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Journal of Clinical Research in... Oct 2023Adenylate cyclase 3 (ADCY3) gene alterations have been found to be associated with obesity. However, few patients with homozygous mutations have been reported so far,...
Adenylate cyclase 3 (ADCY3) gene alterations have been found to be associated with obesity. However, few patients with homozygous mutations have been reported so far, and the follow-up procedure and treatment options have not been clarified. A 10-month-old female presented with increased appetite and weight gain. She was born from a consanguineous marriage. Weight, height, head circumference measurements and standard deviation scores (SDS) were 19 kg (+6.98 SDS), 82 cm (+3.53 SDS), and 49 cm (+3.07 SDS), respectively. Laboratory tests revealed a fasting glucose level of 103 mg/dL (5.7 mmol/L), insulin level of 25.39 µIU/mL, and Homeostatic Model Assessment for Insulin Resistance (HOMA-IR) value of 6.43. Whole-exome sequencing revealed a novel, homozygous c.1102G>A(p.Asp368Asn) variant in ADCY3. Her parents and healthy sister were heterozygous for the variant. At the age of 2.5 years, neurodevelopmental delay was observed. At the age of 3.5 years, the patient's weight, height, and body mass index values were 49.5 kg (+8.16 SDS), 111 cm (+2.59 SDS), and 40.18 kg/m2 (+6.48 SDS), respectively. Signs of Blount's disease and acanthosis nigricans were distinctive, and she had hyperphagia. She was undergoing speech therapy. Homozygous ADCY3 variants may present with early onset, severe obesity, insulin resistance, and neurodevelopmental delay in children. Severe complications may occur even at young ages. More data regarding the follow-up process and treatment of these patients are needed.
PubMed: 37855273
DOI: 10.4274/jcrpe.galenos.2023.2023-7-2 -
Journal of Diabetes Research 2024Childhood obesity is increasing worldwide and presents as a global health issue due to multiple metabolic comorbidities. About 1% of adolescents with obesity develop...
INTRODUCTION
Childhood obesity is increasing worldwide and presents as a global health issue due to multiple metabolic comorbidities. About 1% of adolescents with obesity develop type 2 diabetes (T2D); however, little is known about the genetic and pathophysiological background at young age. The objective of this study was to assess the prevalence of impaired glucose regulation (IGR) in a large cohort of children and adolescents with obesity and to characterize insulin sensitivity and insulin secretion. We also wanted to investigate adolescents with insulin secretion disorder more closely and analyze possible candidate genes of diabetes in a subcohort.
METHODS
We included children and adolescents with obesity who completed an oral glucose tolerance test (OGTT, glucose + insulin) in the outpatient clinic. We calculated Matsuda index, the area under the curve (AUC (Ins/Glu)), and an oral disposition index (ISSI-2) to estimate insulin resistance and beta-cell function. We identified patients with IGR and low insulin secretion (maximum insulin during OGTT < 200 mU/l) and tested a subgroup using next generation sequencing to identify possible mutations in 103 candidate genes.
RESULTS
The total group consisted of 903 children and adolescents with obesity. 4.5% showed impaired fasting glucose, 9.4% impaired glucose tolerance, and 1.2% T2D. Matsuda index and Total AUC (Ins/Glu) showed a hyperbolic relationship. Out of 39 patients with low insulin secretion, we performed genetic testing on 12 patients. We found five monogenetic defects (ABCC8 ( = 3), GCK ( = 1), and GLI2/PTF1A ( = 1)).
CONCLUSION
Using surrogate parameters of beta-cell function and insulin resistance can help identify patients with insulin secretion disorder. A prevalence of 40% mutations of known diabetes genes in the subgroup with low insulin secretion suggests that at least 1.7% of patients with adolescent obesity have monogenic diabetes. A successful molecular genetic diagnosis can help to improve individual therapy.
Topics: Humans; Child; Adolescent; Pediatric Obesity; Insulin Resistance; Diabetes Mellitus, Type 2; Insulin Secretion; Insulin; Glucose; Molecular Biology; Blood Glucose
PubMed: 38550917
DOI: 10.1155/2024/5558634 -
Clinical and Experimental Pediatrics Dec 2023Recent advances in molecular genetics have advanced our understanding of the molecular mechanisms involved in pediatric endocrine disorders and now play a major role in...
