Genetic and hereditary aspects of childhood obesity

Leptin receptor Gln223Arg and Lys109Arg polymorphisms may be associated with HBV-related hepatocellular carcinoma risk: A system review and meta-analysis

Increasing evidence has suggested a strong association of hepatocellular carcinoma (HCC) susceptibility and Gln223Arg (rs1137101) and Lys109Arg (rs1137100) polymorphisms in leptin receptor (LEPR) genes. To provide a quantitative assessment for such correlation, we reviewed all related systems and conducted meta-analysis for case and control researches. A literature search of Web of Science, EMBASE, PubMed, Scopus as well as China National Knowledge Infrastructure databases was collected. 95% confidence intervals (95% CIs) together with odds ratios (ORs) were calculated. Five case-control researches consisting of 1323 cases and 1919 control cases were incorporated into meta-analysis. Researches indicated A-allelic and AA genotype of rs1137101 were substantially related to boosted susceptibility of hepatitis B virus (HBV)-related HCC (mutant model, OR = 1.81, 95% CI = 1.36-2.41, p < .001; allelic model, OR = 1.55, 95% CI = 1.32-1.83, p < .001). On the contrary, we observed GG genotype of rs1137101 substantially related to reduced risk of HBV-related HCC (wild model, OR 0.59, 95%CI = 0.46-0.75, p < .001). We observed AA genotype of rs1137100 relevant to boosted HCC risk (mutant model, OR = 1.51, 95%CI = 1.14-2.01, p = .005) as well as in those with HBV-related HCCs (homozygous model, OR = 2.12, 95%CI = 1.49-3.02, p < .001; mutant model, OR = 1.67, 95%CI = 1.23-2.26, p = .001). G-allele and AA genotype of rs1137101 might be in connection with boosted HBV-related HCC susceptibility, and wild-type GG genotype might prevent diseases. AA genotype of rs1137100 might also improve HBV-related HCC susceptibility. Such conclusions ought to be validated by larger and better-designed researches.

Effects of Soy Protein Isolate on Fragile X Phenotypes in Mice

Obesity is a pediatric epidemic that is more prevalent in children with developmental disabilities. We hypothesize that soy protein-based diets increase weight gain and alter neurobehavioral outcomes. Our objective herein was to test matched casein- and soy protein-based purified ingredient diets in a mouse model of fragile X syndrome, Fmr1KO mice. The experimental methods included assessment of growth; 24-7 activity levels; motor coordination; learning and memory; blood-based amino acid, phytoestrogen and glucose levels; and organ weights. The primary outcome measure was body weight. We find increased body weight in male Fmr1KO from postnatal day 6 (P6) to P224, male wild type (WT) from P32-P39, female Fmr1KO from P6-P18 and P168-P224, and female Fmr1HET from P9-P18 as a function of soy. Activity at the beginning of the light and dark cycles increased in female Fmr1HET and Fmr1KO mice fed soy. We did not find significant differences in rotarod or passive avoidance behavior as a function of genotype or diet. Several blood-based amino acids and phytoestrogens were significantly altered in response to soy. Liver weight was increased in WT and adipose tissue in Fmr1KO mice fed soy. Activity levels at the beginning of the light cycle and testes weight were greater in Fmr1KO versus WT males irrespective of diet. DEXA analysis at 8-months-old indicated increased fat mass and total body area in Fmr1KO females and lean mass and bone mineral density in Fmr1KO males fed soy. Overall, dietary consumption of soy protein isolate by C57BL/6J mice caused increased growth, which could be attributed to increased lean mass in males and fat mass in females. There were sex-specific differences with more pronounced effects in Fmr1KO versus WT and in males versus females.

CRISPR/Cas9 Technology: A Novel Approach to Obesity Research

Gene editing technology, particularly Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)/CRISPR-associated protein 9 (Cas9) has transformed medical research. As a newly developed genome editing technique, CRISPR technology has strongly assisted scientists in enriching their comprehension of the roles of individual genes and their influences on a vast spectrum of human malignancies. Despite considerable progress in elucidating obesity's molecular pathways, current anti-obesity medications fall short in effectiveness. A thorough understanding of the genetic foundations underlying various neurobiological pathways related to obesity, as well as the neuro-molecular mechanisms involved, is crucial for developing effective obesity treatments. Utilizing CRISPR-based technologies enables precise determination of the roles of genes that encode transcription factors or enzymes involved in processes, such as lipogenesis, lipolysis, glucose metabolism, and lipid storage within adipose tissue. This innovative approach allows for the targeted suppression or activation of genes regulating obesity, potentially leading to effective weight management strategies. In this review, we have provided a detailed overview of obesity's molecular genetics, the fundamentals of CRISPR/Cas9 technology, and how this technology contributes to the discovery and therapeutic targeting of new genes associated with obesity.

The Increase in Childhood Obesity and Its Association with Hypertension during Pandemics

There has been a major ongoing health impact of the COVID-19 pandemic on children's lives, including lifestyle and overall health. Enforcement of prevention measures, such as school closures and social distancing, has significantly affected children's daily routines and activities. This perspective manuscript aims to explore the rise in childhood obesity and its association with hypertension during pandemics. The COVID-19 pandemic has led to significant disruptions in children's routines, including reduced physical activity, increased sedentary behavior, and changes in dietary patterns. These factors, coupled with the psychological impact of the pandemic, have contributed to an alarming increase in childhood obesity rates. This paper has highlighted the concerning increase in childhood obesity and hypertension during pandemics. The disruptions caused by the COVID-19 pandemic, including reduced physical activity, increased sedentary behaviors, and changes in dietary patterns, have contributed to the rise in these health conditions. It is crucial to recognize the long-term consequences of childhood obesity and hypertension and the urgent need for a comprehensive approach to address them.

Genetics of Obesity in Humans: A Clinical Review

Obesity is a complex multifactorial disorder with genetic and environmental factors. There is an increase in the worldwide prevalence of obesity in both developed and developing countries. The development of genome-wide association studies (GWAS) and next-generation sequencing (NGS) has increased the discovery of genetic associations and awareness of monogenic and polygenic causes of obesity. The genetics of obesity could be classified into syndromic and non-syndromic obesity. Prader-Willi, fragile X, Bardet-Biedl, Cohen, and Albright Hereditary Osteodystrophy (AHO) syndromes are examples of syndromic obesity, which are associated with developmental delay and early onset obesity. Non-syndromic obesity could be monogenic, polygenic, or chromosomal in origin. Monogenic obesity is caused by variants of single genes while polygenic obesity includes several genes with the involvement of members of gene families. New advances in genetic testing have led to the identification of obesity-related genes. Leptin (LEP), the leptin receptor (LEPR), proopiomelanocortin (POMC), prohormone convertase 1 (PCSK1), the melanocortin 4 receptor (MC4R), single-minded homolog 1 (SIM1), brain-derived neurotrophic factor (BDNF), and the neurotrophic tyrosine kinase receptor type 2 gene (NTRK2) have been reported as causative genes for obesity. NGS is now in use and emerging as a useful tool to search for candidate genes for obesity in clinical settings.

