Bariatric surgery in monogenic and syndromic forms of obesity

Bardet-Biedl syndrome improved diagnosis criteria and management: Inter European Reference Networks consensus statement and recommendations

Four European Reference Networks (ERN-EYE, ERKNet, Endo-ERN, ERN-ITHACA) have teamed up to establish a consensus statement and recommendations for Bardet-Biedl syndrome (BBS). BBS is an autosomal recessive ciliopathy with at least 26 genes identified to date. The clinical manifestations are pleiotropic, can be observed in utero and will progress with age. Genetic testing has progressively improved in the last years prompting for a revision of the diagnostic criteria taking into account clinical Primary and Secondary features, as well as positive or negative molecular diagnosis. This consensus statement also emphasizes on initial diagnosis, monitoring and lifelong follow-up, and symptomatic care that can be provided to patients and family members according to the involved care professionals. For paediatricians, developmental anomalies can be at the forefront for diagnosis (such as polydactyly) but can require specific care, such as for associated neuro developmental disorders. For ophthalmology, the early onset retinal degeneration requires ad hoc functional and imaging technologies and specific care for severe visual impairment. For endocrinology, among other manifestations, early onset obesity and its complications has benefited from better evaluation of eating behaviour problems, improved lifestyle programs, and from novel pharmacological therapies. Kidney and urinary track involvements warrants lifespan attention, as chronic kidney failure can occur and early management might improve outcome. This consensus recommends revised diagnostic criteria for BBS that will ensure certainty of diagnosis, giving robust grounds for genetic counselling as well as in the perspective of future trials for innovative therapies.

Rare genetic forms of obesity in childhood and adolescence: A narrative review of the main treatment options with a focus on innovative pharmacological therapies

The prevalence of obesity in children and adolescents is increasing, and it is recognised as a complex disorder that often begins in early childhood and persists throughout life. Both polygenic and monogenic obesity are influenced by a combination of genetic predisposition and environmental factors. Rare genetic obesity forms are caused by specific pathogenic variants in single genes that have a significant impact on weight regulation, particularly genes involved in the leptin-melanocortin pathway. Genetic testing is recommended for patients who exhibit rapid weight gain in infancy and show additional clinical features suggestive of monogenic obesity as an early identification allows for appropriate treatment, preventing the development of obesity-related complications, avoiding the failure of traditional treatment approaches. In the past, the primary recommendations for managing obesity in children and teenagers have been focused on making multiple lifestyle changes that address diet, physical activity, and behaviour, with the goal of maintaining these changes long-term. However, achieving substantial and lasting weight loss and improvements in body mass index (BMI) through lifestyle interventions alone is rare. Recently the progress made in genetic analysis has paved the way for innovative pharmacological treatments for different forms of genetic obesity. By understanding the molecular pathways that contribute to the development of obesity, it is now feasible to identify specific patients who can benefit from targeted treatments based on their unique genetic mechanisms.  Conclusion: However, additional preclinical research and studies in the paediatric population are required, both to develop more personalised prevention and therapeutic programs, particularly for the early implementation of innovative and beneficial management options, and to enable the translation of these novel therapy approaches into clinical practice. What is Known: • The prevalence of obesity in the paediatric population is increasing, and it is considered as a multifaceted condition that often begins in early childhood and persists in the adult life. Particularly, rare genetic forms of obesity are influenced by a combination of genetic predisposition and environmental factors and are caused by specific pathogenic variants in single genes showing a remarkable impact on weight regulation, particularly genes involved in the leptin-melanocortin pathway. • Patients who present with rapid weight gain in infancy and show additional clinical characteristics indicative of monogenic obesity should undergo genetic testing, which, by enabling a correct diagnosis, can prevent the development of obesity-related consequences through the identification for appropriate treatment. What is New: • In recent years, advances made in genetic analysis has made it possible to develop innovative pharmacological treatments for various forms of genetic obesity. In fact, it is now achievable to identify specific patients who can benefit from targeted treatments based on their unique genetic mechanisms by understanding the molecular pathways involved in the development of obesity. • As demonstrated over the last years, two drugs, setmelanotide and metreleptin, have been identified as potentially effective interventions in the treatment of certain rare forms of monogenic obesity caused by loss-of-function mutations in genes involved in the leptin-melanocortin pathway. Recent advancements have led to the development of novel treatments, including liraglutide, semaglutide and retatrutide, that have the potential to prevent the progression of metabolic abnormalities and improve the prognosis of individuals with these rare and severe forms of obesity. However, extensive preclinical research and, specifically, additional studies in the paediatric population are necessary to facilitate the translation of these innovative treatment techniques into clinical practice.

