - RFX6 haploinsufficiency predisposes to diabetes through impaired beta cell function - PMC - Heterozygous RFX6 protein truncating variants are associated with MODY with reduced penetrance - Nature Communications

10. Diagnostics

Clinical/prenatal detection: Prenatal ultrasound frequently detects duodenal atresia (classic "double bubble" sign) and polyhydramnios, prompting antenatal suspicion. Postnatal presentation includes bilious vomiting/intestinal obstruction (from atresia/malrotation), neonatal hyperglycemia requiring insulin, and profuse watery diarrhea once enteral feeding is attempted.

Laboratory tests: - Blood glucose, HbA1c, and C-peptide (low/undetectable, confirming absolute insulin deficiency consistent with neonatal diabetes) - Fecal elastase-1 (severely depressed, confirming exocrine pancreatic insufficiency; reported values <50 µg/g in a documented case) - Coagulation studies (Factor VII, Factor IX; vitamin K levels) - Complete blood count (normocytic normochromic anemia) - Liver function tests / conjugated bilirubin (cholestasis) - Fasting/postprandial GLP-1 and GIP levels (research-level testing; found "nearly undetectable" in studied patients, supporting the enteroendocrine-deficiency mechanism)

Imaging: - Abdominal ultrasound/MRI/CT: pancreatic hypoplasia or annular pancreas, gallbladder aplasia/hypoplasia, biliary tract anomalies - Upper GI contrast series: duodenal/jejunal atresia, malrotation

Histopathology/biopsy: Intestinal/rectal biopsy with immunohistochemistry for chromogranin A, GLP-1, and GIP can confirm enteroendocrine cell depletion (used diagnostically/mechanistically in the JCEM 2021 report); pancreatic or ectopic gastric mucosal histology can identify heterotopic gastric tissue.

Genetic testing (definitive diagnosis): - Single-gene RFX6 sequencing is the primary confirmatory test, appropriate given the syndrome's specific, well-characterized monogenic cause - Neonatal diabetes gene panels (which routinely include RFX6 alongside INS, KCNJ11, ABCC8, GATA6, PTF1A, PDX1, EIF2AK3, and others) are the standard clinical approach when neonatal diabetes with syndromic GI features is suspected - Whole exome/genome sequencing is appropriate for atypical presentations or when panel testing is non-diagnostic, especially given the atypical/expanded phenotypes reported in some cases (e.g., the PMC5096485 case with unexpected coagulopathy and cerebral calcifications) - Homozygosity mapping/autozygosity analysis is useful in consanguineous families (used in the original Smith et al. 2010 gene-discovery study) - Chromosomal microarray/karyotype are not primary diagnostic tools here (no CNV/structural mechanism), but may be used to exclude differential diagnoses

Standardized diagnostic criteria: No formal consensus diagnostic-criteria document (e.g., no dedicated GeneReviews chapter was identified) exists specifically for Mitchell-Riley syndrome; diagnosis rests on the combination of neonatal diabetes + duodenal/jejunal atresia + pancreatic hypoplasia + gallbladder aplasia/hypoplasia, confirmed by biallelic RFX6 pathogenic variants.

Differential diagnosis: Other syndromic causes of neonatal diabetes with GI malformation should be considered and excluded, including: - GATA6-related pancreatic agenesis with congenital heart disease - PTF1A-related pancreatic and cerebellar agenesis - PDX1-related pancreatic agenesis - EIF2AK3 (Wolcott-Rallison syndrome) — neonatal diabetes with epiphyseal dysplasia - 6q24-related transient neonatal diabetes mellitus (imprinting defect) — distinguished by transient course - Isolated (non-syndromic) intestinal/duodenal atresia without diabetes - Martinez-Frias syndrome (now understood to be allelic/overlapping, not a true differential)

Screening: No population-based newborn screening applies specifically to this ultra-rare disease; carrier screening would only be relevant in known consanguineous families or populations with documented RFX6 founder alleles (e.g., targeted carrier testing could be considered in Finland given the founder-allele enrichment, though this is not a currently established screening program per the literature reviewed).

