Type I Diabetes

name: Type I Diabetes
creation_date: '2025-12-04T16:57:31Z'
updated_date: '2026-05-09T14:24:38Z'
category: Metabolic
parents:
- Autoimmune Disease
- Diabetes Mellitus
prevalence:
- population: Global
  percentage: 0.1-0.2
  evidence:
  - reference: PMID:34599655
    reference_title: "Type 1 diabetes in 2017: global estimates of incident and prevalent cases in children and adults."
    supports: REFUTE
    snippet: Global numbers of incident and prevalent cases of type 1 diabetes were estimated to be 234,710 and 9,004,610, respectively, in 2017...Globally, type 1 diabetes represents about 2% of the estimated total cases of diabetes.
    explanation: The prevalence of type 1 diabetes globally is estimated to be around 2%, not 0.1-0.2%.
  - reference: PMID:16085737
    reference_title: "Diabetes and ethnic minorities."
    supports: NO_EVIDENCE
    snippet: The global prevalence of diabetes for all age groups is estimated to be 2.8%. Type 2 diabetes accounts for at least 90% of diabetes worldwide.
    explanation: This study provides global prevalence data for diabetes in general and specifically mentions Type 2 diabetes but does not give a percentage for the prevalence of Type 1 diabetes.
  - reference: PMID:27959859
    reference_title: "Type 1 Diabetes Prevention: A Goal Dependent on Accepting a Diagnosis of an Asymptomatic Disease."
    supports: REFUTE
    snippet: The incidence of childhood-onset type 1 diabetes has been increasing at a rate of 3%-5% per year globally...no means for a practical 'cure' exist.
    explanation: The increasing incidence suggests a prevalence higher than 0.1-0.2%.
progression:
- phase: Onset
  age_range: Childhood-Adolescence
  evidence:
  - reference: PMID:33825933
    reference_title: "[Type 1 diabetes: an update]."
    supports: SUPPORT
    snippet: The incidence of type 1 diabetes (T1D) has been rising steadily over the last 30 years, especially among children and adolescents, with the result that the number of cases in this age group doubles every 20 years.
    explanation: This study discusses the rising incidence of type 1 diabetes in children and adolescents, which aligns with the progression of T1D during childhood and adolescence.
  - reference: PMID:30628751
    reference_title: "Predicting progression to type 1 diabetes from ages 3 to 6 in islet autoantibody positive TEDDY children."
    supports: PARTIAL
    snippet: Twenty-one percent of subjects developed T1D by age 6. Logistic regression modeling identified 5 significant predictors.
    explanation: This study focuses on predictors of T1D progression in children with high-risk HLA genes followed in The TEDDY study, providing partial support since it includes childhood but doesn't explicitly cover adolescence.
  - reference: PMID:20723813
    supports: NO_EVIDENCE
    snippet: ''
    explanation: This reference only provides a foreword and does not include specific information about the progression phase or onset of Type 1 Diabetes.
  - reference: PMID:26404926
    reference_title: "Staging presymptomatic type 1 diabetes: a scientific statement of JDRF, the Endocrine Society, and the American Diabetes Association."
    supports: SUPPORT
    snippet: Stage 3 as onset of symptomatic disease ... Adoption of this staging classification provides a standardized taxonomy for type 1 diabetes.
    explanation: This reference discusses the presymptomatic stages of T1D leading to symptomatic onset, supporting the progression during childhood and adolescence.
  - reference: PMID:31280235
    reference_title: "Children with type 1 diabetes of early age at onset - immune and metabolic phenotypes."
    supports: PARTIAL
    snippet: We aimed to evaluate children with type 1 diabetes (T1D) with early age at onset (EAO) for clinical, immune and metabolic features in order to identify age-related disease phenotypes.
    explanation: This study focuses on early age at onset and disease phenotypes in children, but doesn't explicitly cover the entire range including adolescence.
  - reference: PMID:33274481
    supports: NO_EVIDENCE
    snippet: ''
    explanation: The reference title suggests outcomes over a 20-year period but doesn't provide specific data on the progression phase or onset of Type 1 Diabetes during childhood and adolescence in the provided abstract.
  - reference: PMID:26816135
    reference_title: "Childhood and Youth Onset Diabetes: A Single Centre Experience."
    supports: SUPPORT
    snippet: Type 1 diabetes accounted for 368/421 (87.4 %) patients with age of onset <18 y and 99/156 (63.5 %) of patients with onset between 19 and 25 y of age.
    explanation: This study identifies the proportion of various types of diabetes in youth, including the onset of T1D in children and adolescents.
pathophysiology:
- name: Genetic Susceptibility
  description: Certain HLA gene variants (HLA-DQ2, HLA-DQ8) and other susceptibility genes (INS) increase the risk of developing Type I Diabetes.
  genes:
  - preferred_term: HLA-DQ2
  - preferred_term: HLA-DQ8
  - preferred_term: INS
    term:
      id: hgnc:6081
      label: INS
  downstream:
  - target: Autoimmune Destruction of Beta Cells
  evidence:
  - reference: PMID:11554771
    reference_title: "Genetics of type 1 diabetes."
    supports: SUPPORT
    snippet: The HLA-DQ genes are the primary susceptibility genes within this region, although other genes may also contribute. The IDDM2 locus maps to a variable number of tandem repeats in the insulin gene region on chromosome 11.
    explanation: The provided literature confirms that HLA-DQ and INS genes contribute to the genetic susceptibility to Type 1 Diabetes.
  - reference: PMID:31331105
    reference_title: "HLA-DQA1 and HLA-DQB1 Alleles, Conferring Susceptibility to Celiac Disease and Type 1 Diabetes, are More Expressed Than Non-Predisposing Alleles and are Coordinately Regulated."
    supports: SUPPORT
    snippet: HLA DQA1*05 and DQB1*02 alleles encoding the DQ2.5 molecule and HLA DQA1*03 and DQB1*03 alleles encoding DQ8 molecules are strongly associated with celiac disease (CD) and type 1 diabetes (T1D), two common autoimmune diseases (AD)
    explanation: The presence of HLA-DQ2 and HLA-DQ8 variants contributing to the genetic susceptibility of Type I Diabetes is supported.
  - reference: PMID:3309680
    reference_title: "HLA-DQ beta gene contributes to susceptibility and resistance to insulin-dependent diabetes mellitus."
    supports: SUPPORT
    snippet: Over half of the inherited predisposition to insulin-dependent diabetes mellitus maps to the region of chromosome 6 that contains the highly polymorphic HLA class II genes which determine immune responsiveness.
    explanation: HLA class II genes, including HLA-DQ, play significant roles in the predisposition to Type I Diabetes.
  - reference: PMID:15342014
    reference_title: "The genetics of HLA-associated disease."
    supports: SUPPORT
    snippet: Accumulating evidence suggests that MHC susceptibility for T1D is recessive, with susceptibility alleles more common than protective alleles.
    explanation: The literature indicates that HLA alleles, specifically susceptibility alleles, are significant in the context of Type I Diabetes.
  - reference: PMID:17130534
    reference_title: "Genes influencing innate and acquired immunity in type 1 diabetes and latent autoimmune diabetes in adults."
    supports: SUPPORT
    snippet: DQ8 and DQ2 are associated with susceptibility to and DQ6 with protection from type 1 diabetes mellitus (T1DM).
    explanation: The association of HLA-DQ2 and HLA-DQ8 with susceptibility to Type I Diabetes is supported by this reference.
  - reference: PMID:17496359
    reference_title: "Biomarkers of susceptibility to type 1 diabetes with special reference to the Indian population."
    supports: SUPPORT
    snippet: Susceptibility to T1D is strongly linked to a major genetic locus that is the major histocompatibility complex (MHC) and several other minor loci including insulin, CTLA4 that contribute to diabetes risk in an epistatic way.
    explanation: INS gene contribution to the susceptibility of Type I Diabetes is supported along with HLA genes.
- name: Environmental Triggers
  description: Viral infections or early dietary factors (cow's milk, gluten) may trigger the autoimmune response in genetically susceptible individuals.
  triggers:
  - preferred_term: Viral Infections
  - preferred_term: Early Dietary Factors
  downstream:
  - target: Autoimmune Destruction of Beta Cells
  evidence:
  - reference: PMID:10522815
    reference_title: "Environmental factors in the pathogenesis of type 1 diabetes mellitus."
    supports: SUPPORT
    snippet: Various exogenous triggers, such as certain dietary factors and viruses, are thought to induce the autoimmune process leading in some individuals to extensive beta-cell destruction and ultimately to the clinical manifestation of type 1 diabetes.
    explanation: This reference supports the statement by mentioning that dietary factors and viruses can trigger the autoimmune process in genetically susceptible individuals.
  - reference: PMID:21162649
    reference_title: "Protection against or triggering of Type 1 diabetes? Different roles for viral infections."
    supports: SUPPORT
    snippet: The ability to induce strong cellular immune responses and to cause inflammation in the target organ makes viral infections prime candidates for the initiation of islet autoreactivity.
    explanation: The reference supports the role of viral infections in triggering autoimmune responses leading to type 1 diabetes.
