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Diabetes, Metabolic Syndrome and... 2023Type 2 diabetes mellitus (T2DM) is one of the most widespread diseases in Western countries, and its incidence is constantly increasing. Epidemiological studies have... (Review)
Review
Type 2 diabetes mellitus (T2DM) is one of the most widespread diseases in Western countries, and its incidence is constantly increasing. Epidemiological studies have shown that in the next 20 years. The number of subjects affected by T2DM will double. In recent years, owing to the development and improvement in methods for studying the genome, several authors have evaluated the association between monogenic or polygenic genetic alterations and the development of metabolic diseases and complications. In addition, sedentary lifestyle and socio-economic and pandemic factors have a great impact on the habits of the population and have significantly contributed to the increase in the incidence of metabolic disorders, obesity, T2DM, metabolic syndrome, and liver steatosis. Moreover, patients with type 2 diabetes appear to respond to antihyperglycemic drugs. Only a minority of patients could be considered true non-responders. Thus, it appears clear that the main aim of precision medicine in T2DM is to identify patients who can benefit most from a specific drug class more than from the others. Precision medicine is a discipline that evaluates the applicability of genetic, lifestyle, and environmental factors to disease development. In particular, it evaluated whether these factors could affect the development of diseases and their complications, response to diet, lifestyle, and use of drugs. Thus, the objective is to find prevention models aimed at reducing the incidence of pathology and mortality and therapeutic personalized approaches, to obtain a greater probability of response and efficacy. This review aims to evaluate the applicability of precision medicine for T2DM, a healthcare burden in many countries.
PubMed: 38028995
DOI: 10.2147/DMSO.S390752 -
Journal of Molecular Cell Biology Nov 2023A small fraction of patients diagnosed with obesity or diabetes mellitus has an underlying monogenic cause. Here, we constructed a targeted gene panel consisting of 83...
A small fraction of patients diagnosed with obesity or diabetes mellitus has an underlying monogenic cause. Here, we constructed a targeted gene panel consisting of 83 genes reported to be causative for monogenic obesity or diabetes. We performed this panel in 481 patients to detect causative variants and compared these results with whole-exome sequencing (WES) data available for 146 of these patients. The coverage of targeted gene panel sequencing was significantly higher than that of WES. The diagnostic yield in patients sequenced by the panel was 32.9% with subsequent WES leading to three additional diagnoses with two novel genes. In total, 178 variants in 83 genes were detected in 146 patients by targeted sequencing. Three of the 178 variants were missed by WES, although the WES-only approach had a similar diagnostic yield. For the 335 samples only receiving targeted sequencing, the diagnostic yield was 32.2%. In conclusion, taking into account the lower costs, shorter turnaround time, and higher quality of data, targeted sequencing is a more effective screening method for monogenic obesity and diabetes compared to WES. Therefore, this approach could be routinely established and used as a first-tier test in clinical practice for specific patients.
Topics: Humans; Mutation; Exome Sequencing; Exome; Diabetes Mellitus; Obesity
PubMed: 37327085
DOI: 10.1093/jmcb/mjad040 -
NPJ Parkinson's Disease Sep 2023The Global Parkinson's Genetics Program (GP2) will genotype over 150,000 participants from around the world, and integrate genetic and clinical data for use in...
The Global Parkinson's Genetics Program (GP2) will genotype over 150,000 participants from around the world, and integrate genetic and clinical data for use in large-scale analyses to dramatically expand our understanding of the genetic architecture of PD. This report details the workflow for cohort integration into the complex arm of GP2, and together with our outline of the monogenic hub in a companion paper, provides a generalizable blueprint for establishing large scale collaborative research consortia.
PubMed: 37699923
DOI: 10.1038/s41531-023-00533-w -
International Journal of Obesity (2005) Jun 2024The genetic architecture of extreme non-syndromic obesity in adults remains to be elucidated. A range of genes are known to cause monogenic obesity, but even when...
BACKGROUND/OBJECTIVE
The genetic architecture of extreme non-syndromic obesity in adults remains to be elucidated. A range of genes are known to cause monogenic obesity, but even when pathogenic mutations are present, there may be variable penetrance.
METHODS
Whole-exome sequencing (WES) was carried out on a 15-year-old male proband of Pakistani ancestry who had severe obesity. This was followed by family segregation analysis, using Sanger sequencing. We also undertook re-analysis of WES data from 91 unrelated adults with severe obesity (86% white European ancestry) from the Personalised Medicine for Morbid Obesity (PMMO) cohort, recruited from the UK National Health Service.
RESULTS
We identified an oligogenic mode of inheritance of obesity in the proband's family-this provided the impetus to reanalyze existing sequence data in a separate dataset. Analysis of PMMO participant data revealed two further patients who carried more than one rare, predicted-deleterious mutation in a known monogenic obesity gene. In all three cases, the genes involved had known autosomal dominant inheritance, with incomplete penetrance.