Sources: - A Newly-Discovered Mutation in the RFX6 Gene of the Rare Mitchell-Riley Syndrome - PMC - Congenital Glucagon-like Peptide-1 Deficiency in the Pathogenesis of Protracted Diarrhea in Mitchell–Riley Syndrome - JCEM - Rfx6 directs islet formation and insulin production in mice and humans - PubMed

11. Outcome/Prognosis

Historical mortality: Prognosis has historically been poor. In the largest cited series of homozygous cases prior to modern intensive management, 7 of 12 homozygous patients (~58%) died before age 6 months, predominantly from sepsis and liver failure. Early literature (the original 2010 gene-discovery report and subsequent early case reports) characterized the syndrome as generally lethal in infancy.

Improving outcomes with modern management: A 2022 case series of 4 patients managed with intensive multidisciplinary care (endocrinology, gastroenterology, hepatology, surgery) reported zero deaths, with patients surviving to ages 2.25–13.5 years at last follow-up, contrasting sharply with the historical cohort (PMID:35813646). This represents a substantial and clinically important shift in prognosis attributable to advances in neonatal intensive care, parenteral nutrition management, advanced diabetes technology (sensor-augmented insulin pumps with predictive low-glucose suspension), and transplant surgery — not to any disease-modifying pharmacologic therapy.

Multivisceral transplantation as a prognosis-altering intervention: The first reported multivisceral transplant (stomach, duodenum, small intestine, colon, liver, and pancreas) in Mitchell-Riley/Martinez-Frias syndrome, performed at age 2, resulted in more than 10 years of subsequent normal gastrointestinal, hepatic, and pancreatic graft function with no surgical complications — representing one of the longest reported survival periods for this syndrome and establishing multivisceral transplantation as a viable option in select severe cases (PMID:35307919).

Morbidity/complications: Even among survivors, chronic morbidity is substantial: parenteral-nutrition dependency (ranging widely, e.g., 58–119% PN-dependency index across the 2022 series), recurrent hypoglycemia, cholestatic liver disease (progressing to transplant need in a subset), coagulopathy, chronic anemia, growth impairment, and (in at least one case) concern for later malignant transformation of heterotopic gastric mucosa.

Quality of life measures: No standardized QoL instrument data identified.

Prognostic factors: Genotype severity (null/null vs. hypomorphic), degree of exocrine pancreatic and hepatobiliary involvement, presence/severity of cholestasis and coagulopathy, and — most importantly per the recent literature — access to intensive, coordinated multidisciplinary neonatal/pediatric management are the dominant prognostic determinants identified to date; no molecular prognostic biomarker beyond genotype has been established.

Sources: - Mitchell–Riley Syndrome: Improving Clinical Outcomes and Searching for Functional Impact of RFX-6 Mutations - PMC - First multivisceral transplantation in Mitchell-Riley/Martinez-Frias syndrome - PubMed

12. Treatment

Pharmacotherapy — diabetes management: - Insulin therapy is the mainstay: initial intravenous insulin in the acute neonatal period, transitioning to continuous subcutaneous insulin infusion (CSII) with predictive low-glucose suspension pump systems given the marked propensity for severe, glucagon-resistant hypoglycemia and dramatic basal-rate fluctuations (basal rates have been reported to increase >10-fold during parenteral nutrition administration). Flash/continuous glucose monitoring (CGM) is used for ongoing management; some patients transition to multiple daily injections (MDI) later in childhood. Achieved HbA1c values in well-managed patients range roughly 40–59 mmol/mol (5.8–7.6%). - NCIT suggestion: treatment_term NCIT:C15986 (Pharmacotherapy) with therapeutic_agent = insulin (CHEBI:145810 insulin, or specific insulin analogue CHEBI terms).

Emerging/experimental pharmacotherapy — GLP-1 analogue for diarrhea: - Liraglutide (off-label GLP-1 receptor agonist) produced a rapid and marked reduction in stool frequency (from multiple daily episodes to 1–3/day within 6 days) in one patient with documented congenital GLP-1 deficiency, representing the first mechanism-targeted pharmacologic intervention reported for MRS-associated diarrhea (J Clin Endocrinol Metab 2021). This remains anecdotal (single/few-patient experience) but is mechanistically well-grounded. - NCIT suggestion: treatment_term NCIT:C15986 (Pharmacotherapy); therapeutic_agent liraglutide (CHEBI:63566 or similar); therapeutic_modality SMALL_MOLECULE/PEPTIDE.