Association between Leptin (G2548A) and Leptin Receptor (Q223R) Polymorphisms with Plasma Leptin, BMI, Stress, Sleep and Eating Patterns among the Multiethnic Young Malaysian Adult Population from a Healthcare University

Relative leptin resistance in childhood to absolute leptin resistance in maturity suggests sleep, eating behaviour, and the psychological state as probable causes. The current body of research provides inconclusive evidence linking G2548A and Q223R to obesity. Furthermore, we could find very little data that have observed the association between the environment and gene polymorphism, especially in the multiethnic population that exists in Malaysia. This study searched for a possible link between sleeping habits, eating behaviour, and stress indicators with plasma leptin and its genetic variation in young adult Malaysian healthcare students. The study involved 185 first- and second-year medical and dental students from a healthcare university. Polymerase Chain Reaction−Restriction Fragment Length Polymorphism(PCR-RFLP) determined the genotype, Enzyme Linked Immunoabsorbant Assay (ELISA) tested the serum leptin, and a self-administered questionnaire evaluated sleep, eating behaviour, and psychological condition. Gender and ethnicity are linked to fasting plasma leptin levels (p < 0.001). Plasma leptin also affects stress, anxiety, and sadness. Leptin (LEP) and Leptin Receptor (LEPR) polymorphisms were not associated with BMI, plasma leptin, sleep, eating behaviour, or psychological state. Young adult Malaysian Indians were obese and overweight, while Chinese were underweight. These findings imply overweight and obese participants were in stage I of leptin resistance and lifestyle change or leptin therapy could prevent them from becoming cripplingly obese as they age.

Resting Energy Expenditure and Body Composition in Children and Adolescents With Genetic, Hypothalamic, Medication-Induced or Multifactorial Severe Obesity

Background

Pediatric obesity is a multifactorial disease which can be caused by underlying medical disorders arising from disruptions in the hypothalamic leptin-melanocortin pathway, which regulates satiety and energy expenditure.

Aim

To investigate and compare resting energy expenditure (REE) and body composition characteristics of children and adolescents with severe obesity with or without underlying medical causes.

Methods

This prospective observational study included pediatric patients who underwent an extensive diagnostic workup in our academic centre that evaluated endocrine, non-syndromic and syndromic genetic, hypothalamic, and medication-induced causes of obesity. REE was assessed by indirect calorimetry; body composition by air displacement plethysmography. The ratio between measured REE (mREE) and predicted REE (Schofield equations), REE%, was calculated, with decreased mREE defined as REE% ≤90% and elevated mREE ≥110%. Additionally, the influence of fat-free-mass (FFM) on mREE was evaluated using multiple linear regression.

Results

We included 292 patients (146 [50%] with body composition measurements), of which 218 (75%) patients had multifactorial obesity and 74 (25%) an underlying medical cause: non-syndromic and syndromic genetic (n= 29 and 28, respectively), hypothalamic (n= 10), and medication-induced (n= 7) obesity. Mean age was 10.8 ± 4.3 years, 59% were female, mean BMI SDS was 3.8 ± 1.1, indicating severe obesity. Mean REE% was higher in children with non-syndromic genetic obesity (107.4% ± 12.7) and lower in children with hypothalamic obesity (87.6% ± 14.2) compared to multifactorial obesity (100.5% ± 12.6, both p<0.01). In 9 children with pseudohypoparathyroidism type 1a, mean REE% was similar (100.4 ± 5.1). Across all patients, mREE was decreased in 60 (21%) patients and elevated in 69 (24%) patients. After adjustment for FFM, mREE did not differ between patients within each of the subgroups of underlying medical causes compared to multifactorial obesity (all p>0.05).

Conclusions

In this cohort of children with severe obesity due to various etiologies, large inter-individual differences in mREE were found. Consistent with previous studies, almost half of patients had decreased or elevated mREE. This knowledge is important for patient-tailored treatment, e.g. personalized dietary and physical activity interventions and consideration of pharmacotherapy affecting central energy expenditure regulation in children with decreased mREE.

Assessment, differential diagnosis, and initial clinical evaluation of the pediatric patient with obesity: An Obesity Medical Association (OMA) Clinical Practice Statement 2022

Background

The Obesity Medical Association (OMA) Clinical Practice Statement (CPS) on the assessment, differential diagnosis, and initial clinical evaluation of pediatric patients with obesity is intended to provide clinicians with an overview of clinical practices applicable to children and adolescents with body mass indexes greater than or equal to the 95th percentile for their ages, particularly those with adverse consequences resulting from increased body mass. The information in this CPS is based on scientific evidence, supported by the medical literature, and derived from the clinical experiences of members of the OMA.

Methods

The scientific information and clinical guidance in this CPS is based upon referenced evidence and derived from the clinical perspectives of the authors.

Results

This OMA Clinical Practice Statement on assessment, differential diagnosis, and initial clinical evaluation of pediatric patients with obesity provides clinical information regarding classification of children and adolescents with overweight or obesity, differential diagnoses to consider, and a roadmap for the initial clinical evaluation.

Conclusions

This OMA Clinical Practice Statement on assessment, differential diagnosis, and initial clinical evaluation of pediatric patients with obesity is an overview of current recommendations. Assessment of pediatric patients with obesity is the first step in determining treatments leading to the improvement of the health of children and adolescents with obesity, especially those with metabolic, physiological, and psychological complications.