  - reference: PMID:18357774
    reference_title: "The CVB and etiology of type 1 diabetes."
    supports: SUPPORT
    snippet: The most often cited environmental agents implicated as initiators of T1D are the human enteroviruses, in particular the group B coxsackieviruses (CVB).
    explanation: This reference supports the statement by identifying enteroviruses as environmental triggers for type 1 diabetes.
  - reference: PMID:9645989
    reference_title: "The pathogenesis of viral-induced diabetes."
    supports: SUPPORT
    snippet: dmsee@uci.edu Serologic case-control studies have suggested an association between coxsasckie group B viruses and insulin-dependent diabetes mellitus (IDDM)
    explanation: This reference supports the role of viral infections in the onset of type 1 diabetes.
  - reference: PMID:31593953
    reference_title: "Type 1 Diabetes Mellitus and Celiac Disease: Distinct Autoimmune Disorders That Share Common Pathogenic Mechanisms."
    supports: SUPPORT
    snippet: Viral infections and early exposure to gluten or cow''s milk in the infant diet have been implicated in disease pathogenesis.
    explanation: The reference supports the statement by linking viral infections and early dietary factors to the pathogenesis of type 1 diabetes.
- name: Interferon-Driven Beta Cell Response
  description: Type I and type II interferons upregulate antigen presentation and chemokine production in beta cells while downregulating oxidative phosphorylation, increasing immunogenicity and metabolic stress.
  cell_types:
  - preferred_term: type B pancreatic cell
    term:
      id: CL:0000169
      label: type B pancreatic cell
  biological_processes:
  - preferred_term: type I interferon signaling pathway
    term:
      id: GO:0060337
      label: type I interferon-mediated signaling pathway
  - preferred_term: antigen processing and presentation of peptide antigen via MHC class I
    term:
      id: GO:0002474
      label: antigen processing and presentation of peptide antigen via MHC class I
  - preferred_term: chemokine production
    term:
      id: GO:0032602
      label: chemokine production
  - preferred_term: oxidative phosphorylation
    term:
      id: GO:0006119
      label: oxidative phosphorylation
    modifier: DECREASED
  chemical_entities:
  - preferred_term: interferon-alpha
    description: Type I interferon that drives antiviral and antigen-presentation programs
  - preferred_term: interferon-gamma
    description: Type II interferon that induces HLA class I upregulation and chemokine production
  - preferred_term: C-X-C motif chemokine 10
    description: Chemokine (CXCL10) that recruits autoreactive T cells to islets
  downstream:
  - target: Autoimmune Destruction of Beta Cells
  evidence:
  - reference: PMID:38409439
    reference_title: "Interferons are key cytokines acting on pancreatic islets in type 1 diabetes."
    supports: SUPPORT
    snippet: IFN-α and IFN-γ had a greater impact on the beta cell transcriptome when compared with IL-1β and TNF-α. The IFN-induced gene signatures have a strong correlation with those observed in beta cells from individuals with type 1 diabetes.
    explanation: This study identifies interferons as key drivers of beta cell inflammatory responses, upregulating antigen presentation and chemokine production.
- name: Autoimmune Destruction of Beta Cells
  description: The immune system mistakenly targets and destroys insulin-producing beta cells in the pancreas through T cell-mediated cytotoxicity and autoantibody production.
  cell_types:
  - preferred_term: type B pancreatic cell
    term:
      id: CL:0000169
      label: type B pancreatic cell
  - preferred_term: CD8-positive, alpha-beta cytotoxic T cell
    term:
      id: CL:0000794
      label: CD8-positive, alpha-beta cytotoxic T cell
  - preferred_term: CD4-positive, alpha-beta T cell
    term:
      id: CL:0000624
      label: CD4-positive, alpha-beta T cell
  - preferred_term: regulatory T cell
    term:
      id: CL:0000815
      label: regulatory T cell
  - preferred_term: B cell
    term:
      id: CL:0000236
      label: B cell
  - preferred_term: dendritic cell
    term:
      id: CL:0000451
      label: dendritic cell
  - preferred_term: macrophage
    term:
      id: CL:0000235
      label: macrophage
  biological_processes:
  - preferred_term: T cell mediated cytotoxicity
    term:
      id: GO:0001913
      label: T cell mediated cytotoxicity
  - preferred_term: autoantibody production
    modifier: ABNORMAL
  - preferred_term: cytokine-mediated signaling pathway
    term:
      id: GO:0019221
      label: cytokine-mediated signaling pathway
  locations:
  - preferred_term: pancreatic islet
    term:
      id: UBERON:0000006
      label: islet of Langerhans
  downstream:
  - target: Insulin Deficiency
    description: Autoimmune destruction of pancreatic beta cells leads to absolute or near-absolute insulin deficiency.
    evidence:
    - reference: PMID:40734585
      reference_title: "The pathophysiology, presentation and classification of Type 1 diabetes."
      supports: SUPPORT
      snippet: Type 1 diabetes is characterised by the autoimmune destruction of pancreatic β‐cells, leading to an absolute or near‐absolute insulin deficiency.
      explanation: This 2025 review clearly establishes the causal chain from autoimmune destruction of beta cells to absolute insulin deficiency that characterizes Type 1 Diabetes.
  evidence:
  - reference: PMID:12185667
    reference_title: "Islet abnormalities in the pathogenesis of autoimmune diabetes."
    supports: PARTIAL
    snippet: Type 1 diabetes mellitus is a T-cell-mediated autoimmune disease that results in the destruction of the insulin-producing beta cells in the pancreatic islets of Langerhans.
    explanation: While T-cell mediated cytotoxicity is mentioned, there is no reference to autoantibody production.
  - reference: PMID:23774118
    reference_title: "Pathophysiological mechanisms involving aggressive islet cell destruction in fulminant type 1 diabetes."
    supports: PARTIAL
    snippet: Phenotypes of infiltrating cells around and/or into islets were mainly dendritic cells, macrophages and CD8+ T cells.
    explanation: Supports T cell-mediated cytotoxicity but does not discuss autoantibody production.
  - reference: PMID:27659143
    reference_title: "Immune and Pancreatic β Cell Interactions in Type 1 Diabetes."
    supports: PARTIAL
    snippet: The autoimmune destruction of the pancreatic islet beta cells is due to a targeted lymphocyte attack.
    explanation: Supports T cell-mediated cytotoxicity but does not mention autoantibody production.
  - reference: PMID:27017348
    reference_title: "Life and death of β cells in Type 1 diabetes: A comprehensive review."
    supports: PARTIAL
    snippet: Type 1 diabetes (T1D) is an autoimmune disorder characterized by the destruction of insulin-producing pancreatic beta cells.
    explanation: Describes immune-mediated destruction of beta cells but does not specifically mention autoantibody production.
  - reference: PMID:16280652
    reference_title: "Autoimmune destruction of pancreatic beta cells."
    supports: PARTIAL
    snippet: Type 1 diabetes results from the destruction of insulin-producing pancreatic beta cells by a beta cell-specific autoimmune process.
    explanation: Supports T cell-mediated cytotoxicity but does not address autoantibody production.
  - reference: PMID:34691077
    reference_title: "Partners in Crime: Beta-Cells and Autoimmune Responses Complicit in Type 1 Diabetes Pathogenesis."
    supports: PARTIAL
    snippet: Type 1 diabetes (T1D) is an autoimmune disease characterized by autoreactive T cell-mediated destruction of insulin-producing pancreatic beta-cells.
    explanation: Supports T cell-mediated cytotoxicity but lacks information on autoantibody production.
  - reference: PMID:33479911
    reference_title: "Regulatory B Cells in Type 1 Diabetes."
    supports: PARTIAL
    snippet: Type 1 diabetes is an organ-specific autoimmune disease characterized by immune-mediated beta cell destruction in pancreatic islets.
    explanation: Describes immune-mediated destruction but not autoantibody production.
  - reference: PMID:28625830
    reference_title: "Bioengineering strategies for inducing tolerance in autoimmune diabetes."
    supports: PARTIAL
    snippet: Type 1 diabetes is an autoimmune disease marked by the destruction of insulin-producing beta cells in the pancreatic islets.
    explanation: Indicates immune destruction of beta cells but does not mention autoantibody production.
- name: Insulin Deficiency
  description: Loss of beta cells leads to a deficiency of insulin, a hormone required for glucose uptake.
  downstream:
  - target: Hyperglycemia
  - target: Impaired Glucose Utilization
  - target: Increased Lipolysis
  evidence:
  - reference: PMID:35254878
    reference_title: "Type 1 Diabetes Mellitus."
    supports: SUPPORT
    snippet: Type 1 diabetes mellitus (T1DM) is an endocrine disorder in which pancreatic beta cells stop producing insulin, typically due to autoimmune destruction.
    explanation: This confirms that the loss of beta cells leads to a deficiency of insulin in Type 1 diabetes, as stated in the provided statement.
  - reference: PMID:21281836
    reference_title: "Pathophysiology of prediabetes."
    supports: NO_EVIDENCE
    snippet: Insulin resistance and defective glucose sensing at the beta-cell are the central pathophysiologic determinants that together cause hyperglycemia.
    explanation: Although it primarily discusses prediabetes and Type 2 diabetes, the excerpt supports the idea that beta-cell issues lead to hyperglycemia.