CONCLUSION
Oligogenic inheritance may explain some of the variable penetrance in Mendelian forms of obesity. We caution clinicians and researchers to avoid confining sequence analysis to individual genes and, in particular, not to stop looking when the first potentially-causative mutation is found.
Topics: Humans; Male; Adolescent; Obesity, Morbid; Adult; Exome Sequencing; Pedigree; Female; Genetic Predisposition to Disease; Mutation; Penetrance; United Kingdom; Pakistan; Multifactorial Inheritance
PubMed: 38297031
DOI: 10.1038/s41366-024-01476-9 -
Nature Metabolism Feb 2024The prevalence of youth-onset type 2 diabetes (T2D) and childhood obesity has been rising steadily, producing a growing public health concern that disproportionately...
The prevalence of youth-onset type 2 diabetes (T2D) and childhood obesity has been rising steadily, producing a growing public health concern that disproportionately affects minority groups. The genetic basis of youth-onset T2D and its relationship to other forms of diabetes are unclear. Here we report a detailed genetic characterization of youth-onset T2D by analysing exome sequences and common variant associations for 3,005 individuals with youth-onset T2D and 9,777 adult control participants matched for ancestry, including both males and females. We identify monogenic diabetes variants in 2.4% of individuals and three exome-wide significant (P < 2.6 × 10) gene-level associations (HNF1A, MC4R, ATXN2L). Furthermore, we report rare variant association enrichments within 25 gene sets related to obesity, monogenic diabetes and β-cell function. Many youth-onset T2D associations are shared with adult-onset T2D, but genetic risk factors of all frequencies-and rare variants in particular-are enriched within youth-onset T2D cases (5.0-fold increase in the rare variant and 3.4-fold increase in common variant genetic liability relative to adult-onset cases). The clinical presentation of participants with youth-onset T2D is influenced in part by the frequency of genetic risk factors within each individual. These findings portray youth-onset T2D as a heterogeneous disease situated on a spectrum between monogenic diabetes and adult-onset T2D.
Topics: Male; Adult; Female; Humans; Adolescent; Child; Diabetes Mellitus, Type 2; Pediatric Obesity; Exome; Genome-Wide Association Study; Biology
PubMed: 38278947
DOI: 10.1038/s42255-023-00970-0 -
BMJ Open Diabetes Research & Care Jun 2024We designed and implemented a patient-centered, data-driven, holistic care model with evaluation of its impacts on clinical outcomes in patients with young-onset type 2... (Randomized Controlled Trial)
Randomized Controlled Trial
Precision Medicine to Redefine Insulin Secretion and Monogenic Diabetes-Randomized Controlled Trial (PRISM-RCT) in Chinese patients with young-onset diabetes: design, methods and baseline characteristics.
INTRODUCTION
We designed and implemented a patient-centered, data-driven, holistic care model with evaluation of its impacts on clinical outcomes in patients with young-onset type 2 diabetes (T2D) for which there is a lack of evidence-based practice guidelines.
RESEARCH DESIGN AND METHODS
In this 3-year Precision Medicine to Redefine Insulin Secretion and Monogenic Diabetes-Randomized Controlled Trial, we evaluate the effects of a multicomponent care model integrating use of information and communication technology (Joint Asia Diabetes Evaluation (JADE) platform), biogenetic markers and patient-reported outcome measures in patients with T2D diagnosed at ≤40 years of age and aged ≤50 years. The JADE-PRISM group received 1 year of specialist-led team-based management using treatment algorithms guided by biogenetic markers (genome-wide single-nucleotide polymorphism arrays, exome-sequencing of 34 monogenic diabetes genes, C-peptide, autoantibodies) to achieve multiple treatment goals (glycated hemoglobin (HbA1c) <6.2%, blood pressure <120/75 mm Hg, low-density lipoprotein-cholesterol <1.2 mmol/L, waist circumference <80 cm (women) or <85 cm (men)) in a diabetes center setting versus usual care (JADE-only). The primary outcome is incidence of all diabetes-related complications.