High Olfactory Receptor-Rich 11q11 Copy Number in Girls and African American Children

Copy number variants (CNVs) provide numerous genetic differences between individuals, and they have been linked with multiple human diseases. Obesity is one of the highly heritable complex disorders, which is associated with copy number variance (CNV). A recent report shows that the 11q11 gene, a novel olfactory receptor, and its copy number variants are involved in the early onset of obesity. In the current study, we analyzed the 11q11 gene copy number variance (CNV) based on gender in White/European American (EA) and African American (AA) normal weight and overweight/obese children. Sixty-nine boys and fifty-eight girls between the ages of 6 and 10 years belonging to either EA or AA ethnicity were involved in this study. As per World Health Organization (WHO) guidelines, each participant’s body weight and height were recorded. DNA was extracted from saliva, and the copy number variants for the 11q11 gene were measured using digital PCR. The descriptive analysis of the 11q11 copy number showed significantly more copies in girls compared to boys; similarly, AA participants had significantly increased CNV compared to EA. The normal weight (NW) and overweight/obese (OW/OB) girls were significantly less likely to belong to the low copy number variant (LCNV) group of 11q11 compared to boys; similarly, NW and OW/OB AA children were significantly less likely to belong to the LCNV group. The AA girls in LCNV had significantly higher BMI z-scores. Our findings suggest that the 11q11 copy number in children is race and gender-specific.

All in the Family: Child and Adolescent Weight Loss Surgery in the Context of Parental Weight Loss Surgery

Background: Bariatric surgery is the most effective current treatment option for patients with severe obesity. More children and adolescents are having surgery, many whose parents have also had surgery. The current study examines whether parental surgery status moderates the association between perceived social support, emotional eating, food addiction and weight loss following surgery, with those whose parents have had surgery evidencing a stronger relationship between the psychosocial factors and weight loss as compared to their peers. Methods: Participants were 228 children and adolescents undergoing sleeve gastrectomy between 2014 and 2019 at one institution. Children and adolescents completed self-report measures of perceived family social support, emotional eating, and food addiction at their pre-surgical psychological evaluation. Change in body mass index (BMI) from pre-surgery to 3, 6, and 12 months post-surgery was assessed at follow-up clinic visits. Parents reported their surgical status as having had surgery or not. Results: There were no differences in perceived family support, emotional eating, or food addiction symptoms between those whose parents had bariatric surgery and those whose parents did not. There were some moderating effects of parent surgery status on the relationship between social support, emotional eating/food addiction, and weight loss following surgery. Specifically, at 3 months post-surgery, higher change in BMI was associated with lower perceived family support only in those whose parents had not had surgery. More pre-surgical food addiction symptoms were associated with greater weight loss at 3 months for those whose parents had not had surgery, whereas this finding was true only for those whose parents had surgery at 12 months post-surgery. Conclusions: Children and adolescents whose parents have had bariatric surgery may have unique associations of psychosocial factors and weight loss. More research is needed to determine mechanisms of these relationships.

Impact of body mass index on growth hormone stimulation tests in children and adolescents: a systematic review and meta-analysis

Peak stimulated growth hormone (GH) levels are known to decrease with increasing body mass index (BMI), possibly leading to overdiagnosis of GH deficiency (GHD) in children with overweight and obesity. However, current guidelines do not guide how to interpret the peak GH values of these children. This systematic review and meta-analysis aimed to study the effect of the BMI standard deviation score (SDS) on stimulated peak GH values in children, to identify potential moderators of this association, and to quantify the extent to which peak GH values in children with obesity are decreased. This systematic review was performed by the PRISMA guidelines. Medline, Embase, Cochrane, Web of Science, and Google Scholar databases were searched for studies reporting the impact of weight status on peak GH in children. Where possible, individual participant data was extracted and/or obtained from authors. Quality and risk of bias were evaluated using the Scottish Intercollegiate Guidelines Network (SIGN) checklists. The primary outcome was the association between peak GH values and BMI SDS. The pooled correlation coefficient r, 95% confidence interval (CI), and heterogeneity statistic I² were calculated under a multilevel, random-effects model. In addition, exploratory moderator analyses and meta-regressions were performed to investigate the effects of sex, pubertal status, presence of syndromic obesity, mean age and mean BMI SDS on the study level. For the individual participant dataset, linear mixed-models regression analysis was performed with BMI SDS as the predictor and ln(peak GH) as the outcome, accounting for the different studies and GH stimulation agents used. In total, 58 studies were included, providing data on n = 5135 children (576 with individual participant data). Thirty-six (62%) studies had high, 19 (33%) medium, and 3 (5%) low risks of bias. Across all studies, a pooled r of -0.32 (95% CI -0.41 to -0.23, n = 2434 patients from k = 29 subcohorts, I² = 75.2%) was found. In meta-regressions, larger proportions of males included were associated with weaker negative correlations (p = 0.04). Pubertal status, presence of syndromic obesity, mean age, and mean BMI SDS did not moderate the pooled r (all p > 0.05). Individual participant data analysis revealed a beta of -0.123 (95% CI -0.160 to -0.086, p < 0.0001), i.e. per one-point increase in BMI SDS, peak GH decreases by 11.6% (95% CI 8.3-14.8%). To our knowledge, this is the first systematic review and meta-analysis to investigate the impact of BMI SDS on peak GH values in children. It showed a significant negative relationship. Importantly, this relationship was already present in the normal range of BMI SDS and could lead to overdiagnosis of GHD in children with overweight and obesity. With the ever-rising prevalence of pediatric obesity, there is a need for BMI (SDS)-specific cutoff values for GH stimulation tests in children. Based on the evidence from this meta-analysis, we suggest the following weight status-adjusted cutoffs for GH stimulation tests that have cutoffs for children with normal weight of 5, 7, 10, and 20 µg/L: for overweight children: 4.6, 6.5, 9.3, and 18.6 µg/L; and for children with obesity: 4.3, 6.0, 8.6, and 17.3 µg/L.

There and Back Again: Leptin Actions in White Adipose Tissue

Leptin is a hormone discovered almost 30 years ago with important implications in metabolism. It is primarily produced by white adipose tissue (WAT) in proportion to the amount of fat. The discovery of leptin was a turning point for two principle reasons: on one hand, it generated promising expectations for the treatment of the obesity, and on the other, it changed the classical concept that white adipose tissue was simply an inert storage organ. Thus, adipocytes in WAT produce the majority of leptin and, although its primary role is the regulation of fat stores by controlling lipolysis and lipogenesis, this hormone also has implications in other physiological processes within WAT, such as apoptosis, browning and inflammation. Although a massive number of questions related to leptin actions have been answered, the necessity for further clarification facilitates constantly renewing interest in this hormone and its pathways. In this review, leptin actions in white adipose tissue will be summarized in the context of obesity.