  - reference: PMID:2006409
    reference_title: "Diabetic hyperglycemia: link to impaired glucose transport in pancreatic beta cells."
    supports: PARTIAL
    snippet: Glucose uptake into pancreatic beta cells by means of the glucose transporter GLUT-2, which has a high Michaelis constant, is essential for the normal insulin secretory response to hyperglycemia.
    explanation: This indicates the importance of beta cells in glucose regulation and the resulting hyperglycemia when their function is impaired.
  - reference: PMID:11822099
    reference_title: "[Hepatogenic diabetes]."
    supports: NO_EVIDENCE
    snippet: Peripheral insulin-resistance and impairment of the hepatocellular function are two major possible causes of diabetes mellitus in liver cirrhosis.
    explanation: This reference is more about liver cirrhosis but supports the general mechanism where insulin deficiency, due to impaired beta-cell function, leads to diabetes.
  - reference: PMID:11508279
    reference_title: "The accelerator hypothesis: weight gain as the missing link between Type I and Type II diabetes."
    supports: PARTIAL
    snippet: Loss of blood glucose control might result from failure of the beta cells to secrete insulin, resistance of the tissues to its action, or a combination of both.
    explanation: This also supports the idea that loss of beta cells leads to insulin deficiency and subsequent glucose control issues, relevant to both Type 1 and Type 2 diabetes.
- name: Hyperglycemia
  description: Lack of insulin results in high blood glucose levels, as glucose cannot be efficiently taken up by cells.
  assays:
  - preferred_term: Elevated Blood Glucose
  - preferred_term: Elevated Hemoglobin A1c (HbA1c)
  downstream:
  - target: Glucosuria
  - target: Polyuria
  - target: Polydipsia
  - target: Diabetic Ketoacidosis (DKA)
  evidence:
  - reference: PMID:33970586
    reference_title: "Diabetes: Type 1 Diabetes."
    supports: SUPPORT
    snippet: Type 1 diabetes is defined as a state of hyperglycemia due to insulin deficiency caused by autoimmune pancreatic beta-cell destruction.
    explanation: The abstract from PMID:33970586 confirms that type 1 diabetes is characterized by hyperglycemia due to insulin deficiency, which supports the statement regarding elevated blood glucose and related downstream effects.
  - reference: PMID:37921158
    reference_title: "Multi-level Analysis of HbA1c in Diagnosis and Prognosis of Diabetic Patients."
    supports: PARTIAL
    snippet: HbA1c offers a trustworthy indicator of chronic hyperglycemia and strongly correlates with the likelihood of long-term consequences from diabetes.
    explanation: Although this reference supports the relationship between elevated HbA1c and hyperglycemia, it does not specifically address all the downstream effects such as Glucosuria, Polyuria, Polydipsia, and Diabetic Ketoacidosis (DKA).
  - reference: PMID:21281836
    reference_title: "Pathophysiology of prediabetes."
    supports: NO_EVIDENCE
    snippet: The phenotype of prediabetes includes dyslipidemia and higher arterial blood pressure.
    explanation: This study does not specifically address the pathophysiology of type 1 diabetes or the particular assays and downstream effects mentioned in the statement.
  - reference: PMID:11921414
    reference_title: "The insulin gene in diabetes."
    supports: NO_EVIDENCE
    snippet: Lack of insulin production or abnormalities affecting insulin secretion are key to the development of almost all forms of diabetes.
    explanation: While it mentions insulin deficiency, this reference does not go into detail about the specific assays and downstream effects listed in the statement.
  - reference: PMID:15137354
    reference_title: "Pathophysiology of diabetes mellitus."
    supports: NO_EVIDENCE
    snippet: The article points out the signs and symptoms to be aware of when the person is in the acute state of diabetic ketoacidosis.
    explanation: This article touches on diabetic ketoacidosis but does not fully cover all the listed downstream effects and assays associated with type 1 diabetes pathophysiology.
- name: Impaired Glucose Utilization
  description: Without insulin, cells are unable to utilize glucose for energy production, leading to cellular energy deficiency.
  downstream:
  - target: Weight Loss
  - target: Fatigue
  evidence:
  - reference: PMID:12477252
    reference_title: "Challenges for gene therapy of type 1 diabetes."
    supports: SUPPORT
    snippet: Type 1 or insulin-dependent diabetes mellitus is caused by autoimmune attack and selective destruction of the pancreatic beta cells.
    explanation: The lack of insulin in type 1 diabetes mellitus leads to impaired glucose utilization as described in the statement.
  - reference: PMID:15137354
    reference_title: "Pathophysiology of diabetes mellitus."
    supports: PARTIAL
    snippet: The following article reviews the basic pathophysiology of both type 1 diabetes mellitus and type 2 diabetes mellitus as we understand it today.
    explanation: This article explains that in diabetes, particularly type 1, the lack of insulin results in impaired glucose utilization, leading to characteristic symptoms like weight loss and fatigue.
- name: ER Stress and Unfolded Protein Response
  description: Inflammatory cytokines induce endoplasmic reticulum stress in beta cells, activating the unfolded protein response and contributing to beta cell dysfunction and apoptosis.
  cell_types:
  - preferred_term: type B pancreatic cell
    term:
      id: CL:0000169
      label: type B pancreatic cell
  biological_processes:
  - preferred_term: endoplasmic reticulum unfolded protein response
    term:
      id: GO:0030968
      label: endoplasmic reticulum unfolded protein response
  - preferred_term: apoptotic process
    term:
      id: GO:0006915
      label: apoptotic process
  chemical_entities:
  - preferred_term: interleukin-1beta
    description: Proinflammatory cytokine that contributes to beta-cell stress and ER dysfunction
  downstream:
  - target: Autoimmune Destruction of Beta Cells
  evidence:
  - reference: PMID:38409439
    reference_title: "Interferons are key cytokines acting on pancreatic islets in type 1 diabetes."
    supports: SUPPORT
    snippet: IFN-α and IFN-γ had a greater impact on the beta cell transcriptome when compared with IL-1β and TNF-α. The IFN-induced gene signatures have a strong correlation with those observed in beta cells from individuals with type 1 diabetes.
    explanation: This study shows interferons drive beta cell stress responses including ER stress pathways that contribute to beta cell dysfunction and death.
- name: Increased Lipolysis
  description: Insulin deficiency also leads to increased breakdown of fat (lipolysis) for energy, resulting in the production of ketones.
  downstream:
  - target: Diabetic Ketoacidosis (DKA)
  evidence:
  - reference: PMID:6409465
    reference_title: "Glucose and ketone body kinetics in diabetic ketoacidosis."
    supports: SUPPORT
    snippet: Insulin deficiency results in increased rates of lipolysis and provides increased substrate (free fatty acids) for ketogenesis.
    explanation: The article explains that insulin deficiency leads to increased lipolysis, which eventually results in the production of ketone bodies. This supports the statement's claim about the pathophysiology involving lipolysis and ketone production in Type I Diabetes.
  - reference: PMID:15137354
    reference_title: "Pathophysiology of diabetes mellitus."
    supports: SUPPORT
    snippet: The article points out the signs and symptoms to be aware of when the person is in the acute state of diabetic ketoacidosis.
    explanation: The article suggests that DKA is a critical concern in Type I Diabetes due to insufficient insulin, which is aligned with the statement indicating the downstream effect of heightened lipolysis and ketone production.
  - reference: PMID:34922394
    reference_title: "Clinical Significance of Insulin Peptide-specific Interferon-γ-related Immune Responses in Ketosis-prone Type 2 Diabetes."
    supports: PARTIAL
    snippet: the involvement of B:9-23rPep-specific IFN-gamma-related immunoreactivity in the pathophysiology of some unprovoked A-beta+ KPD.
    explanation: Although the study highlights immune responses related to ketosis-prone Type 2 Diabetes, it indirectly supports the notion that immune-mediated processes can contribute to ketosis and DKA.
- name: Chronic Complications
  description: Persistent hyperglycemia over time can lead to damage in various tissues and organs.
  downstream:
  - target: Retinopathy
  - target: Neuropathy
  - target: Nephropathy
  - target: Cardiovascular Disease
  evidence:
  - reference: PMID:31346658
    reference_title: "New insights into the mechanisms of diabetic complications: role of lipids and lipid metabolism."
    supports: SUPPORT
    snippet: Hyperglycaemia, dyslipidaemia and hypertension combine with the duration and type of diabetes to define the distinct pathophysiology underlying diabetic kidney disease, diabetic retinopathy and diabetic neuropathy.
    explanation: The literature indicates that hyperglycemia is a significant factor in the pathophysiology of diabetic complications including kidney disease (nephropathy), retinopathy, and neuropathy, thereby supporting the claim.
  - reference: PMID:34407376
    reference_title: "Type 1 Diabetes and Associated Cardiovascular Damage: Contribution of Extracellular Vesicles in Tissue Crosstalk."
    supports: SUPPORT
    snippet: Hyperglycemia is the common denominator for most of the chronic diabetic vascular complications, which represent the main cause of life reduction in T1D patients.
    explanation: This reference indicates that hyperglycemia underlies various chronic vascular complications in type 1 diabetes, thus supporting the statement.