Recent advances in molecular genetics have advanced our understanding of the molecular mechanisms involved in pediatric endocrine disorders and now play a major role in mainstream medical practice. The spectrum of endocrine genetic disorders has 2 extremes: Mendelian and polygenic. Mendelian or monogenic diseases are caused by rare variants of a single gene, each of which exerts a strong effect on disease risk. Polygenic diseases or common traits are caused by the combined effects of multiple genetic variants in conjunction with environmental and lifestyle factors. Testing for a single gene is preferable if the disease is phenotypically and/or geneically homogeneous. Next-generation sequencing (NGS) can be applied to phenotypically and genetically heterogeneous conditions. Genome-wide association studies (GWASs) have examined genetic variants across the entire genome in a large number of individuals who have been matched for population ancestry and assessed for a disease or trait of interest. Common endocrine diseases or traits, such as type 2 diabetes mellitus, obesity, height, and pubertal timing, result from the combined effects of multiple variants in various genes that are frequently found in the general population, each of which contributes a small individual effect. Isolated founder mutations can result from a true founder effect or an extreme reduction in population size. Studies of founder mutations offer powerful advantages for efficiently localizing the genes that underlie Mendelian disorders. The Korean population has settled in the Korean peninsula for thousands of years, and several recurrent mutations have been identified as founder mutations. The application of molecular technology has increased our understanding of endocrine diseases, which have impacted on the practice of pediatric endocrinology related to diagnosis and genetic counseling. This review focuses on the application of genomic research to pediatric endocrine diseases using GWASs and NGS technology for diagnosis and treatment.
PubMed: 37321569
DOI: 10.3345/cep.2022.00948 -
Kidney International Reports May 2024Thousands of pathogenic variants in more than 100 genes can cause kidney cysts with substantial variability in phenotype and risk of subsequent kidney failure. Despite... (Review)
Review
Thousands of pathogenic variants in more than 100 genes can cause kidney cysts with substantial variability in phenotype and risk of subsequent kidney failure. Despite an established genotype-phenotype correlation in cystic kidney diseases, incomplete penetrance and variable disease expressivity are present as is the case in all monogenic diseases. In family members with autosomal dominant polycystic kidney disease (ADPKD), the same causal variant is responsible in all affected family members; however, there can still be striking discordance in phenotype severity. This narrative review explores contributors to within-family discordance in ADPKD severity. Cases of biallelic and digenic inheritance, where 2 rare pathogenic variants in cystogenic genes are coexistent in one family, account for a small proportion of within-family discordance. Genetic background, including cis and trans factors and the polygenic propensity for comorbid disease, also plays a role but has not yet been exhaustively quantified. Environmental exposures, including diet; smoking; alcohol, salt, and protein intake, and comorbid diseases, including obesity, diabetes, hypertension, kidney stones, dyslipidemia, and additional coexistent kidney diseases all contribute to ADPKD phenotypic variability among family members. Given that many of the factors contributing to phenotype variability are preventable, modifiable, or treatable, health care providers and patients need to be aware of these factors and address them in the treatment of ADPKD.
PubMed: 38707833
DOI: 10.1016/j.ekir.2024.01.053 -
Journal of Medical Genetics Dec 2023Alström syndrome (ALMS; #203800) is an ultrarare monogenic recessive disease. This syndrome is associated with variants in the gene, which encodes a... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Alström syndrome (ALMS; #203800) is an ultrarare monogenic recessive disease. This syndrome is associated with variants in the gene, which encodes a centrosome-associated protein involved in the regulation of several ciliary and extraciliary processes, such as centrosome cohesion, apoptosis, cell cycle control and receptor trafficking. The type of variant associated with ALMS is mostly complete loss-of-function variants (97%) and they are mainly located in exons 8, 10 and 16 of the gene. Other studies in the literature have tried to establish a genotype-phenotype correlation in this syndrome with limited success. The difficulty in recruiting a large cohort in rare diseases is the main barrier to conducting this type of study.
METHODS
In this study we collected all cases of ALMS published to date. We created a database of patients who had a genetic diagnosis and an individualised clinical history. Lastly, we attempted to establish a genotype-phenotype correlation using the truncation site of the patient's longest allele as a grouping criteria.
RESULTS
We collected a total of 357 patients, of whom 227 had complete clinical information, complete genetic diagnosis and meta-information on sex and age. We have seen that there are five variants with high frequency, with p.(Arg2722Ter) being the most common variant, with 28 alleles. No gender differences in disease progression were detected. Finally, truncating variants in exon 10 seem to be correlated with a higher prevalence of liver disorders in patients with ALMS.