A comprehensive review of genetic causes of obesity

BACKGROUND

Obesity is a multifactorial chronic disease with a high, increasing worldwide prevalence. Genetic causes account for 7% of the cases in children with extreme obesity.

DATA SOURCES

This narrative review was conducted by searching for papers published in the PubMed/MEDLINE, Embase and SciELO databases and included 161 articles. The search used the following search terms: "obesity", "obesity and genetics", "leptin", "Prader-Willi syndrome", and "melanocortins". The types of studies included were systematic reviews, clinical trials, prospective cohort studies, cross-sectional and prospective studies, narrative reviews, and case reports.

RESULTS

The leptin-melanocortin pathway is primarily responsible for the regulation of appetite and body weight. However, several important aspects of the pathophysiology of obesity remain unknown. Genetic causes of obesity can be grouped into syndromic, monogenic, and polygenic causes and should be assessed in children with extreme obesity before the age of 5 years, hyperphagia, or a family history of extreme obesity. A microarray study, an analysis of the melanocortin type 4 receptor gene mutations and leptin levels should be performed for this purpose. There are three therapeutic levels: lifestyle modifications, pharmacological treatment, and bariatric surgery.

CONCLUSIONS

Genetic study technologies are in constant development; however, we are still far from having a personalized approach to genetic causes of obesity. A significant proportion of the affected individuals are associated with genetic causes; however, there are still barriers to its approach, as it continues to be underdiagnosed. Video Abstract (MP4 1041807 KB).

Prader–Willi Syndrome and Weight Gain Control: From Prevention to Surgery—A Narrative Review

Severe obesity remains one of the most important symptoms of Prader–Willi Syndrome (PWS), and controlling weight represents a crucial point in the therapeutical approach to the syndrome. We present an overview of different progressive patterns of growth that involve controlling weight in PWS. Mechanisms involved in the development of obesity and in preventive and therapeutic strategies to control weight gain are discussed. Early diagnosis, a controlled diet regimen, regular physical activity, follow-up by multidisciplinary teams, and hormonal treatment improved the management of excessive weight gain. In selected cases, a surgical approach can be also considered. Controlling weight in PWS remains a challenge for pediatricians. The importance of consulting different healthcare specialists, starting from the neonatal and pediatric age, is also considered as a crucial approach to controlling weight, as well as to limiting and preventing the onset of obesity and its complications.

Next-Generation Sequencing of a Large Gene Panel for Outcome Prediction of Bariatric Surgery in Patients with Severe Obesity

Obesity is a chronic disease in which abnormal deposition of fat threatens health, leading to diabetes, cardiovascular diseases, cancer, and other chronic illnesses. According to the WHO, 19.8% of the adult population in Italy is obese, and the prevalence is higher among men. It is important to know the predisposition of an individual to become obese and to respond to bariatric surgery, the most up-to-date treatment for severe obesity. To this purpose, we developed an NGS gene panel, comprising 72 diagnostic genes and 244 candidate genes, and we sequenced 247 adult obese Italian patients. Eleven deleterious variants in 9 diagnostic genes and 17 deleterious variants in 11 candidate genes were identified. Interestingly, mutations were found in several genes correlated to the Bardet-Biedl syndrome. Then, 25 patients were clinically followed to evaluate their response to bariatric surgery. After a 12-month follow-up, the patients that carried deleterious variants in diagnostic or candidate genes had a reduced weight loss, as compared to the other patients. The NGS-based panel, including diagnostic and candidate genes used in this study, could play a role in evaluating, diagnosing, and managing obese individuals, and may help in predicting the outcome of bariatric surgery.