  - reference: PMID:3528691
    reference_title: "Insulin-dependent diabetes mellitus: pathophysiology."
    supports: SUPPORT
    snippet: The remaining 15 to 20% of patients have insulin-dependent diabetes mellitus, a disorder caused by the destruction of insulin-producing endocrine cells within the pancreas and currently considered to be the result of an autoimmune process. During the course of both types of diabetes mellitus, the so-called long-term complications of diabetes invariably occur to some extent in all patients. These complications include retinopathy, nephropathy, neuropathy, and premature atherosclerosis.
    explanation: The study confirms that type 1 diabetes, which involves insulin-dependent diabetes mellitus, results in long-term complications such as retinopathy, nephropathy, neuropathy, and cardiovascular disease.
  - reference: PMID:35456511
    reference_title: "The Role of Epigenetic Modifications in Late Complications in Type 1 Diabetes."
    supports: SUPPORT
    snippet: The prevention of hyperglycemia is very important to avoid or at least postpone the development of micro- and macrovascular complications, also known as late complications. These include diabetic retinopathy, chronic renal failure, diabetic neuropathy, and cardiovascular diseases.
    explanation: The literature points out that hyperglycemia leads to microvascular (retinopathy, nephropathy, neuropathy) and macrovascular (cardiovascular diseases) complications, supporting the statement.
- name: Diabetic Ketoacidosis (DKA)
  description: Life-threatening metabolic emergency from insulin deficiency
phenotypes:
- category: Endocrine
  name: Hyperglycemia
  frequency: VERY_FREQUENT
  diagnostic: true
  sequelae:
  - target: Diabetic Ketoacidosis
  evidence:
  - reference: PMID:38272591
    reference_title: "Acute and Chronic Adverse Outcomes of Type 1 Diabetes."
    supports: PARTIAL
    snippet: Type 1 diabetes is associated with both acute and chronic complications. Acute complications include diabetic ketoacidosis and severe hypoglycemia. Chronic complications can be microvascular or macrovascular. Microvascular complications include retinopathy, nephropathy, and neuropathy.
    explanation: This source supports the statement by associating Type I Diabetes with hyperglycemia and chronic complications such as retinopathy and neuropathy, as well as acute complications like diabetic ketoacidosis.
  - reference: PMID:28544185
    reference_title: "Ketoacidosis at diagnosis of type 1 diabetes: Effect of prospective studies with newborn genetic screening and follow up of risk children."
    supports: PARTIAL
    snippet: Participation in prospective follow-up studies reduces the frequency of DKA in children at diagnosis of T1D, but genetic screening alone does not decrease DKA risk.
    explanation: This source supports the statement by confirming that Diabetic Ketoacidosis (DKA) is a frequent acute complication in Type 1 Diabetes at the time of diagnosis.
  - reference: PMID:34362315
    reference_title: "Stress hyperglycemia as first sign of asymptomatic type 1 diabetes: an instructive case."
    supports: SUPPORT
    snippet: Although SH was usually benign and long-term treatment was superfluous, it might be the first sign of insulinopenic status such as type 1 DM (T1DM)
    explanation: This source supports the statement by describing stress hyperglycemia as a potential initial presentation of Type 1 Diabetes, thereby confirming hyperglycemia as a very frequent occurrence.
  phenotype_term:
    preferred_term: Hyperglycemia
    term:
      id: HP:0003074
      label: Hyperglycemia
- category: Systemic
  name: Weight Loss
  frequency: FREQUENT
  notes: Due to inability to utilize glucose for energy
  evidence:
  - reference: PMID:23075321
    reference_title: "The broad clinical phenotype of Type 1 diabetes at presentation."
    supports: PARTIAL
    snippet: Immune-mediated (auto-immune) Type 1 diabetes mellitus is not a homogenous entity, but nonetheless has distinctive characteristics. In children, it may present with classical insulin deficiency and ketoacidosis at disease onset, whereas autoimmune diabetes in adults may not always be insulin dependent.
    explanation: The source does indicate that Type 1 diabetes has varied presentations, including insulin deficiency and potentially weight loss due to failure to utilize glucose. However, the excerpt does not specifically mention weight loss as a frequent phenotype.
  - reference: PMID:12949265
    supports: NO_EVIDENCE
    explanation: The provided literature does not directly discuss weight loss as a frequent systemic phenotype of Type 1 diabetes.
  - reference: PMID:11508279
    reference_title: "The accelerator hypothesis: weight gain as the missing link between Type I and Type II diabetes."
    supports: NO_EVIDENCE
    explanation: This reference discusses the Accelerator Hypothesis and weight gain in diabetes but does not address weight loss in Type 1 diabetes.
  - reference: PMID:37065759
    reference_title: "Can type 1 diabetes be an unexpected complication of obesity?"
    supports: PARTIAL
    snippet: The risk factors of weight gain included using exogenous insulin, intensifying insulin therapy, fear of hypoglycemia and related decrease in physical activity, and psychological factors, such as emotional eating and binge eating
    explanation: This reference addresses weight gain in relation to Type 1 Diabetes but does not state that weight loss is a frequent phenotype.
  - reference: PMID:19267337
    supports: NO_EVIDENCE
    explanation: The reference discusses the natural history of endogenous beta-cell function in Type 1 diabetes but does not mention weight loss being a frequent phenotype.
  phenotype_term:
    preferred_term: Weight loss
    term:
      id: HP:0001824
      label: Weight loss
- category: Systemic
  frequency: FREQUENT
  name: Polyuria
  notes: Caused by osmotic diuresis from hyperglycemia
  evidence:
  - reference: PMID:35254878
    reference_title: "Type 1 Diabetes Mellitus."
    supports: SUPPORT
    snippet: Symptoms include polyuria, polydipsia, and weight loss.
    explanation: This reference confirms that polyuria is a frequent symptom of Type I Diabetes.
  - reference: PMID:2923250
    reference_title: "Effect of blood glucose concentration on osmoregulation in diabetes mellitus."
    supports: SUPPORT
    snippet: Poorly controlled insulin-dependent diabetes mellitus is associated with considerable elevations of plasma vasopressin concentrations, although well-controlled diabetics have normal osmoregulated thirst and vasopressin release.
    explanation: This reference discusses the association of poorly controlled insulin-dependent diabetes mellitus (Type I Diabetes) with symptoms such as polyuria.
  phenotype_term:
    preferred_term: Polyuria
    term:
      id: HP:0000103
      label: Polyuria
- category: Systemic
  frequency: FREQUENT
  name: Polydipsia
  notes: Excessive thirst due to dehydration from polyuria
  evidence:
  - reference: PMID:35254878
    reference_title: "Type 1 Diabetes Mellitus."
    supports: SUPPORT
    snippet: Symptoms include polyuria, polydipsia, and weight loss.
    explanation: The reference clearly states that polydipsia is a symptom of Type 1 Diabetes Mellitus, supporting the statement that it is a frequent systemic occurrence.
  phenotype_term:
    preferred_term: Polydipsia
    term:
      id: HP:0001959
      label: Polydipsia
- category: Endocrine
  frequency: OCCASIONAL
  name: Diabetic Ketoacidosis
  notes: Life-threatening complication of insulin deficiency
  sequelae:
  - target: Abdominal Pain
  - target: Vomiting
  - target: Rapid Breathing
  - target: Confusion
  evidence:
  - reference: PMID:12474677
    reference_title: "[Diabetic ketoacidosis]."
    supports: PARTIAL
    snippet: Diabetic ketoacidosis is an emergency medical condition that can be life-threatening if not treated properly. Diabetic ketoacidosis occurs most often in patients with type 1 diabetes (formerly called insulin-dependent diabetes mellitus); however, its occurrence in patients with type 2 diabetes (formerly called noninsulin-dependent diabetes mellitus) is not as rare as was once thought.
    explanation: The literature supports that diabetic ketoacidosis is a life-threatening complication of type 1 diabetes and mentions symptoms such as abdominal pain and vomiting. However, it does not specify the frequency as 'occasional'.
  - reference: PMID:17627511
    reference_title: "Brittle type 1 diabetes mellitus."
    supports: PARTIAL
    snippet: A small group of patients affected by type 1 diabetes mellitus is characterized by a severe instability of glycemic values with frequent and unpredictable hypoglycemic and/or ketoacidosis episodes which cannot be explained by errors of patients or diabetologists.
    explanation: This reference supports the occurrence of diabetic ketoacidosis in type 1 diabetes and mentions its life-threatening nature but does not confirm the frequency as 'occasional'.
  - reference: PMID:15137354
    reference_title: "Pathophysiology of diabetes mellitus."
    supports: PARTIAL
    snippet: The article points out the signs and symptoms to be aware of when the person is in the acute state of diabetic ketoacidosis, hyperglycemic hyperosmolar nonketotic coma (or state), and severe hypoglycemia.
    explanation: The reference confirms that diabetic ketoacidosis is a life-threatening complication of type 1 diabetes and includes symptoms like confusion and rapid breathing but does not specify the frequency as 'occasional'.