CONCLUSION
Pathogenic variants in exon 10 of the gene were associated with a higher prevalence of liver disease. However, the location of the variant in the gene does not have a major impact on the phenotype developed by the patient.
Topics: Humans; Alstrom Syndrome; Cell Cycle Proteins; Phenotype; Exons; Genetic Association Studies
PubMed: 37321834
DOI: 10.1136/jmg-2023-109175 -
Molecular Metabolism Jun 2024Metamorphosis is a transition from growth to reproduction, through which an animal adopts adult behavior and metabolism. Yet the neural mechanisms underlying the switch...
OBJECTIVE
Metamorphosis is a transition from growth to reproduction, through which an animal adopts adult behavior and metabolism. Yet the neural mechanisms underlying the switch are unclear. Here we report that neuronal E93, a transcription factor essential for metamorphosis, regulates the adult metabolism, physiology, and behavior in Drosophila melanogaster.
METHODS
To find new neuronal regulators of metabolism, we performed a targeted RNAi-based screen of 70 Drosophila orthologs of the mammalian genes enriched in ventromedial hypothalamus (VMH). Once E93 was identified from the screen, we characterized changes in physiology and behavior when neuronal expression of E93 is knocked down. To identify the neurons where E93 acts, we performed an additional screen targeting subsets of neurons or endocrine cells.
RESULTS
E93 is required to control appetite, metabolism, exercise endurance, and circadian rhythms. The diverse phenotypes caused by pan-neuronal knockdown of E93, including obesity, exercise intolerance and circadian disruption, can all be phenocopied by knockdown of E93 specifically in either GABA or MIP neurons, suggesting these neurons are key sites of E93 action. Knockdown of the Ecdysone Receptor specifically in MIP neurons partially phenocopies the MIP neuron-specific knockdown of E93, suggesting the steroid signal coordinates adult metabolism via E93 and a neuropeptidergic signal. Finally, E93 expression in GABA and MIP neurons also serves as a key switch for the adaptation to adult behavior, as animals with reduced expression of E93 in the two subsets of neurons exhibit reduced reproductive activity.
CONCLUSIONS
Our study reveals that E93 is a new monogenic factor essential for metabolic, physiological, and behavioral adaptation from larval behavior to adult behavior.
Topics: Animals; Female; Male; Adaptation, Physiological; Behavior, Animal; Circadian Rhythm; Drosophila melanogaster; Drosophila Proteins; Metamorphosis, Biological; Neurons; Transcription Factors
PubMed: 38621602
DOI: 10.1016/j.molmet.2024.101939 -
Diagnostics (Basel, Switzerland) Jul 2023Atherogenic dyslipidemia plays a critical role in the development of metabolic syndrome (MetS), being one of its major components, along with central obesity, insulin... (Review)
Review
Atherogenic dyslipidemia plays a critical role in the development of metabolic syndrome (MetS), being one of its major components, along with central obesity, insulin resistance, and hypertension. In recent years, the development of molecular genetics techniques and extended analysis at the genome or exome level has led to important progress in the identification of genetic factors (heritability) involved in lipid metabolism disorders associated with MetS. In this review, we have proposed to present the current knowledge related to the genetic etiology of atherogenic dyslipidemia, but also possible challenges for future studies. Data from the literature provided by candidate gene-based association studies or extended studies, such as genome-wide association studies (GWAS) and whole exome sequencing (WES,) have revealed that atherogenic dyslipidemia presents a marked genetic heterogeneity (monogenic or complex, multifactorial). Despite sustained efforts, many of the genetic factors still remain unidentified (missing heritability). In the future, the identification of new genes and the molecular mechanisms by which they intervene in lipid disorders will allow the development of innovative therapies that act on specific targets. In addition, the use of polygenic risk scores (PRS) or specific biomarkers to identify individuals at increased risk of atherogenic dyslipidemia and/or other components of MetS will allow effective preventive measures and personalized therapy.
PubMed: 37510094
DOI: 10.3390/diagnostics13142348 -
Frontiers in Endocrinology 2023Pediatric obesity has steadily increased in recent decades. Large-scale genome-wide association studies (GWAS) conducted primarily in Eurocentric adult populations have...