Pancreatic enzyme replacement therapy: Used for exocrine pancreatic insufficiency but reported as only "partially effective" or ineffective, with steatorrhea persisting despite treatment in the reported case series. - NCIT suggestion: NCIT:C1954 or relevant pancreatic-enzyme therapeutic term.

Nutritional/supportive management: - Total/partial parenteral nutrition (PN) is essentially universal in infancy, with careful, protocolized PN-weaning strategies central to modern improved outcomes; free amino-acid elemental enteral formulas have been trialed but diarrhea often persists, limiting enteral advancement. Cow's-milk-protein allergy has complicated feeding advancement in a subset of patients. - NCIT suggestion: NCIT:C15447 (Dietary Intervention); NCIT:C15747 (Supportive Care).

Surgical/procedural interventions: - Neonatal surgical repair of intestinal atresia/malrotation (duodenoduodenostomy or similar) is required urgently in essentially all cases. - Liver transplantation for progressive cholestatic liver failure (performed in at least one reported case, at 7 months of age). - Multivisceral transplantation (stomach, duodenum, small intestine, colon, liver, pancreas en bloc) has been performed successfully in at least one case with >10-year graft/patient survival, representing the most definitive surgical intervention reported to date for severe intestinal/pancreatic/hepatic failure. - Failed islet-cell transplantation was attempted post-liver-transplant in one patient without durable benefit. - NCIT suggestions: NCIT:C15329 (Surgical Procedure), NCIT:C15289 (Organ Transplantation).

Blood product/factor support: Vitamin K supplementation, packed red blood cell transfusions for anemia, and (in a subset) clotting-factor replacement for documented Factor VII/Factor IX deficiency.

Treatment algorithm/strategy: The literature converges on a multidisciplinary, intensive supportive-care algorithm (endocrinology + gastroenterology + hepatology + surgery + nutrition) as the single most impactful "treatment," given that no disease-modifying or curative pharmacologic therapy exists — management is fundamentally organ-replacement/organ-support-based (insulin replacing absent endogenous insulin; PN/enteral support and eventually transplantation replacing failed intestinal/hepatic/pancreatic function) plus an emerging mechanism-targeted adjunct (GLP-1 analogue for the diarrhea).

Experimental/clinical trials: No registered ClinicalTrials.gov interventional trials specific to Mitchell-Riley syndrome were identified in this search (consistent with its ultra-rare status); management data derive entirely from case reports/series.

Sources: - Mitchell–Riley Syndrome: Improving Clinical Outcomes and Searching for Functional Impact of RFX-6 Mutations - PMC - Congenital Glucagon-like Peptide-1 Deficiency in the Pathogenesis of Protracted Diarrhea in Mitchell–Riley Syndrome - JCEM - First multivisceral transplantation in Mitchell-Riley/Martinez-Frias syndrome - PubMed

13. Prevention

Primary prevention: Because this is a fully genetic, autosomal recessive disorder with no environmental causal contribution, primary population-level prevention is not applicable in the traditional public-health sense. The only effective "primary prevention" avenue is reproductive/genetic: - Genetic counseling for known carrier couples (particularly in consanguineous unions or in families with a previously affected child), explaining the 25% recurrence risk per pregnancy. - Preimplantation genetic testing (PGT-M) and prenatal diagnosis (chorionic villus sampling/amniocentesis with RFX6 sequencing) are appropriate options for at-risk couples once the familial pathogenic variants are known. - Carrier screening could theoretically be considered in populations with elevated RFX6 PTV carrier frequency (e.g., Finland, ~1:250) or in consanguineous-practicing communities, though no established population carrier-screening program specific to RFX6/Mitchell-Riley syndrome was identified in this search.

Secondary prevention (early detection): - Prenatal ultrasound surveillance enabling early detection of duodenal atresia/polyhydramnios allows for delivery planning at a tertiary center equipped for immediate neonatal surgical and diabetes management — this early detection, rather than altering disease occurrence, materially improves outcomes by enabling prompt postnatal intervention. - Once one affected child is identified in a family, targeted prenatal/preimplantation testing for the known familial variant(s) in subsequent pregnancies constitutes effective secondary-level risk management.