  - reference: PMID:35466445
    reference_title: "Diabetic ketoacidosis as a unique initial presentation of cystic fibrosis."
    supports: PARTIAL
    snippet: Diabetic ketoacidosis as a unique initial presentation of cystic fibrosis.
    explanation: This reference indicates that diabetic ketoacidosis can be a presentation in type 1 diabetes but does not address the frequency or the specific symptoms listed.
  phenotype_term:
    preferred_term: Diabetic Ketoacidosis
    term:
      id: HP:0001953
      label: Diabetic ketoacidosis
- category: Ophthalmologic
  frequency: OCCASIONAL
  name: Diabetic Retinopathy
  notes: Leading cause of blindness, due to chronic hyperglycemia
  evidence:
  - reference: PMID:24864506
    reference_title: "[Diabetic retinopathy in patients with type 1 diabetes mellitus]."
    supports: NO_EVIDENCE
    snippet: Diabetes mellitus (DM), due to its epidemic prevalence and high occurrence of associated disability, is now one of the priority medical and social problems. Incapacitating manifestations of diabetes include visual impairment. Thus, diabetic retinopathy (DR), a late nonspecific vascular complication of DM, is the leading cause of blindness in the working-age population.
    explanation: The literature mentions diabetic retinopathy as a leading cause of blindness in the working-age population but does not provide specific information on its frequency in Type I Diabetes.
  - reference: PMID:37469057
    reference_title: "Ocular Complications Associated With Diabetes And The Risk Of Sustainable Blindness; A Real World Analysis."
    supports: NO_EVIDENCE
    snippet: The commonest morbidity was cataract12,607(28.8%), followed by refractive errors 8,508(19.5%), vision-threatening diabetic retinopathy 2,553(5.83%) and suspected glaucoma 1,211(2.76%).
    explanation: The study provides data on the prevalence of diabetic retinopathy in a diabetic population but does not specify it as occasional in Type I Diabetes.
  - reference: PMID:38272591
    reference_title: "Acute and Chronic Adverse Outcomes of Type 1 Diabetes."
    supports: NO_EVIDENCE
    snippet: Type 1 diabetes is associated with both acute and chronic complications. Acute complications include diabetic ketoacidosis and severe hypoglycemia. Chronic complications can be microvascular or macrovascular. Microvascular complications include retinopathy, nephropathy, and neuropathy.
    explanation: The article mentions retinopathy as a complication of Type 1 diabetes but does not specify its frequency as occasional.
  - reference: PMID:29682912
    reference_title: "Diabetic macular oedema: under-represented in the genetic analysis of diabetic retinopathy."
    supports: NO_EVIDENCE
    snippet: Diabetic retinopathy, a complication of both type 1 and type 2 diabetes, is a complex disease and is one of the leading causes of blindness in adults worldwide.
    explanation: The literature mentions diabetic retinopathy as a complication of Type 1 and Type 2 diabetes but does not specify its frequency as occasional.
- category: Neurologic
  frequency: OCCASIONAL
  name: Diabetic Neuropathy
  notes: Nerve damage from chronic hyperglycemia
  evidence:
  - reference: PMID:28159476
    reference_title: "Treatment induced neuropathy of diabetes-Long term implications in type 1 diabetes."
    supports: PARTIAL
    snippet: Aggressive glucose control can result in treatment induced neuropathy of diabetes (TIND) if glycemic control is achieved too quickly.
    explanation: This reference supports the statement by indicating that aggressive glycemic control can lead to diabetic neuropathy, which is a neurologic complication of Type I Diabetes.
  - reference: PMID:33071962
    reference_title: "Glycemic Variability and Diabetic Neuropathy in Young Adults With Type 1 Diabetes."
    supports: SUPPORT
    snippet: Glycemic variability (GV) may attribute to the pathogenesis of diabetic neuropathy.
    explanation: This reference supports the statement that diabetic neuropathy is a neurologic complication associated with glycemic variability, which can be linked to chronic hyperglycemia.
  - reference: PMID:33715053
    reference_title: "Brain Health in Children with Type 1 Diabetes: Risk and Protective Factors."
    supports: NO_EVIDENCE
    snippet: Emerging evidence suggests that hyperglycemia and time in range may be more important for brain development than episodes of hypoglycemia.
    explanation: This reference supports the statement by highlighting the role of hyperglycemia in neurocognitive complications, which can be related to diabetic neuropathy in Type I Diabetes.
  - reference: PMID:23506377
    reference_title: "Insulin neuritis and diabetic cachectic neuropathy: a review."
    supports: PARTIAL
    snippet: '''Insulin neuritis'' or ''treatment induced neuropathy'' is a reversible disorder characterised by acute severe distal limb pain, peripheral nerve fibre damage and autonomic dysfunction, preceded by a period of rapid glycaemic control.'
    explanation: This reference supports the statement by describing insulin neuritis, a form of diabetic neuropathy, which is a neurologic complication associated with glycemic control.
- category: Renal
  frequency: OCCASIONAL
  name: Diabetic Nephropathy
  notes: Kidney damage from chronic hyperglycemia
  evidence:
  - reference: PMID:23290727
    reference_title: "Clinical manifestations and natural history of diabetic kidney disease."
    supports: NO_EVIDENCE
    snippet: Renal failure in type 2 diabetes has been termed 'a medical catastrophe of worldwide dimension'.
    explanation: This study primarily discusses renal failure in type 2 diabetes, not type 1 diabetes.
  - reference: PMID:27903991
    reference_title: "Role of Oxidative Stress and Inflammatory Factors in Diabetic Kidney Disease."
    supports: PARTIAL
    snippet: Diabetic nephropathy (DN) is a serious complication of diabetes mellitus, and its prevalence has been increasing in developed countries.
    explanation: The study mentions diabetic nephropathy as a serious complication of diabetes mellitus in general, without specifying the frequency in type 1 diabetes.
  - reference: PMID:1490695
    reference_title: "Diabetic retinopathy, nephropathy and neuropathy. Generalized vascular damage in insulin-dependent diabetic patients."
    supports: PARTIAL
    snippet: The most serious complication of diabetes mellitus is clinical nephropathy.
    explanation: The study highlights nephropathy as a serious complication of diabetes mellitus but does not specify its frequency in type 1 diabetes.
  - reference: PMID:30833370
    reference_title: "Risk Factors for Kidney Disease in Type 1 Diabetes."
    supports: PARTIAL
    snippet: higher mean glycemic exposure was the strongest determinant of kidney disease among the modifiable risk factors.
    explanation: The study identifies glycemic control as a significant factor for kidney disease in type 1 diabetes but does not specify the frequency of diabetic nephropathy.
- category: Renal
  name: Glucosuria
  frequency: FREQUENT
  phenotype_term:
    preferred_term: Glucosuria
    term:
      id: HP:0003076
      label: Glycosuria
- category: Systemic
  name: Fatigue
  frequency: FREQUENT
  phenotype_term:
    preferred_term: Fatigue
    term:
      id: HP:0012378
      label: Fatigue
- category: Ocular
  name: Retinopathy
  frequency: FREQUENT
  phenotype_term:
    preferred_term: Retinopathy
    term:
      id: HP:0000488
      label: Retinopathy
- category: Neurologic
  name: Neuropathy
  frequency: FREQUENT
  phenotype_term:
    preferred_term: Neuropathy
    term:
      id: HP:0009830
      label: Peripheral neuropathy
- category: Renal
  name: Nephropathy
  frequency: FREQUENT
  phenotype_term:
    preferred_term: Nephropathy
    term:
      id: HP:0000112
      label: Nephropathy
- category: Cardiovascular
  name: Cardiovascular Disease
  frequency: FREQUENT
  phenotype_term:
    preferred_term: Cardiovascular Disease
    term:
      id: HP:0001626
      label: Abnormality of the cardiovascular system
- category: Gastrointestinal
  name: Abdominal Pain
  frequency: FREQUENT
  phenotype_term:
    preferred_term: Abdominal Pain
    term:
      id: HP:0002027
      label: Abdominal pain
- category: Gastrointestinal
  name: Vomiting
  frequency: FREQUENT
  phenotype_term:
    preferred_term: Vomiting
    term:
      id: HP:0002013
      label: Vomiting
- category: Respiratory
  name: Rapid Breathing
  frequency: FREQUENT
  phenotype_term:
    preferred_term: Rapid Breathing
    term:
      id: HP:0002789
      label: Tachypnea
- category: Neurologic
  name: Confusion
  frequency: FREQUENT
  phenotype_term:
    preferred_term: Confusion
    term:
      id: HP:0001289
      label: Confusion
biochemical:
- name: Blood Glucose
  presence: Elevated
  frequency: VERY_FREQUENT
  evidence:
  - reference: PMID:6378696
    reference_title: "Pre-type I diabetes. Linear loss of beta cell response to intravenous glucose."
    supports: PARTIAL
    snippet: Elevations of fasting blood glucose and peak glucose during oral glucose tolerance tests were not observed until the year before onset of clinically overt diabetes.
    explanation: This reference suggests that elevated blood glucose is present, but only becomes noticeable in the year before the onset of type 1 diabetes, not necessarily 'VERY_FREQUENT' earlier on.