Targeting E3 Ubiquitin Ligases and Deubiquitinases in Ciliopathy and Cancer

Cilia are antenna-like structures present in many vertebrate cells. These organelles detect extracellular cues, transduce signals into the cell, and play an essential role in ensuring correct cell proliferation, migration, and differentiation in a spatiotemporal manner. Not surprisingly, dysregulation of cilia can cause various diseases, including cancer and ciliopathies, which are complex disorders caused by mutations in genes regulating ciliary function. The structure and function of cilia are dynamically regulated through various mechanisms, among which E3 ubiquitin ligases and deubiquitinases play crucial roles. These enzymes regulate the degradation and stabilization of ciliary proteins through the ubiquitin-proteasome system. In this review, we briefly highlight the role of cilia in ciliopathy and cancer; describe the roles of E3 ubiquitin ligases and deubiquitinases in ciliogenesis, ciliopathy, and cancer; and highlight some of the E3 ubiquitin ligases and deubiquitinases that are potential therapeutic targets for these disorders.

Identifying underlying medical causes of pediatric obesity: Results of a systematic diagnostic approach in a pediatric obesity center

Background

Underlying medical causes of obesity (endocrine disorders, genetic obesity disorders, cerebral or medication-induced obesities) are thought to be rare. Even in specialized pediatric endocrinology clinics, low diagnostic yield is reported, but evidence is limited. Identifying these causes is vital for patient-tailored treatment.

Objectives

To present the results of a systematic diagnostic workup in children and adolescents referred to a specialized pediatric obesity center.

Methods

This is a prospective observational study. Prevalence of underlying medical causes was determined after a multidisciplinary, systematic diagnostic workup including growth charts analysis, extensive biochemical and hormonal assessment and genetic testing in all patients.

Results

The diagnostic workup was completed in n = 282 patients. Median age was 10.8 years (IQR 7.7–14.1); median BMI +3.7SDS (IQR +3.3-+4.3). In 54 (19%) patients, a singular underlying medical cause was identified: in 37 patients genetic obesity, in 8 patients cerebral and in 9 patients medication-induced obesities. In total, thirteen different genetic obesity disorders were diagnosed. Obesity onset <5 years (p = 0.04) and hyperphagia (p = 0.001) were indicators of underlying genetic causes, but only in patients without intellectual disability (ID). Patients with genetic obesity with ID more often had a history of neonatal feeding problems (p = 0.003) and short stature (p = 0.005). BMI-SDS was not higher in patients with genetic obesity disorders (p = 0.52). Patients with cerebral and medication-induced obesities had lower height-SDS than the rest of the cohort.

Conclusions

To our knowledge, this is the first study to report the results of a systematic diagnostic workup aimed at identifying endocrine, genetic, cerebral or medication-induced causes of pediatric obesity. We found that a variety of singular underlying causes were identified in 19% of the patients with severe childhood obesity. Because of this heterogeneity, an extensive diagnostic approach is needed to establish the underlying medical causes and to facilitate disease-specific, patient-tailored treatment.

Novel Mutations in Obesity-related Genes in Turkish Children with Non-syndromic Early Onset Severe Obesity: A Multicentre Study

OBJECTIVE

Non syndromic monogenic obesity is a rare cause of early onset severe obesity in the childhood period. This form may not be distinguishable from other forms of severe obesity without genetic analysis, particularly if patients do not exibit any physical abnormalities or developmental delay. The aim of this study was to screen 41 different obesity-related genes in children with non-syndromic early onset severe obesity.

METHODS

Children with severe (body mass index-standard deviation score >3) and early onset (<7 years) obesity were screened by next-generation sequencing based, targeted DNA custom panel for 41 known-obesity-related genes and the results were confirmed by Sanger technique.

RESULTS

Six novel variants were identified in five candidate genes in seven out of 105 children with severe obesity; two in SIM1 (p.W306C and p.Q36X), one in POMC (p.Y160H), one in PCSK1 (p.W130G fs Ter8), two in MC4R (p.D126E) and one in LEPR (p.Q4H). Additionally, two previously known variations in MC4R were identified in four patients (p.R165W in three, and p.V166I in one).

CONCLUSION

We identified six novel and four previously described variants in six obesity-related genes in 11 out of 105 childrens with early onset severe obesity. The prevalence of monogenic obesity was 10.4% in our cohort.

Identification of biomarkers for childhood obesity based on expressional correlation and functional similarity

The aim of the current study was to identify potential biomarkers of childhood obesity, and investigate molecular mechanisms and candidate agents in order to improve therapeutic strategies for childhood obesity. The GSE9624 gene expression profile was downloaded from the Gene Expression Omnibus database. The differentially expressed genes (DEGs) in omental adipose tissues were analyzed with limma package by comparing samples from obese and normal control children. Two-way hierarchical clustering was applied using the pheatmap package. The co-expression (CE) analysis was performed using online CoExpress software. Subsequent to functional classification via the GOSim package, the gene network enriched by DEGs was visualized using the Cytoscape package. The codon usage bias of the DEGs was then examined using the CAI program from the European Molecular Biology Open Software Suite. In total, 583 DEGs (273 upregulated genes and 310 downregulated genes) were observed in the omental adipose tissues between samples from obese and normal control children. Hierarchical clustering identified a significant difference between samples from obese and normal control children. Subsequent to CE analysis, 130 DEGs, which were classified into 4 clusters, were selected. The following 3 upregulated and 2 downregulated genes were identified to be significant: Upregulated genes, microtubule-associated protein tau (MAPT), destrin (actin depolymerizing factor) (DSTN) and spectrin, β, non-erythrocytic 1 (SPTBN1); downregulated genes, Rho/Rac guanine nucleotide exchange factor 2 (ARHGEF2) and spindle and kinetochore associated complex subunit 1 (SKA1). The top 3 amino acids were identified to be glycine, leucine and serine with a high bias. The DEGs MAPT, DSTN, SPTBN1, ARHGEF2 and SKA1 are suggested to be candidate biomarkers for childhood obesity.

Molecular genetics of human obesity: A comprehensive review

Obesity and its related health complications is a major problem worldwide. Hypothalamus and their signalling molecules play a critical role in the intervening and coordination with energy balance and homeostasis. Genetic factors play a crucial role in determining an individual's predisposition to the weight gain and being obese. In the past few years, several genetic variants were identified as monogenic forms of human obesity having success over common polygenic forms. In the context of molecular genetics, genome-wide association studies (GWAS) approach and their findings signified a number of genetic variants predisposing to obesity. However, the last couple of years, it has also been noticed that alterations in the environmental and epigenetic factors are one of the key causes of obesity. Hence, this review might be helpful in the current scenario of molecular genetics of human obesity, obesity-related health complications (ORHC), and energy homeostasis. Future work based on the clinical discoveries may play a role in the molecular dissection of genetic approaches to find more obesity-susceptible gene loci.