INTRODUCTION
Pediatric obesity has steadily increased in recent decades. Large-scale genome-wide association studies (GWAS) conducted primarily in Eurocentric adult populations have identified approximately 100 loci that predispose to obesity and type II diabetes. GWAS in children and individuals of non-European descent, both disproportionately affected by obesity, are fewer. Rare syndromic and monogenic obesities account for only a small portion of childhood obesity, so understanding the role of other genetic variants and their combinations in heritable obesities is key to developing targeted and personalized therapies. Tight and responsive regulation of the cAMP-dependent protein kinase (PKA) signaling pathway is crucial to maintaining healthy energy metabolism, and mutations in PKA-linked genes represent the most common cause of monogenic obesity.
METHODS
For this study, we performed targeted exome sequencing of 53 PKA signaling-related genes to identify variants in genomic DNA from a large, ethnically diverse cohort of obese or metabolically challenged youth.
RESULTS
We confirmed 49 high-frequency variants, including a novel variant in the PDE11A gene (c.152C>T). Several other variants were associated with metabolic characteristics within ethnic groups.
DISCUSSION
We conclude that a PKA pathway-specific variant search led to the identification of several new genetic associations with obesity in an ethnically diverse population.
Topics: Adult; Adolescent; Humans; Child; Pediatric Obesity; Genome-Wide Association Study; Diabetes Mellitus, Type 2; Mutation
PubMed: 38027204
DOI: 10.3389/fendo.2023.1272939 -
Psychiatry Research Jul 2024Fragile X Syndrome (FXS) results from the silencing of the FMR1 gene and is the most prevalent inherited cause of intellectual disability and the most frequent monogenic... (Review)
Review
Fragile X Syndrome (FXS) results from the silencing of the FMR1 gene and is the most prevalent inherited cause of intellectual disability and the most frequent monogenic cause of autism spectrum disorder. It is well established that Fragile X individuals are subjected to a wide array of comorbidities, ranging from cognitive, behavioural, and medical origin. Furthermore, recent studies have also described metabolic impairments in FXS individuals. However, the molecular mechanisms linking FMRP deficiency to improper metabolism are still misunderstood. The endocannabinoidome (eCBome) is a lipid-based signalling system that regulates several functions across the body, ranging from cognition, behaviour and metabolism. Alterations in the eCBome have been described in FXS animal models and linked to neuronal hyperexcitability, a core deficit of the disease. However, the potential link between dysregulation of the eCBome and altered metabolism observed in FXS remains unexplored. As such, this review aims to overcome this issue by describing the most recent finding related to eCBome and metabolic dysfunctions in the context of FXS. A better comprehension of this association will help deepen our understanding of FXS pathophysiology and pave the way for future therapeutic interventions.
Topics: Fragile X Syndrome; Humans; Endocannabinoids; Animals; Metabolic Networks and Pathways; Fragile X Mental Retardation Protein
PubMed: 38763080
DOI: 10.1016/j.psychres.2024.115962 -
European Journal of Endocrinology Oct 2023Mutations in genes encoding proteins located in the leptin/melanocortin pathway have been identified in the rare cases of genetic obesities. Heterozygous variants of...
Mutations in genes encoding proteins located in the leptin/melanocortin pathway have been identified in the rare cases of genetic obesities. Heterozygous variants of MRAP2, encoding a G coupled-protein receptor accessory protein implicated in energy control notably via the melanocortin-4 receptor, have been recently identified. A 24-year-old patient with early-onset severe obesity (body mass index [BMI]: 64 kg/m2) associated with hypertension, respiratory complications, nonalcoholic fatty liver disease, and type 2 diabetes was referred to our department. Sleeve gastrectomy was successful. A new heterozygous variant in MRAP2 (NM_138409.4: c.154G>C/p.G52R) variant was identified in the patient DNA. Functional assessment confirmed that this new variant was pathogenic. We report a new pathogenic loss-of-function mutation in MRAP2 in a patient suffering from a severe multicomplicated obesity. This confirms the metabolic phenotype in patients with this monogenic form of obesity. Longer follow-up will be necessary. Our finding will allow a personalized medicine.
Topics: Humans; Young Adult; Adaptor Proteins, Signal Transducing; Bariatric Surgery; Carrier Proteins; Diabetes Mellitus, Type 2; Obesity; Receptor, Melanocortin, Type 4
PubMed: 37888144
DOI: 10.1093/ejendo/lvad132