RESULTS
In 2020-2021, 884 patients (56.6% men, median (IQR) diabetes duration: 7 (3-12) years, current/ex-smokers: 32.5%, body mass index: 28.40±5.77 kg/m, HbA1c: 7.52%±1.66%, insulin-treated: 27.7%) were assigned to JADE-only (n=443) or JADE-PRISM group (n=441). The profiles of the whole group included positive family history (74.7%), general obesity (51.4%), central obesity (79.2%), hypertension (66.7%), dyslipidemia (76.4%), albuminuria (35.4%), estimated glomerular filtration rate <60 mL/min/1.73 m (4.0%), retinopathy (13.8%), atherosclerotic cardiovascular disease (5.2%), cancer (3.1%), emotional distress (26%-38%) and suboptimal adherence (54%) with 5-item EuroQol for Quality of Life index of 0.88 (0.87-0.96). Overall, 13.7% attained ≥3 metabolic targets defined in secondary outcomes. In the JADE-PRISM group, 4.5% had pathogenic/likely pathogenic variants of monogenic diabetes genes; 5% had autoantibodies and 8.4% had fasting C-peptide <0.2 nmol/L. Other significant events included low/large birth weight (33.4%), childhood obesity (50.7%), mental illness (10.3%) and previous suicide attempts (3.6%). Among the women, 17.3% had polycystic ovary syndrome, 44.8% required insulin treatment during pregnancy and 17.3% experienced adverse pregnancy outcomes.
CONCLUSIONS
Young-onset diabetes is characterized by complex etiologies with comorbidities including mental illness and lifecourse events.
TRIAL REGISTRATION NUMBER
NCT04049149.
Topics: Humans; Female; Male; Diabetes Mellitus, Type 2; Adult; Precision Medicine; Insulin Secretion; Middle Aged; China; Age of Onset; Young Adult; Insulin; Hypoglycemic Agents; Follow-Up Studies; Blood Glucose; Glycated Hemoglobin; Asian People; Biomarkers; Prognosis; East Asian People
PubMed: 38901858
DOI: 10.1136/bmjdrc-2024-004120 -
The Journal of Clinical Investigation Jan 2024Melanocortin 4 receptor (MC4R) mutations are the most common cause of human monogenic obesity and are associated with hyperphagia and increased linear growth. While MC4R...
Melanocortin 4 receptor (MC4R) mutations are the most common cause of human monogenic obesity and are associated with hyperphagia and increased linear growth. While MC4R is known to activate Gsα/cAMP signaling, a substantial proportion of obesity-associated MC4R mutations do not affect MC4R/Gsα signaling. To further explore the role of specific MC4R signaling pathways in the regulation of energy balance, we examined the signaling properties of one such mutant, MC4R (F51L), as well as the metabolic consequences of MC4RF51L mutation in mice. The MC4RF51L mutation produced a specific defect in MC4R/Gq/11α signaling and led to obesity, hyperphagia, and increased linear growth in mice. The ability of a melanocortin agonist to acutely inhibit food intake when delivered to the paraventricular nucleus (PVN) was lost in MC4RF51L mice, as well as in WT mice in which a specific Gq/11α inhibitor was delivered to the PVN; this provided evidence that a Gsα-independent signaling pathway, namely Gq/11α, significantly contributes to the actions of MC4R on food intake and linear growth. These results suggest that a biased MC4R agonist that primarily activates Gq/11α may be a potential agent to treat obesity with limited untoward cardiovascular and other side effects.
Topics: Humans; Mice; Animals; Receptor, Melanocortin, Type 4; Hyperphagia; Obesity; Signal Transduction; Mutation
PubMed: 38175730
DOI: 10.1172/JCI165418 -
A diagnostic conundrum in Bardet-Biedl syndrome: when genetic diagnosis precedes clinical diagnosis.Endocrinology, Diabetes & Metabolism... Oct 2023Bardet-Biedl syndrome (BBS) is a rare, autosomal recessive, multisystem non-motile ciliopathy of progressive onset. It is primarily characterised by rod-cone dystrophy,...
SUMMARY
Bardet-Biedl syndrome (BBS) is a rare, autosomal recessive, multisystem non-motile ciliopathy of progressive onset. It is primarily characterised by rod-cone dystrophy, early-onset obesity and related complications, postaxial polydactyly, renal and genitourinary abnormalities, learning disabilities, and hypogonadism. The diagnosis is based on Beales' modified diagnostic criteria. We present a case of two monozygotic female twins, 17 years of age at presentation, referred for obesity since childhood. The initial hormonal work-up was negative and no dysmorphic features were noted. They were diagnosed with exogenous obesity. However, after ophthalmologic problems became apparent, rod-cone dystrophy was observed and genetic testing was performed. A mutation in the BBS2 gene led to the diagnosis of BBS, although the full diagnostic criteria were not met. This case not only highlights the need to raise awareness for BBS but also exposes two limitations of the current diagnostic standard. The first limitation is the low sensitivity of the clinical diagnostic model, due to the progressive onset and the high variability of the syndrome. The second limitation is the unclear role of genetic testing. As genetic testing becomes more widely available, genetic diagnosis preceding clinical diagnosis will become more common, leading to a diagnostic conundrum. We propose an update of the diagnostic model. A less strict application in the presence of confirmed genetic mutations should be applied, as this could facilitate earlier diagnosis and intervention. This is important because therapeutic agents are being developed that could have a significant impact on quality of life and prognosis.