Tertiary prevention (preventing complications in affected individuals): This is where most of the "prevention" literature for MRS actually resides — preventing death and severe morbidity in already-affected infants via the intensive multidisciplinary management protocols described in Section 12 (careful glycemic control to prevent hypoglycemic/hyperglycemic complications, protocolized PN weaning to prevent PN-associated liver disease, vitamin K/coagulation monitoring to prevent bleeding complications, and early transplant referral to prevent end-stage organ failure).

Vaccination/immunization, behavioral interventions, public-health/environmental interventions, and prophylactic medications: Not applicable — no disease-specific programs exist given the purely monogenic recessive etiology.

Sources: Mitchell–Riley Syndrome: Improving Clinical Outcomes - PMC; general ACMG/genetic-counseling principles for autosomal recessive disease (no disease-specific guideline document identified).

14. Other Species / Natural Disease

Taxonomy of relevant model species: Mouse (Mus musculus, NCBITaxon:10090), zebrafish (Danio rerio, NCBITaxon:7955), and (per the winged-helix TF literature) Xenopus have all been used to study Rfx6 function; no naturally-occurring veterinary/companion-animal disease analogous to Mitchell-Riley syndrome has been reported (unlike many single-gene disorders that have recognized canine/feline natural-disease counterparts catalogued in OMIA).

Orthologous gene: Mouse Rfx6 — MGI:2445208 (NCBI Gene ortholog); zebrafish rfx6.

Natural disease in other species: No entry for RFX6-related disease was identified in OMIA (Online Mendelian Inheritance in Animals) in this search, indicating no recognized naturally-occurring veterinary correlate — Rfx6 pathology in non-human species has been studied exclusively through induced (knockout/morphant) models, not spontaneous natural disease.

Comparative pathology: The core RFX6-dependent developmental mechanism (NEUROG3-downstream direction of islet endocrine cell differentiation) is deeply evolutionarily conserved — required for islet cell development in mouse, zebrafish, and Xenopus alike, and zebrafish studies additionally reveal that pancreatic endocrine cells (PECs) and enteroendocrine cells (EECs) share substantial transcriptomic and regulatory-program overlap with mammalian systems, reinforcing translational relevance of non-mammalian models for the GI/enteroendocrine arm of the human disease.

Zoonotic potential/transmission: Not applicable — this is a non-infectious, purely genetic developmental disorder.

Sources: - Rfx6 directs islet formation and insulin production in mice and humans - PubMed - Pancreatic and intestinal endocrine cells in zebrafish share common transcriptomic signatures and regulatory programmes - BMC Biology - Rfx6 MGI Mouse Gene Detail - MGI:2445208

15. Model Organisms

Mouse models (primary in vivo model): - Constitutive Rfx6 knockout mice: Homozygous null mice recapitulate the core human phenotype closely — neonatal diabetes and intestinal obstruction with variable pancreatic hypoplasia, and homozygotes die shortly after birth. At the molecular level, loss of Rfx6 causes failure to generate all major islet endocrine cell types except pancreatic-polypeptide cells, with upregulation of precursor markers (NEUROG3, SOX9), increased apoptosis, and near-complete loss of Ins1, Ins2, Gcg, Sst, and Ghr transcripts (Smith et al. 2010, Nature, PMID:20148032; Soyer et al. 2010, Development, PMID:20040488). - Conditional/adult-inducible Rfx6 loss: Used to separately establish RFX6's postnatal maintenance role in mature beta cells (loss in adulthood causes progressive beta-cell dysfunction/dedifferentiation rather than only a developmental defect) — Piccand et al., PLoS Genetics 2014 ("Rfx6 Maintains the Functional Identity of Adult Pancreatic β Cells," PMC4542305). - Phenotype recapitulation: Strong — the mouse null phenotype (neonatal-lethal diabetes + intestinal obstruction + islet endocrine cell loss) closely mirrors human severe MRS, making mouse the most translationally faithful in vivo model. Limitation: mouse models show variable pancreatic hypoplasia severity and do not fully recapitulate the human gallbladder-aplasia component or the enteroendocrine/GLP-1-deficiency diarrhea mechanism as directly as human tissue/organoid studies have.