  - reference: PMID:33595181
    reference_title: "Liver chemistries in glycogenic hepatopathy associated with type 1 diabetes mellitus: A systematic review and pooled analysis."
    supports: NO_EVIDENCE
    snippet: Glycogenic hepatopathy (GH) in type 1 diabetes-mellitus (T1DM) is characterized by hepatomegaly and perturbations of liver chemistries (LC) that have not been well studied.
    explanation: The focus of this study is on liver chemistries in glycogenic hepatopathy associated with type 1 diabetes, not specifically on the frequency of elevated blood glucose.
  - reference: PMID:18502304
    reference_title: "Type 1 diabetes, hyperglycaemia, and the heart."
    supports: PARTIAL
    snippet: Type 1 diabetes is associated with a substantially increased risk of cardiovascular disease... microvascular complications...hyperglycaemia is indeed a mediator of cardiovascular risk in type 1 diabetes.
    explanation: This reference supports that elevated blood glucose (hyperglycaemia) is a common and significant factor in type 1 diabetes, indicating that it is 'VERY_FREQUENT'.
- name: Hemoglobin A1c (HbA1c)
  presence: Elevated
  frequency: VERY_FREQUENT
  evidence:
  - reference: PMID:22847316
    reference_title: "1,5-Anhydroglucitol in diabetes mellitus."
    supports: SUPPORT
    snippet: The measure of glycated hemoglobin (HbA1c) concentration is the gold standard of glycemic control index in diabetes management and is well known as a marker for diabetes complications.
    explanation: Hemoglobin A1c is frequently measured in the management of diabetes, including Type I diabetes, and elevated levels are indicative of poor glycemic control.
  - reference: PMID:26397266
    reference_title: "Elevated Hemoglobin A1C Levels Correlate with Blood Glucose Elevation in Diabetic Patients following Local Corticosteroid Injection in the Hand: A Prospective Study."
    supports: SUPPORT
    snippet: Hemoglobin A1c is the accepted measure of long-term plasma glucose control in diabetics (levels >/=7 percent reflect poor blood glucose control).
    explanation: Elevated HbA1c levels are a common indicator used in the management of diabetes, supporting the claim of frequent elevated HbA1c in Type I diabetes.
genetic:
- name: HLA-DQ2
  association: Susceptibility
  notes: HLA-DQ2 is a haplotype-level risk label, not a single HGNC-resolvable gene.
  evidence:
  - reference: PMID:22184118
    reference_title: "Type 1 diabetes-associated HLA-DQ8 transdimer accommodates a unique peptide repertoire."
    supports: SUPPORT
    snippet: HLA-DQ2 and HLA-DQ8 are strongly predisposing haplotypes for type 1 diabetes (T1D).
    explanation: This study identifies HLA-DQ2 as a strongly predisposing haplotype for type 1 diabetes susceptibility.
- name: HLA-DQ8
  association: Susceptibility
  notes: HLA-DQ8 is a haplotype-level risk label, not a single HGNC-resolvable gene.
  evidence:
  - reference: PMID:22184118
    reference_title: "Type 1 diabetes-associated HLA-DQ8 transdimer accommodates a unique peptide repertoire."
    supports: SUPPORT
    snippet: HLA-DQ2 and HLA-DQ8 are strongly predisposing haplotypes for type 1 diabetes (T1D).
    explanation: This statement specifically mentions HLA-DQ8 as a strong predisposing haplotype for type 1 diabetes, supporting the association with susceptibility.
  - reference: PMID:26492519
    reference_title: "The association between the HLA-G 14-bp insertion/deletion polymorphism and type 1 diabetes."
    supports: SUPPORT
    snippet: The DR3-DQ2/DR4-DQ8 genotype conferred the highest detected risk for T1D.
    explanation: This study identifies the DR4-DQ8 genotype as highly associated with a risk for developing type 1 diabetes, thus supporting the genetic susceptibility.
  - reference: PMID:34946827
    reference_title: "Next Generation Sequencing Identifies the HLA-DQA1*03:03 Allele in the Type 1 Diabetes Risk-Associated HLA-DQ8 Serotype."
    supports: SUPPORT
    snippet: The combination of HLA-DQA1*03:01 and DQB1*03:02 alleles (summarized as 'HLA-DQ8') is reported to be among the two most prevalent HLA class II haplotypes in Caucasian type 1 diabetes patients.
    explanation: This reference confirms that HLA-DQ8 is one of the most prevalent haplotypes among type 1 diabetes patients in the studied population, supporting its association with susceptibility.
- name: INS
  gene_term:
    preferred_term: INS
    term:
      id: hgnc:6081
      label: INS
  association: Susceptibility
  notes: Insulin gene; VNTR/INS expression influences central and peripheral tolerance to insulin
  evidence:
  - reference: PMID:15529622
    reference_title: "Strong association of insulin gene INS-VNTR polymorphisms with type 1 diabetes in the Romanian population."
    supports: SUPPORT
    snippet: Our results indicate an exceptionally strong association of the class I INS-VNTR alleles with T1DM for the Romanian population.
    explanation: The study presents evidence of a strong association between INS-VNTR alleles of the insulin gene and susceptibility to type 1 diabetes in the Romanian population.
  - reference: PMID:8934932
    reference_title: "Type I insulin-dependent diabetes mellitus: a model for autoimmune polygenic disorders."
    supports: SUPPORT
    snippet: Genetic susceptibility predominantly results from specific alleles in the HLA complex and insulin gene region.
    explanation: This paper states that genetic susceptibility to insulin-dependent diabetes mellitus predominantly results from specific alleles, including those in the insulin gene region.
  - reference: PMID:11845220
    reference_title: "Genetic linkage and association studies of Type I diabetes: challenges and rewards."
    supports: PARTIAL
    snippet: However, only within the past decade has it been possible to systematically attempt to identify the genes that increase susceptibility to this disorder using linkage and association analysis of genetic markers distributed across the genome.
    explanation: This study discusses the identification of susceptibility genes for type 1 diabetes, including the insulin gene.
  - reference: PMID:11921414
    reference_title: "The insulin gene in diabetes."
    supports: SUPPORT
    snippet: Because insulin has such a central role in the pathogenesis of both forms of diabetes, the insulin gene (INS) has always been considered a candidate susceptibility gene.
    explanation: The paper directly states that the insulin gene is considered a candidate susceptibility gene.
  - reference: PMID:11347740
    reference_title: "Concordance for type 1 diabetes in identical twins is affected by insulin genotype."
    supports: SUPPORT
    snippet: The disease-associated INS genotype (Hph I) was identified in 87.5% of the concordant twins but only in 59.5% (P = 0.005) of the discordant twins.
    explanation: The study demonstrates the presence of a disease-associated INS genotype in a high percentage of concordant twins for type 1 diabetes.
  - reference: PMID:33483996
    reference_title: "De-coding genetic risk variants in type 1 diabetes."
    supports: SUPPORT
    snippet: Over half of the genetic risk has been attributed to the human leukocyte antigen (HLA) class II gene region and to the insulin (INS) gene locus.
    explanation: This article attributes a significant portion of the genetic risk for type 1 diabetes to the insulin (INS) gene locus.
- name: PTPN22
  gene_term:
    preferred_term: PTPN22
    term:
      id: hgnc:9652
      label: PTPN22
  association: Susceptibility
  notes: Tyrosine phosphatase that negatively regulates TCR signaling; risk alleles alter T cell activation thresholds
  evidence:
  - reference: PMID:15734872
    reference_title: "Genetic association between a lymphoid tyrosine phosphatase (PTPN22) and type 1 diabetes."
    supports: SUPPORT
    snippet: The homozygous genotype for the T allele encoding the 620W residue is associated with an increased risk for developing type 1 diabetes
    explanation: This study demonstrates that the PTPN22 R620W polymorphism confers significant genetic susceptibility to type 1 diabetes in Caucasian populations.
- name: IL2RA
  gene_term:
    preferred_term: IL2RA
    term:
      id: hgnc:6008
      label: IL2RA
  association: Susceptibility
  notes: IL-2 receptor alpha chain; modulates regulatory T cell (Treg) fitness and homeostasis
  evidence:
  - reference: PMID:22461703
    reference_title: "Type 1 diabetes-associated IL2RA variation lowers IL-2 signaling and contributes to diminished CD4+CD25+ regulatory T cell function."
    supports: SUPPORT
    snippet: CD4(+)CD25(+) regulatory T cells (Tregs) from individuals with a range of human autoimmune diseases, including type 1 diabetes, are deficient in their ability to control autologous proinflammatory responses
    explanation: This study demonstrates that IL2RA variants associated with type 1 diabetes lead to diminished IL-2 responsiveness and impaired regulatory T cell function.
- name: CTLA4
  gene_term:
    preferred_term: CTLA4
    term:
      id: hgnc:2505
      label: CTLA4
  association: Susceptibility
  notes: Immune-checkpoint receptor that limits T cell activation and promotes tolerance
  evidence:
  - reference: PMID:9353155
    reference_title: "CTLA-4 gene polymorphism confers susceptibility to insulin-dependent diabetes mellitus (IDDM) independently from age and from other genetic or immune disease markers. The Belgian Diabetes Registry."
    supports: SUPPORT
    snippet: the presence of a G-containing CTLA-4 genotype confers a moderate but significant RR for IDDM that is independent of age and genetic or immune disease markers
    explanation: This study demonstrates that CTLA4 gene polymorphisms confer susceptibility to type 1 diabetes independent of other genetic and immune markers.