LEARNING POINTS
Due to the low prevalence, the significant inter-and intrafamilial variation, and the slowly evolving phenotype, monogenic forms of obesity such as Bardet-Biedl syndrome are difficult to diagnose. Despite advances in the understanding of the presentation, pathophysiology and access to accurate genetic characterisation, a substantial number of diagnoses are still made by ophthalmology, as recognition of BBS in other departments of medicine, remains limited. Clinical diagnosis of BBS is based on Beales' modified diagnostic criteria which require the presence of four primary features or three primary features plus two secondary features. This model has its limitations. Due to the progressive onset of clinical symptoms, patients generally do not meet the diagnostic criteria early in life, leading to a delay in diagnosis. In addition, the role of genetic testing remains controversial. However, as it becomes more widely available, genetic diagnosis may precede a full clinical diagnosis. BBS has an impact on the quality of life and prognosis of both the patient and the family. Obesity management strategies are an important part of the multidisciplinary approach, as there is no cure available. Setmelanotide has shown promising results in a phase 3 trial, but its effect in clinical practice remains unproven.
PubMed: 37997784
DOI: 10.1530/EDM-23-0055 -
Obesity Science & Practice Oct 2023While obesity is common in the United States, monogenic obesity is rare, accounting for approximately 5% of individuals with obesity. New targeted therapies for genetic...
BACKGROUND
While obesity is common in the United States, monogenic obesity is rare, accounting for approximately 5% of individuals with obesity. New targeted therapies for genetic forms of obesity are available but there is limited guidance on who requires testing. The aims of this study were to evaluate the prevalence of potentially clinically significant variants among individuals in Pediatric Endocrinology or Medical Weight Center clinics at a single center and to identify clinical characteristics that may make genetic obesity more likely.
METHODS
Children and adults who had a genetic test for obesity, Uncovering Rare Obesity Gene panel, ordered during routine clinic visits from December 2019 to March 2021 were identified.
RESULTS
Of the 139 patients with testing ordered, 117 had available results and clinical data. Over 40% (52/117, 44%) had at least one positive result (variant) with a variant that is considered pathogenic, likely pathogenic, or a variant of uncertain significance. No association was detected between age, sex, race, and body mass index (BMI) or BMI -score with a variant. Twenty-six individuals (22%) had one or more variants in genes associated with Bardet Biedl Syndrome, and 8 (6.8%) of them had pathogenic variants, higher than expected.
CONCLUSION
Overall, clinical suspicion for genetic obesity is important in determining who requires genetic testing but no clinical factors were found to predict results. While obesity is multifactorial, novel medications for genetic forms of obesity indicate the need for evidence-based guidelines for who requires genetic testing for obesity.
PubMed: 37810530
DOI: 10.1002/osp4.671 -
JCI Insight Dec 2023HNF1A haploinsufficiency underlies the most common form of human monogenic diabetes (HNF1A-maturity onset diabetes of the young [HNF1A-MODY]), and hypomorphic HNF1A...
HNF1A haploinsufficiency underlies the most common form of human monogenic diabetes (HNF1A-maturity onset diabetes of the young [HNF1A-MODY]), and hypomorphic HNF1A variants confer type 2 diabetes risk. But a lack of experimental systems for interrogating mature human islets has limited our understanding of how the transcription factor HNF1α regulates adult islet function. Here, we combined conditional genetic targeting in human islet cells, RNA-Seq, chromatin mapping with cleavage under targets and release using nuclease (CUT&RUN), and transplantation-based assays to determine HNF1α-regulated mechanisms in adult human pancreatic α and β cells. Short hairpin RNA-mediated (shRNA-mediated) suppression of HNF1A in primary human pseudoislets led to blunted insulin output and dysregulated glucagon secretion after transplantation in mice, recapitulating phenotypes observed in patients with diabetes. These deficits corresponded with altered expression of genes encoding factors critical for hormone secretion, including calcium channel subunits, ATPase transporters, and extracellular matrix constituents. Additionally, HNF1A loss led to upregulation of transcriptional repressors, providing evidence for a mechanism of transcriptional derepression through HNF1α. CUT&RUN mapping of HNF1α DNA binding sites in primary human islets imputed a subset of HNF1α-regulated genes as direct targets. These data elucidate mechanistic links between HNF1A loss and diabetic phenotypes in mature human α and β cells.
Topics: Animals; Humans; Mice; Diabetes Mellitus, Type 2; Gene Expression Regulation; Insulin; Insulin-Secreting Cells; Pancreas
PubMed: 37943614
DOI: 10.1172/jci.insight.170884