Role of Leptin Deficiency, Inefficiency, and Leptin Receptors in Obesity

Leptin protein consists of 167 amino acids, which is mainly secreted from the white adipose tissue. This protein acts on the hypothalamic regions of the brain which control eating behavior, thus playing a significant role in maintaining body's metabolism. Leptin receptors belong to glycoprotein 130 (gp130) family of cytokine receptors and exist in six isoforms (LEPR a-f), and all the isoforms are encoded by LEPR gene; out of these isoforms, the LEPR-b receptor is the 'longest form,' and in most of the cases, mutations in this isoform cause severe obesity. Also, mutations in the leptin gene (LEP) or its receptors gene can lead to obesity. Some biochemical pathways affect the bioactivity of leptin and/or its receptors. To date, eleven pathogenic mutations have been reported in the LEP which are p.L72S, p.N103K, p.R105W, p.H118L, p.S141C, p.W121X c.104_106delTCA, c.135del3bp, c.398delG, c.481_482delCT, and c.163C>T. Different mutations in the LEPR have also been reported as c.2396-1 G>T, c.1675 G>A, p.P316T, etc. In some studies, where leptin was deficient, leptin replacement therapy has shown positive impact by preventing weight gain and obesity.

Overweight and obesity in youth with developmental disabilities: a call to action

Elevated weight status has become a leading problem for adults and children around the world, regardless of the presence or lack of disability. Youth with intellectual and developmental disabilities are more vulnerable than the typical population to overweight in recent decades, and these individuals often experience overweight and obesity at higher rates than their typically developing peers. Young people with disabilities have many circumstances, beyond those of typically developing children, which increase their risk for greater body mass. These include greater medication use, having syndromes with obesity as an associated symptom, and possessing altered eating habits related to their disability. We discuss obesity-related health risks, possible weight management options, recommendations for weight maintenance or loss, and future research. Although most professionals who work with youth having developmental disabilities do not have great expertise in nutrition and weight management, we must collectively recognise the importance of weight issues for quality of life of these individuals and work with them in maintaining healthy lifestyles. Intervention options, both for caregivers and for health professionals, are discussed.

Management of obesity in children differs from that of adults

Obesity in childhood is a very common disorder with an increasing prevalence. It is one of the most serious public health challenges. The objectives of the present paper are to increase the awareness of the problem of obesity in childhood, its serious complications and the need for prevention. Overweight and obese children are likely to remain obese into adulthood and more likely to develop serious complications including health problems such as diabetes and CVD, as well as psychological and social challenges. Overweight and obesity are largely preventable. In adults it is difficult to reduce excessive weight gain once it has become established, thus children should be considered the priority population for intervention strategies and prevention. Nutrition, exercise, weight gain in infancy, genetic and environmental factors, all contribute to the aetiology. Prevention and treatment of obesity in childhood requires education and empowerment of families relating to diet and exercise, along with the regulation and control of food marketing and clear nutritional labelling. The eating and physical activity behaviour of a child is strongly influenced by environmental and social factors. Therefore treatment will have only limited success in an environment where adequate physical activity is inhibited and the consumption of high-energy food is stimulated. Government investment in a health promotion programme addressing the issue of obesity in the population as a whole, with particular emphasis on the prevention and management of obesity in childhood is vital. The family doctor and multidisciplinary team play an important role. Regular visits to the family doctor, including growth assessment, will help motivate the family to restrict energy intake and to increase exercise. Therefore the prevention of childhood obesity needs high priority.

Nutritional status and risk factors of overweight and obesity for children aged 9-15 years in Chengdu, Southwest China

Background

Obesity is widespread in the world including developing countries. However malnutrition in poor areas is still a serious problem. Few investigations, especially in a large sample, have been performed in Western area of China. This study aimed to evaluate the nutritional status of school children aged 9–15 years in large Southwest city of China, and identify the differential impact of aberrant birth categories and family history of obesity related disease on childhood overweight and obesity development.

Methods

A multistage random cluster sampling was performed to evaluate the prevalence of thinness, overweight and obesity, which were defined by the new age-, sex-, specific BMI reference developed by World Health Organization (WHO) (2007). And then a frequency matched case–control study was performed to identify the risk factors of overweight and obesity.

Results

7,194 children (3,494 boys, 3,700 girls) were recruited, and 1,282 (17.8%) had excess bodyweight (14.5% overweight, 3.3% obesity). The combined prevalence gradually decreased with age, and were more prevalent among boys than girls (P <0.05). Meanwhile 6.3% were found thinness and there were little differences in genders (P >0.05). Preterm large for gestational age (OR = 2.746), maternal history of obesity related disease (OR = 1.713), paternal history of obesity related disease (OR = 1.583), preterm appropriate for gestational age (OR = 1.564), full term small for gestational age (OR = 1.454) and full term large for gestational age (OR = 1.418) were recognized as significant risk factors in the multivariate regression analysis (P <0.05).

Conclusions

While overweight and obesity was dramatically spreading, malnutrition still remained a serious problem. This unmatched nutritional status should be emphasized in backward cities of China. Children born of both preterm and LGA, whose parents particularly mothers had a history of obesity related disease, should be emphatically intervened as early as possible.

Overweight and lifestyle among 13–15 year olds: A cross-sectional study in northern Sweden

Aim: To increase knowledge of self-rated health and lifestyle in relation to overweight/obesity among 13–15 year olds in northern Sweden. Methods: All 6768 13–15 year olds in nine out of 15 municipalities in Västerbotten County were asked to complete a cross-sectional school-based on-line survey in 2007. Eighty-two per cent participated in the study. Responses were considered reliable for 74% of the participants (2517 boys/2470 girls). The survey addressed demography, self-rated health, self-reported weight, height, and lifestyle characteristics. Simple and multiple logistic regression analyses were used. Results: Overweight/obesity (ISO body mass index ≥25 kg/m2) was more prevalent among boys (20%) than girls (11%), but more girls (19%) than boys (9%) reported fair or bad health. Overweight/obese boys and girls were more often physically inactive. For the boys, overweight/obesity was also associated with skipping breakfast, insufficient tooth brushing, and using snuff. For the girls, overweight/obesity was also associated with living with one parent and more television watching. Boys reported healthier habits concerning sleep duration, physical activity, eating breakfast, and smoking compared to the girls. On the other hand, girls reported better dietary and tooth brushing habits. Conclusions: This study uncovered two alarming findings: a fifth of the boys were overweight/obese and a fifth of the girls reported fair or bad health. Girls living with a single parent and boys and girls with unhealthy lifestyles were more likely to be overweight. Our findings emphasise the need for developing and implementing effective health promotion strategies for school-aged children to prevent an overweight and obesity epidemic that could continue into adulthood.