- name: TYK2
  gene_term:
    preferred_term: TYK2
    term:
      id: hgnc:12440
      label: TYK2
  association: Susceptibility
  notes: Janus-family kinase in type I IFN/JAK signaling; variants affect interferon responses and beta-cell sensitivity
  evidence: []
- name: IFIH1
  gene_term:
    preferred_term: IFIH1
    term:
      id: hgnc:18873
      label: IFIH1
  association: Susceptibility
  notes: Cytosolic viral RNA sensor (MDA5) implicated in antiviral signaling and linkage to autoimmune risk
  evidence: []
- name: BACH2
  gene_term:
    preferred_term: BACH2
    term:
      id: hgnc:14078
      label: BACH2
  association: Susceptibility
  notes: Transcriptional regulator controlling immune-cell differentiation and tolerance maintenance
  evidence: []
- name: TNFAIP3
  gene_term:
    preferred_term: TNFAIP3
    term:
      id: hgnc:11896
      label: TNFAIP3
  association: GWAS
  notes: Encodes A20, a ubiquitin-editing enzyme that negatively regulates NF-kB signaling
- name: EGR2
  gene_term:
    preferred_term: EGR2
    term:
      id: hgnc:3239
      label: EGR2
  association: GWAS
  notes: Transcription factor involved in T cell anergy and peripheral tolerance
- name: IRF4
  gene_term:
    preferred_term: IRF4
    term:
      id: hgnc:6119
      label: IRF4
  association: GWAS
  notes: Transcription factor essential for Th17 and Th2 cell differentiation and plasma cell development
- name: IKZF1
  gene_term:
    preferred_term: IKZF1
    term:
      id: hgnc:13176
      label: IKZF1
  association: GWAS
  notes: Ikaros transcription factor essential for lymphocyte development and differentiation
environmental:
- name: Viral Infections
  notes: May trigger the autoimmune response in genetically susceptible individuals
  evidence:
  - reference: PMID:23393684
    reference_title: "Viral infections and diabetes."
    supports: SUPPORT
    snippet: One of the environmental risk factors identified by a series of independent studies is represented by viral infection, with strong evidence showing that viruses can indeed infect pancreatic beta cells with consequent effects ranging from functional damage to cell death.
    explanation: This reference mentions that viral infections are a strong environmental risk factor for Type I Diabetes, affecting pancreatic beta cells which can lead to autoimmunity.
  - reference: PMID:22891485
    reference_title: "[Type 1 diabetes: from genetic predisposition to hypothetical environmental triggers]."
    supports: PARTIAL
    snippet: Environmental factors must be involved such as viral infections, toxins from food, cow milk during childhood (instead of breast feeding) or vitamin D deficiency.
    explanation: This reference suggests that viral infections are among several environmental factors associated with Type I Diabetes, but does not pinpoint them as the singularly most critical factor.
  - reference: PMID:34942009
    reference_title: "Parainfluenza viruses: A trigger for type 1 diabetes new onset?"
    supports: SUPPORT
    snippet: Enteroviruses, especially CoxB and Echo, are most represented.
    explanation: This reference supports the role of viral infections in Type I Diabetes, mentioning enteroviruses among others.
  - reference: PMID:18357774
    reference_title: "The CVB and etiology of type 1 diabetes."
    supports: PARTIAL
    snippet: The most often cited environmental agents implicated as initiators of T1D are the human enteroviruses, in particular the group B coxsackieviruses (CVB).
    explanation: This reference supports the role of enteroviruses as environmental triggers for Type I Diabetes but notes that evidence is not firmly established.
  - reference: PMID:24003924
    reference_title: "Infectious triggers in type 1 diabetes: is there a case for epitope mimicry?"
    supports: PARTIAL
    snippet: Enteroviruses are proposed candidate triggers due to temporal correlations between infection and T1D autoimmunity and to detection of viral proteins in diseased islets.
    explanation: The reference suggests enteroviruses as potential triggers for Type I Diabetes but emphasizes the need for more robust evidence for a causative relationship.
  - reference: PMID:11334504
    reference_title: "Type 1A diabetes induced by infection and immunization."
    supports: SUPPORT
    snippet: Congenital rubella is the only infection clearly associated with the development of type 1A diabetes.
    explanation: This reference specifically mentions congenital rubella as an infection clearly associated with Type I Diabetes, supporting the statement.
  - reference: PMID:31401790
    reference_title: "Genetic and Environmental Interaction in Type 1 Diabetes: a Relationship Between Genetic Risk Alleles and Molecular Traits of Enterovirus Infection?"
    supports: PARTIAL
    snippet: The natural history of human type 1 diabetes (T1D) and the documented associations between virus infections (in particular the enteroviruses) and disease development.
    explanation: This reference discusses associations between viral infections, particularly enteroviruses, and Type I Diabetes development, but indicates a need for further studies.
  - reference: PMID:17691946
    reference_title: "Viral infection--a cure for type 1 diabetes?"
    supports: SUPPORT
    snippet: evidence from various animal models suggests that viruses can indeed initiate or accelerate autoimmune diseases, such as type 1 diabetes...
    explanation: This reference provides evidence from animal models that support the initiation or acceleration of Type I Diabetes by viruses.
  - reference: PMID:36950864
    reference_title: "COVID-19 as a Trigger for Type 1 Diabetes."
    supports: SUPPORT
    snippet: Convincing evidence indicates that viruses are associated with T1D development and progression.
    explanation: This reference provides convincing evidence that viral infections, including SARS-CoV-2, may trigger or unmask Type I Diabetes.
  exposure_term:
    preferred_term: Viral infection exposure
    term:
      id: ECTO:3000001
      label: exposure to virus
- name: Early Dietary Factors
  notes: Possible risk factors include early exposure to cow's milk and gluten
  evidence:
  - reference: PMID:8741809
    reference_title: "The relationship between cow's milk exposure and type 1 diabetes."
    supports: PARTIAL
    snippet: There is a relationship between early cow's milk exposure and the development of Type 1 diabetes in humans, and between early cow's milk exposure and the development of autoimmune diabetes in rodent models of Type 1 diabetes.
    explanation: The reference supports early dietary factors such as cow's milk exposure but indicates that the data are insufficient to conclude a causal relationship.
  - reference: PMID:26605913
    reference_title: "Primary Prevention of Celiac Disease: Environmental Factors with a Focus on Early Nutrition."
    supports: NO_EVIDENCE
    snippet: Recently, the results of two large randomized trials have shown that breastfeeding in general, breastfeeding during gluten introduction, and early or delayed gluten introduction do not influence the total risk of CD in genetically predisposed individuals.
    explanation: The reference suggests that early or delayed introduction of gluten does not influence the risk of celiac disease, type 1 diabetes mellitus, and wheat allergy, providing no supporting evidence for early dietary factors as risk factors for Type 1 diabetes.
  - reference: PMID:20640941
    reference_title: "Infant and childhood diet and type 1 diabetes risk: recent advances and prospects."
    supports: PARTIAL
    snippet: Given that type 1 diabetes, and its preclinical autoimmunity, appear early in life, infant and childhood diet have been implicated as potential initiating exposures in the etiology of the disease.
    explanation: The reference implicates early dietary factors in the risk of Type 1 diabetes but also highlights inconsistencies and the need for further research.
  - reference: PMID:17203405
    reference_title: "Environmental factors in the development of Type 1 diabetes."
    supports: PARTIAL
    snippet: Enteroviruses (especially Coxsackie B virus), breastfeeding, the early presence or lack of certain foods, birth weight, childhood over-nutrition, maternal islet autoimmunity, and negative stress events have been shown to be related to the prevalence of T1D.
    explanation: The reference supports a link between early dietary factors and Type 1 diabetes but does not provide conclusive evidence.
  exposure_term:
    preferred_term: Early dietary exposure
treatments:
- name: Insulin Therapy
  description: Essential treatment to replace the missing insulin and regulate blood glucose levels.
  evidence:
  - reference: PMID:21584767
    reference_title: "Insulin therapy."
    supports: SUPPORT
    snippet: Insulin therapy is a vital hormone replacement therapy in type 1 diabetes mellitus.
  - reference: PMID:36476434
    reference_title: "Therapies for Type 1 Diabetes: Is a Cure Possible?"
    supports: SUPPORT
    snippet: The current standard method for type 1 diabetes (T1D) management majorly focuses on controlling blood glucose levels with exogeneous insulin administration.
  - reference: PMID:32342453
    reference_title: "Exercise and Type 1 Diabetes."
    supports: SUPPORT
    snippet: T1DM is caused by absolute lack of insulin secretion, so the current treatment for T1DM patients is exogenous insulin replacement therapy.
  - reference: PMID:20723814
    supports: NO_EVIDENCE
    snippet: ''
    explanation: The reference lacks specific details pertaining to treatment.