Zebrafish models: - Rfx6 is expressed in pancreatic endocrine progenitor and mature islet cells, analogous to mouse, and is required for proper islet cell development. - Zebrafish studies have been particularly informative for the shared regulatory program between pancreatic and intestinal (enteroendocrine) endocrine cells, relevant to understanding the GI/enteroendocrine arm of the human disease (BMC Biology 2020).

Human cellular/iPSC and organoid models (increasingly central to mechanistic understanding): - Patient-derived iPSCs carrying RFX6 loss-of-function mutations (e.g., c.1129C>T) reproduce a normal definitive-endoderm/gut-tube stage but a specific, quantifiable block at the PDX1+/SOX9+ pancreatic endoderm stage, directly modeling the human pancreatic hypoplasia mechanism at the cellular level (Development 2020). - CRISPR-engineered RFX6-null and RFX6-heterozygous stem-cell-derived islets (SC-islets): RFX6−/− SC-islets fail to generate insulin-secreting beta cells (mirroring MRS), while RFX6+/− SC-islets show haploinsufficiency (54% RFX6 protein reduction) with impaired beta-cell maturation, calcium signaling, and 54–62% reduced insulin secretion — directly modeling the heterozygous MODY phenotype as well (PMID:38743124). - Human intestinal organoids with RFX6 mutations: Demonstrate RFX6's essential, PDX1-upstream role in establishing/maintaining duodenal identity, directly modeling the intestinal-atresia/patterning arm of the human disease (bioRxiv/Development organoid studies).

Applications: These complementary models allow dissection of the distinct developmental (endoderm patterning, pancreatic specification), functional/maintenance (adult beta-cell identity, calcium-dependent insulin secretion), and enteroendocrine (GLP-1/GIP-producing cell) arms of RFX6 pathology — collectively explaining, mechanism by mechanism, each component of the human multi-organ phenotype (diabetes, pancreatic hypoplasia, intestinal atresia/patterning defect, and protracted diarrhea).

Resources: MGI (Rfx6, MGI:2445208) for mouse allele/phenotype data; ZFIN for zebrafish; no dedicated IMPC/KOMP full phenotyping pipeline entry was specifically surfaced in this search, though Rfx6 knockout alleles are catalogued in MGI.

Sources: - Rfx6 directs islet formation and insulin production in mice and humans - PMC - Rfx6 is an Ngn3-dependent winged helix transcription factor required for pancreatic islet cell development - PMC - Rfx6 Maintains the Functional Identity of Adult Pancreatic β Cells - PMC - Mitchell-Riley syndrome iPSCs exhibit reduced pancreatic endoderm differentiation due to a mutation in RFX6 - Development - RFX6 haploinsufficiency predisposes to diabetes through impaired beta cell function - PMC

Curation Notes for dismech (Important Caveats)

1. Verify all PMIDs and ontology-term IDs before KB entry. Several PMIDs above were resolved with high confidence directly from search-result URLs (e.g., 20148032, 26264437, 29026101, 38743124, 35307919, 20040488), but a few — notably the exact PMIDs for the JCEM GLP-1 paper (DOI 10.1210/clinem/dgaa916), the Development 2020 iPSC paper, the Orphanet J Rare Dis 2021 transcriptomic case report, and the Chandra et al. 2014 Cell Reports paper — were not independently confirmed in this pass and should be looked up on PubMed directly (just fetch-reference) before use. HPO term IDs marked "(verify)" above are best-effort suggestions, not OAK-validated.
2. This is squarely a create-module/RFX6 allelic-series curation candidate — the RFX6 biallelic-null (Mitchell-Riley) vs. biallelic-hypomorphic (childhood diabetes) vs. heterozygous-truncating (MODY) spectrum is a clean worked example for the schema's genotype/functional-impact-category modeling guidance, and the GLP-1/enteroendocrine-deficiency diarrhea mechanism is a strong, evidence-rich, mechanistically novel pathophysiology node distinct from the "generic malabsorption" framing used in older case reports.
3. Martinez-Frias syndrome (OMIM #601346) should likely be curated as the same disease entity or an explicitly cross-referenced allelic/overlapping entry, not independently, given the literature's convergence on "Mitchell-Riley/Martinez-Frias syndrome" as a combined designation — a design decision worth checking against docs/explanation/design-decisions.md before curation.

Sources: see inline citations throughout; primary aggregation points were OMIM #615710, OMIM *612659, PMC9257252, and PubMed 20148032.