Weight loss after Roux-en-Y gastric bypass in obese patients heterozygous for MC4R mutations

BACKGROUND

Heterozygous mutations in melanocortin-4 receptor (MC4R) are the most frequent genetic cause of obesity. Bariatric surgery is a successful treatment for severe obesity. The mechanisms of weight loss after bariatric surgery are not well understood.

METHODS

Ninety-two patients who had Roux-en-Y gastric bypass (RYGB) surgery were screened for MC4R mutations. We compared percent excess weight loss (%EWL) in the four MC4R mutation carriers with that of two control groups: 8 matched controls and with the remaining 80 patients who underwent RYGB.

RESULTS

Four patients were heterozygous for functionally significant MC4R mutations. In patients with MC4R mutations, the %EWL after RYGB (66% EWL) was not significantly different compared to matched controls (70% EWL) and non-matched controls (60% EWL) after 1 year of follow-up.

CONCLUSIONS

This study suggests that patients with heterozygous MC4R mutations also benefit from RYGB and that weight loss may be independent of the presence of such mutations.

Psychological issues in pediatric obesity

Pediatric obesity is a major health problem and has reached epidemiological proportions today. The present paper reviews major psychological issues in pediatric obesity from a developmental perspective. Research and literature has shown that a number of developmental, family, maternal and child factors are responsible in the genesis of pediatric obesity. Family food habits, early developmental lifestyle of the child, parenting, early family relationships and harmony all contribute towards the growth and development of a child. The present review focuses on the role of developmental psychological factors in the pathogenesis of pediatric obesity and highlights the developmental factors that must be kept in mind when evaluating a case of pediatric obesity.

Leptin deficiency and leptin gene mutations in obese children from Pakistan

BACKGROUND

Congenital leptin deficiency is a rare human genetic condition clinically characterized by hyperphagia and acute weight gain usually during the first postnatal year. The worldwide data on this disorder includes only 14 cases and four pathogenic mutations have been reported in the leptin gene.

STUDY OBJECTIVE

The objectives of this study were to measure serum leptin levels in obese children and to detect leptin gene mutations in those found to be leptin deficient.

PATIENTS AND RESULTS

A total of 25 obese children were recruited for the study. Leptin deficiency was detected in nine of them. Leptin gene sequencing identified mutations in homozygous state in all the leptin deficient children. Two cases carried novel mutations (c.481_482delCT and c.104_106delTCA) and each of the remaining seven the previously reported frameshift mutation (c.398delG).

CONCLUSION

The results suggest that leptin deficiency caused by mutations in the leptin gene may frequently be seen in obese Pakistani children from Central Punjab.

Genetics of adipose tissue biology

Adipose tissue morphology and release of free fatty acids, as well as peptide hormones, are believed to contribute to obesity and related metabolic disorders. These adipose tissue phenotypes are influenced by adiposity, but there is also a strong hereditary impact. Polymorphisms in numerous adipose-expressed genes have been evaluated for association with adipocyte and clinical phenotypes. In our opinion, some results are convincing. Thus ADRB2 and GPR74 genes are associated with adipocyte lipolysis, GPR74 also with BMI; PPARG and SREBP1, which promote adipogenesis and lipid storage, are associated with T2D and possible adiposity; ADIPOQ and ARL15 are associated with circulating levels of adiponectin, ARL15 also with coronary heart disease. We anticipate that the use of complementary approaches such as expression profiling and RNAi screening, and studies of additional levels of gene regulation, that is, miRNA and epigenetics, will be important to unravel the genetics of adipose tissue function.

Genome wide association study identifies KCNMA1 contributing to human obesity

BACKGROUND

Recent genome-wide association (GWA) analyses have identified common single nucleotide polymorphisms (SNPs) that are associated with obesity. However, the reported genetic variation in obesity explains only a minor fraction of the total genetic variation expected to be present in the population. Thus many genetic variants controlling obesity remain to be identified. The aim of this study was to use GWA followed by multiple stepwise validations to identify additional genes associated with obesity.

METHODS

We performed a GWA analysis in 164 morbidly obese subjects (BMI:body mass index>40 kg/m2) and 163 Swedish subjects (>45 years) who had always been lean. The 700 SNPs displaying the strongest association with obesity in the GWA were analyzed in a second cohort comprising 460 morbidly obese subjects and 247 consistently lean Swedish adults. 23 SNPs remained significantly associated with obesity (nominal P<0.05) and were in a step-wise manner followed up in five additional cohorts from Sweden, France, and Germany together comprising 4214 obese and 5417 lean or population-based control individuals. Three samples, n=4133, were used to investigate the population-based associations with BMI. Gene expression in abdominal subcutaneous adipose tissue in relation to obesity was investigated for14 adults.

RESULTS

Potassium channel, calcium activated, large conductance, subfamily M, alpha member (KCNMA1) rs2116830*G and BDNF rs988712*G were associated with obesity in five of six investigated case-control cohorts. In meta-analysis of 4838 obese and 5827 control subjects we obtained genome-wide significant allelic association with obesity for KCNMA1 rs2116830*G with P=2.82×10(-10) and an odds ratio (OR) based on cases vs controls of 1.26 [95% C.I. 1.12-1.41] and for BDNF rs988712*G with P=5.2×10(-17) and an OR of 1.36 [95% C.I. 1.20-1.55]. KCNMA1 rs2116830*G was not associated with BMI in the population-based samples. Adipose tissue (P=0.0001) and fat cell (P=0.04) expression of KCNMA1 was increased in obesity.

CONCLUSIONS

We have identified KCNMA1 as a new susceptibility locus for obesity, and confirmed the association of the BDNF locus at the genome-wide significant level.