  - reference: PMID:31426099
    reference_title: "A Technological Revolution: The Integration of New Treatments to Manage Type 1 Diabetes."
    supports: PARTIAL
    snippet: Although a cure for T1D remains the ultimate goal, technology holds the promise of keeping youth with T1D in targeted control and minimize the burden of this chronic medical condition.
    explanation: The reference acknowledges insulin therapy but focuses more on technological advancements rather than confirming insulin therapy as the essential treatment.
  - reference: PMID:28685788
    reference_title: "C-Peptide replacement therapy in type 1 diabetes: are we in the trough of disillusionment?"
    supports: PARTIAL
    snippet: Replacing C-peptide, a hormone normally co-secreted with insulin, has been shown to reduce diabetes-related complications.
    explanation: This reference discusses auxiliary therapy but does not diminish the essential role of insulin therapy.
  - reference: PMID:33970586
    reference_title: "Diabetes: Type 1 Diabetes."
    supports: SUPPORT
    snippet: The mainstay of management is a regimen of multiple daily injections of insulin or continuous subcutaneous insulin delivered via an insulin pump.
  - reference: PMID:15306833
    reference_title: "The reality of glycaemic control in insulin treated diabetes: defining the clinical challenges."
    supports: SUPPORT
    snippet: There is, however, a limit to what can be achieved with existing exogenous insulin therapies due to their imperfect pharmacokinetic and pharmacodynamic profiles
  - reference: PMID:6749365
    reference_title: "Replacement treatment with insulin in diabetes mellitus: problems and promise."
    supports: SUPPORT
    snippet: 'The results of epidemiological and clinical studies of diabetes in man and of studies of experimental diabetes in animals provide strong evidence: (1) that insulin-dependent diabetes mellitus is due to absolute or severe deficiency of insulin; (2) that replacement treatment with insulin is potentially capable of normalizing the metabolic abnormalities; and (3) that normalization of the metabolic abnormalities can be expected to prevent or ameliorate the complications of the disease'
  - reference: PMID:20666700
    reference_title: "Treatment options for paediatric diabetes."
    supports: PARTIAL
    snippet: Insulin is the primary medication in the treatment of type 1 diabetes. New therapeutic options and prevention strategies (cellular therapies, immunomodulation and vaccination) aim to preserve residual beta-cell function.
    explanation: The focus on insulin as primary treatment supports the statement, despite mentioning new therapeutic options.
  treatment_term:
    preferred_term: insulin treatment
    term:
      id: MAXO:0000259
      label: insulin treatment
- name: Blood Glucose Monitoring
  description: Regular monitoring to manage glucose levels effectively.
  evidence:
  - reference: PMID:30215903
    reference_title: "Type 1 Diabetes: Management Strategies."
    supports: SUPPORT
    snippet: There is considerable benefit of tight glucose control in patients with type 1 diabetes mellitus. ... Greater frequency of glucose monitoring and continuous glucose monitoring are both associated with lower A1C levels.
    explanation: The abstract emphasizes the importance of glucose monitoring in managing type 1 diabetes, supporting the statement that regular monitoring is crucial for effective glucose level management.
  - reference: PMID:32256447
    reference_title: "Monitoring of Pediatric Type 1 Diabetes."
    supports: SUPPORT
    snippet: Regular self-monitoring of blood glucose levels, and ketones when indicated, is an essential component of type 1 diabetes (T1D) management.
    explanation: The abstract reaffirms that regular monitoring of blood glucose is essential for managing type 1 diabetes, supporting the statement.
  - reference: PMID:38551884
    reference_title: "[Insulin-treated diabetes in general practice]."
    supports: SUPPORT
    snippet: Blood glucose monitoring has been an integral part of diabetes treatment for many years, whether for type 1 diabetic patients on multiple daily injections of insulin, insulin pumps or artificial pancreas, and now for patients with type 2 diabetes...
    explanation: The abstract describes blood glucose monitoring as a cornerstone in diabetes treatment, which includes the management of type 1 diabetes, thus supporting the statement.
  - reference: PMID:11149158
    reference_title: "Sick-day management in type 1 diabetes."
    supports: SUPPORT
    snippet: Sick-day management requires increased monitoring of blood glucose and assessment for ketosis.
    explanation: The abstract highlights that during illness, increased blood glucose monitoring is necessary for managing type 1 diabetes, further supporting the statement about regular monitoring.
- name: Lifestyle Modifications
  description: Maintaining a balanced diet, regular physical activity, and adherence to treatment plans.
  evidence:
  - reference: PMID:9314011
    reference_title: "Lifestyle modifications for diabetes management."
    supports: PARTIAL
    snippet: Nutrition therapy and physical activity can assist persons with diabetes to achieve metabolic goals. Several lifestyle strategies can be used.
    explanation: The text supports the assertion that maintaining a balanced diet and regular physical activity can assist in managing diabetes through lifestyle modifications.
  - reference: PMID:16529680
    reference_title: "Managing the athlete with type 1 diabetes."
    supports: SUPPORT
    snippet: The patient and physician must work together to optimize glucose control involving both insulin administration and caloric intake. Exercise has numerous benefits and the type 1 diabetic should take advantage of these benefits.
    explanation: This supports the statement that lifestyle modifications, including diet and physical activity, are important in managing type 1 diabetes.
  - reference: PMID:24485215
    reference_title: "Lifestyle and cardiometabolic risk in adults with type 1 diabetes: a review."
    supports: PARTIAL
    snippet: Poor lifestyle habits (poor diet quality, sedentary behaviours and smoking) are known to be driving factors for increased CMR factors in the general population.
    explanation: The text underlines the significance of maintaining a good lifestyle, including a balanced diet and physical activity, as part of diabetes management.
  - reference: PMID:32312302
    reference_title: "Lifestyle changes and glycemic control in type 1 diabetes mellitus: a trial protocol with factorial design approach."
    supports: SUPPORT
    snippet: Innovative, cost-effective interventions along with beneficial lifestyle modifications can improve home-based self-monitoring of blood glucose in T1D patients.
    explanation: This reference highlights the role of lifestyle modifications in managing type 1 diabetes through controlling blood glucose levels.
  - reference: PMID:37820077
    reference_title: "Treating obesity in type 1 diabetes mellitus - review of efficacy and safety."
    supports: NO_EVIDENCE
    snippet: Weight loss treatments provide a wide-range of benefits in reducing both morbidity and mortality in those who are obese.
    explanation: It mentions lifestyle interventions as a part of weight loss treatments that benefit T1D management, highlighting their efficacy and safety.
  treatment_term:
    preferred_term: dietary intervention
    term:
      id: MAXO:0000088
      label: dietary intervention
- name: Immunotherapy (Teplizumab)
  description: T-cell-targeting therapy that delays progression from stage 2 to stage 3 disease by approximately 2-3 years in early-stage patients.
  notes: FDA-approved 2022 for delaying clinical onset in presymptomatic individuals
  evidence:
  - reference: PMID:36877454
    reference_title: "Teplizumab: First Approval."
    supports: SUPPORT
    snippet: In November 2022, teplizumab was approved in the USA to delay the onset of Stage 3 T1D in adults and pediatric patients 8 years of age and older with Stage 2 T1D
    explanation: This article documents the FDA approval of teplizumab as the first immunotherapy for delaying type 1 diabetes progression.
- name: Continuous Glucose Monitoring
  description: Real-time glucose monitoring systems for improved glycemic control and reduced hypoglycemic events.
  notes: Associated with lower HbA1c levels and improved time in range
  evidence:
  - reference: PMID:34872983
    reference_title: "Universal Subsidized Continuous Glucose Monitoring Funding for Young People With Type 1 Diabetes: Uptake and Outcomes Over 2 Years, a Population-Based Study."
    supports: SUPPORT
    snippet: After CGM introduction, the odds ratio (OR) of achieving the HbA1c target of <7.0% improved at 12 months (OR 2.5, P < 0.001) and was maintained at 24 months
    explanation: This population-based study demonstrates that continuous glucose monitoring significantly improves glycemic control with sustained improvements in HbA1c target achievement.
review_notes: Type 1 diabetes is an immune-mediated disease in which autoreactive CD8+ and CD4+ T cells destroy insulin-producing pancreatic beta cells, leading to absolute insulin deficiency. Interferon signaling (type I and II) plays a central role in beta-cell intrinsic responses, upregulating antigen presentation and chemokine production while downregulating oxidative phosphorylation. The disease is dominated by HLA class II genetic risk, with additional non-HLA loci (INS, PTPN22, IL2RA, CTLA4, TYK2, IFIH1, BACH2) contributing to immune regulation and beta-cell susceptibility. The natural history spans three stages from silent autoimmunity (stage 1) through dysglycemia (stage 2) to symptomatic hyperglycemia (stage 3). Teplizumab, a T-cell-targeting immunotherapy approved in 2022, can delay progression by approximately 2-3 years in early-stage disease.
disease_term:
  preferred_term: type 1 diabetes mellitus
  term:
    id: MONDO:0005147
    label: type 1 diabetes mellitus
classifications:
  harrisons_chapter:
  - classification_value: endocrine system disorder
  - classification_value: diabetes mellitus
  - classification_value: autoimmune disease