Prevalence and risk factors of overweight and obesity among children and adolescents with intellectual disabilities

Recent literature reviews showed that overweight and obesity represent a major health threat in adults with intellectual disability (ID). However, the current evidence around the prevalence and risk factors associated with overweight and obesity in children and adolescents with ID remains unclear. The objective of this article was thus to review the available English- and French-language studies examining the prevalence and risk factors associated with overweight and obesity in youths with ID. Ten studies providing original data on this topic were identified and included in this review. Results demonstrated that (i) overweight and obesity represent a significant secondary health problem in youths with ID; and (ii) obesity risk significantly increases with age. Considering all of the limitations of the reviewed studies (i.e. heterogeneity in sample size and in overweight and obesity classification criteria; lack of comparison group; restrictive number of risk factors examined, etc.), these findings remain preliminary and highlight the need for future research in this area.

Heritability of body weight: moving beyond genetics

Obesity is a complex disease, arising from the interaction between several genetic and environmental factors. Until recently, the genetic basis of complex diseases in general, and of obesity in particular, were poorly characterized. While the relatively rare monogenic and syndromic forms of obesity clearly recognize a genetic origin, the actual worldwide epidemics of obesity represent a challenge for the identification of the genetic factors involved, being likely the effect of several loci each having a subtle influence on the phenotypic expression. Progress in DNA analysis techniques and in computational tools, and the increasing level of characterization of the variability of the human genome has recently allowed to study comprehensively the association between genetic variants and obesity. To date, well-conducted and powered genome-wide association studies allowed to consistently identify genomic regions - lying on different chromosomes and affecting different metabolic pathways - influencing the predisposition to the accumulation of body fat, ultimately leading to overweight and obesity. However, the population attributable risk for obesity linked to the most statistically significant loci, like FTO and MC4R, remains discouragingly low, explaining only small fractions of the overall variance of body weight. In the last few years, the role of the complex interaction between genetic determinants and environmental factors in the rapid global increase of obesity has been further challenged by the entry of new players, that is the transcriptional and post-transcriptional regulation, summarized under the emerging discipline of epigenetics. The key challenge now is to move from the identification of causal genes and variants to the integration of different "omics" disciplines, finally allowing the molecular understanding of obesity and related conditions.

New directions in childhood obesity research: how a comprehensive biorepository will allow better prediction of outcomes

BACKGROUND

Childhood obesity is associated with the early development of diseases such as type 2 diabetes and cardiovascular disease. Unfortunately, to date, traditional methods of research have failed to identify effective prevention and treatment strategies, and large numbers of children and adolescents continue to be at high risk of developing weight-related disease.

AIM

To establish a unique 'biorepository' of data and biological samples from overweight and obese children, in order to investigate the complex 'gene × environment' interactions that govern disease risk.

METHODS

The 'Childhood Overweight BioRepository of Australia' collects baseline environmental, clinical and anthropometric data, alongside storage of blood samples for genetic, metabolic and hormonal profiles. Opportunities for longitudinal data collection have also been incorporated into the study design. National and international harmonization of data and sample collection will achieve required statistical power.

RESULTS

Ethical approval in the parent site has been obtained and early data indicate a high response rate among eligible participants (71%) with a high level of compliance for comprehensive data collection (range 56% to 97% for individual study components). Multi-site ethical approval is now underway.

CONCLUSIONS

In time, it is anticipated that this comprehensive approach to data collection will allow early identification of individuals most susceptible to disease, as well as facilitating refinement of prevention and treatment programs.

Prevalence of obesity among children and/or grandchildren of adult bariatric surgery patients

BACKGROUND

Clinical experience suggests that some adults who undergo bariatric surgery have children who are obese. Childhood obesity is associated with increased morbidity and mortality in later life. This study examined the prevalence of obesity among children and grandchildren (< or =12 years of age) of adult bariatric surgery patients.

METHODS

Patients in a prospective database of morbidly obese patients who underwent bariatric surgery between January 2004 and May 2007 were recruited by phone and in clinic. Patient demographics, body mass index (BMI) at surgery, and survey data were collected. The survey included questions regarding their child/grandchild's body habitus, weight, and height. Child obesity was defined as BMI percentile > or =95. Statistical significance was set at p < 0.05.

RESULTS

One hundred twenty-two patients were enrolled in this study (77% women, mean BMI 49 kg/m(2)). One hundred thirty-four out of 233 children/grandchildren identified had complete data; 41% had a BMI percentile > or =95. Only 29% of these obese children were so identified by the adult respondents. Significantly more biological children/grandchildren were obese than nonbiological (p = 0.013), and significantly more biological children were obese than biological grandchildren (p = 0.027).

CONCLUSIONS

This sample of bariatric surgery patients had a high proportion of obese preteen children/grandchildren. Obesity was most prevalent among biological children (vs. biological grandchildren and nonbiological children). Patients often did not recognize the degree of overweight in their children/grandchildren. Because families of bariatric surgery patients often include obese children, interventions aimed at all family members merit consideration.

Lessons from extreme human obesity: monogenic disorders

Human obesity has a strong genetic component. Most genes that influence an individual's predisposition to gain weight are not yet known. However, the study of extreme human obesity caused by single gene defects has provided a glimpse into the long-term regulation of body weight. These monogenic obesity disorders have confirmed that the hypothalamic leptin-melanocortin system is critical for energy balance in humans, because disruption of these pathways causes the most severe obesity phenotypes. Approximately 20 different genes and at least three different mechanisms have been implicated in monogenic causes of obesity; however, they account for fewer than 5% of all severe obesity cases. This finding suggests that the genetic basis for human obesity is likely to be extremely heterogeneous, with contributions from numerous genes acting by various, yet undiscovered, molecular mechanisms.

Obesity and vascular dysfunction

One of the most profound challenges facing public health and public health policy in Western society is the increased incidence and prevalence of both overweight and obesity. While this condition can have significant consequences for patient mortality and quality of life, it can be further exacerbated as overweight/obesity can be a powerful stimulus for the development of additional risk factors for a negative cardiovascular outcome, including increased insulin resistance, dyslipidemia and hypertension. This manuscript will present the effects of systemic obesity on broad issues of vascular function in both afflicted human populations and in the most relevant animal models. Among the topics that will be covered are alterations to vascular reactivity (both dilator and constrictor responses), adaptations in microvascular network and vessel wall structure, and alterations to the patterns of tissue/organ perfusion as a result of the progression of the obese condition. Additionally, special attention will be paid to the contribution of chronic inflammation as a contributor to alterations in vascular function, as well as the role of perivascular adipose tissue in terms of impacting vessel behavior. When taken together, it is clearly apparent that the development of the obese condition can have profound, and frequently difficult to predict, impacts on integrated vascular function. Much of this complexity appears to have its basis in the extent to which other co-morbidities associated with obesity (e.g., insulin resistance) are present and exert contributing effects.

Management approaches for pediatric obesity

Childhood obesity is a worldwide problem that has reached epidemic proportions, resulting in an increased prevalence of premature obesity-related morbidities, and, thus, probable increased health-care costs to treat children. The development of viable approaches to manage this epidemic is crucial. Most experts in the field of childhood obesity agree that the prevention of obesity in children should be the first line of management. Pediatricians must be adept at recognizing children at risk of obesity, calculating and plotting the BMI at all visits, using a change in the BMI to identify excessive weight gain, and monitoring for comorbidities associated with obesity. If obesity is present, the cornerstone of treatment is modification of dietary and exercise habits. Practice-based counseling and community-based programs that support and encourage lifestyle modifications have yielded promising short-term results. Children with severe comorbidities who are unable to achieve lifestyle modifications can be considered for either pharmacologic therapy or surgery, but these options should be considered as a last resort. Early intervention and prevention strategies are the most cost-effective methods of dealing with this issue.

Gendered dimensions of obesity in childhood and adolescence

Background

The literature on childhood and adolescent obesity is vast. In addition to producing a general overview, this paper aims to highlight gender differences or similarities, an area which has tended not to be the principal focus of this literature.

Methods

Databases were searched using the terms 'obesity' and 'child', 'adolescent', 'teenager', 'youth', 'young people', 'sex', 'gender', 'masculine', 'feminine', 'male', 'female', 'boy' and 'girl' (or variations on these terms). In order to limit the potential literature, the main focus is on other reviews, both general and relating to specific aspects of obesity.

Results

The findings of genetic studies are similar for males and females, and differences in obesity rates as defined by body mass index are generally small and inconsistent. However, differences between males and females due to biology are evident in the patterning of body fat, the fat levels at which health risks become apparent, levels of resting energy expenditure and energy requirements, ability to engage in certain physical activities and the consequences of obesity for the female reproductive system. Differences due to society or culture include food choices and dietary concerns, overall physical activity levels, body satisfaction and the long-term psychosocial consequences of childhood and adolescent obesity.

Conclusion

This review suggests differences between males and females in exposure and vulnerability to obesogenic environments, the consequences of child and adolescent obesity, and responses to interventions for the condition. A clearer focus on gender differences is required among both researchers and policy makers within this field.

Recent anthropometric trends among Swedish school children: evidence for decreasing prevalence of overweight in girls

AIM

To assess the recent prevalence of overweight and obesity in 10 year old children in Göteborg, Sweden.

METHODS

Cross-sectional data on weight and height from school health examinations, including fourth grade children, born in 1974 (n=4126), 1990 (n=4683) and 1994 (n=4193) and measured in academic years 1984/1985, 2000/2001 and 2004/2005, were used. Weight classification was based on age- and sex-specific body mass index cutoff values. The two latest cohorts were classified according to socio-economic areas.

RESULTS

Between 2000/2001 and 2004/2005, the prevalence of overweight plus obesity in girls decreased from 19.6% to 15.9% (p<0.01). Prevalence of obesity was 3.0% and 2.5% (nonsignificant), respectively. In boys, all differences between the corresponding cohorts were nonsignificant: 17.1% versus 17.6% were overweight (including obese) and 2.9% versus 2.8% were obese. In 1984/1985, prevalence of overweight plus obesity was only 8.6% among girls and 7.2% among boys, while 0.8% and 0.7% were classified as obese, respectively. The socio-economic gradient in overweight prevalence remained, particularly in girls.

CONCLUSIONS

This study suggests that the obesity epidemic in 10-11 year olds may be easing off in urban Sweden, and possibly reversing among girls. Even if future monitoring confirms these findings, much health promoting work still remains since the power of the 'obesogenic environment' will probably continue to be strong.

Insights from the genetics of severe childhood obesity

BACKGROUND

The identification and characterization of monogenic obesity syndromes have improved our understanding of the inherited component of severe obesity and have had undoubted medical benefits. This knowledge has also helped to dispel the notion that obesity represents an individual defect in behaviour with no biological basis.

CONCLUSIONS

For individuals at highest risk for complications of severe obesity, such findings provide a starting point for providing more rational mechanism-based therapies, as has successfully been achieved for congenital leptin deficiency.

Genetics of obesity

Objective

The aim was to review and update advances in genetics of obesity.

Design

Analysis and interpretation of recent investigations about regulating the energy balance as well as about gene-nutrient interactions and current nutrigenomic research methods.

Background and main statements

Obesity results from a long-term positive energy balance. However, its rising prevalence in developed and developing societies must reflect lifestyle changes, since genetic susceptibility remains stable over many generations. Like most complex diseases, obesity derives from a failure of adequate homoeostasis within the physiological system controlling body weight. The identification of genes that are involved in syndromic, monogenic and polygenic obesity has seriously improved our knowledge of body weight regulation. This disorder may arise from a deregulation at the genetic level (e.g. gene transcription or altered protein function) or environmental exposure (e.g. diet, physical activity, etc.).

Conclusions

In practice, obesity involves the interaction between genetic and environmental factors.

Obesity and polymorphisms in genes regulating human adipose tissue

Obesity is the result of an imbalance between food intake and energy expenditure resulting in the storing of energy as fat. Adipose tissue contains the largest store of energy in the body and plays important roles in regulating energy partitioning. Developments in genomics, in particular microarray-based expression profiling, have provided scientists with a number of new candidate genes whose expression in adipose tissue is regulated by obesity. Integrating expression profiles with genome-wide linkage and/or association analyses is a promising strategy to identify new genes underlying susceptibility to obesity. This article provides a comprehensive review of adipose-tissue-expressed genes implicated in predisposition to human obesity. The authors consider the following genes of particular interest: peroxisome proliferator-activated receptor gamma and, potentially, INSIG2 acting in adipogenesis; the adrenoreceptors beta 2 and 3, as well as hormone-sensitive lipase acting on lipolysis; uncoupling protein 2 acting in mitochondria energy expenditure; and among secreted molecules the cytokine tumor necrosis factor alpha and the hormone leptin. With the rapid development in genome research, we predict that additional alleles in genes regulating adipose tissue function will be established as risk factors for common obesity in the coming years. This has important implications for the prevention of obesity and may also offer new therapeutic targets.