Effects of Restrictive Bariatric Surgery on Congenital Prader-Willi Syndrome: A Case Report

Hyperphagia leading to obesity is the most common cause of mortality and morbidity in Prader-Willi syndrome (PWS). It has been classified as the most common genetic cause of the development of life-threatening obesity resulting from a defect in satiety, with an onset during early childhood. Abnormalities in the feedback from gut peptides, including ghrelin, may contribute to the satiety defect; autonomic dysfunction may also play a role in impaired satiety. Usually, pharmacological treatment is ineffective in managing obesity in these patients. A 19-year-old male child with Prader-Willi syndrome presented with morbid obesity, obstructive sleep apnea, and impaired glycemic control. The patient had complained of hyperphagia since early childhood, but food intake increased aggressively in the last few years, which resulted in morbid obesity. The patient was treated with laparoscopic sleeve gastrectomy, and the residual stomach volume was 100 ml. The intervention resulted in a 37.1% weight reduction after one year of surgery with well-controlled blood sugar levels. The patient also reported improved overall quality of life, mood, and functionality. Laparoscopic sleeve gastrectomy can be offered to obese Prader-Willi syndrome patients with heightened mortality, particularly because no other effective alternative therapy is available.

Impact of weight loss predictors in severe-morbid obesity patients in the Saudi population

Universally, obesity has been affected more than 650 million and converts as global health problem. Obesity is equally affecting starting from children to elder population. Obese subjects are converting into severe obese and then into morbid obesity. Body mass index is proning from 30 to 50 kg/m2 in the adult population. Obesity is connected with the future complications of hypertension, type 2 diabetes mellitus, cardiovascular, stroke, osteoarthritis, obstructive sleep apnea and liver diseases. Loosing of body fat is the only option to avoid obesity and this could be achieved with routine physical activity and diet modifications. Obesity subjects may fail to achieve the daily routine activities or insufficient activity may be involved and finally fail to lose the body fat after the medical course. Then these severe or morbidity obese can be lose with the existing surgery. Currently, Bariatric Surgery (BS) has become the active treatment for long-term weight loss. Various types (Roux-en-Y gastric bypass, sleeve gastrectomy and duodenal switch and the jejunoileal bypass) of BS are performed on the gastrointestinal tract. Throughout the world population, BS has found to be safe in losing the weight and avoiding the future and long-term complications. The prevalence of overweight and obesity in Saudi Arabia is an issue in terms of incidence and health consequences. Maximum obesity studies involved in Saudi Arabia has proven to be develop the long-term complications in the future involving from child to morbid obesity. Limited bariatric studies carried out in the Saudi subjects confirmed as effective tool in lowering the body fat and avoiding the life-threatened complications of human diseases. So, this review recommends BS as effective and safe surgical treatment to lose body fat in the Saudi population. However, post-operative monitoring is mandatory to follow-up.

Bariatric surgery for Prader-Willi syndrome was ineffective in producing sustainable weight loss: Long term results for up to 10 years

BACKGROUND

Obesity control in Prader-Willi syndrome (PWS) is notoriously difficult. The role of bariatric surgery in PWS remains controversial as long-term data are lacking.

OBJECTIVES

To evaluate the 10-year outcomes of bariatric surgery in PWS.

METHODS

This was a prospective observational study on PWS patients who received bariatric surgery and multidisciplinary follow-up programmes for obesity control. Outcomes on weight reduction and comorbidity resolution were evaluated.

RESULTS

Between 2008 and 2013, five PWS patients (two males, mean age 19.2 ± 3.0 years) with body mass index of 47.3 ± 6.9 kg m^-2 received sleeve gastrectomy (n = 2), one anastomosis gastric bypass (n = 2), and Roux-en-Y gastric bypass (n = 1) after failing all non-operative weight loss programmes. The median follow-up was 8.4 ± 2.2 years. The best mean percentage of total weight loss (%TWL) was achieved at 2 years (24.7%). %TWL dropped to 23.3% at 3 years, 11.9% at 5 years, 4.1% at 8 years, and 0% at 10 years. Each patient had at least three comorbidities preoperatively, but none of them had resolution of any one of the comorbidities at the last follow-up.

CONCLUSIONS

Bariatric surgery could not produce sustainable long-term weight loss or comorbidity resolution in PWS. This study suggests that bariatric surgery cannot be recommended to PWS patients as a standard treatment.

Endoscopic Sleeve Gastroplasty in 109 Consecutive Children and Adolescents With Obesity: Two-Year Outcomes of a New Modality

OBJECTIVES

Endoscopic sleeve gastroplasty (ESG) uses full-thickness sutures that restrict the stomach to a sleeve-like configuration. There is no published evidence on endoscopic tissue apposition techniques in pediatric patients. In this article, we report our ESG experience with the first 109 pediatric patients with obesity who underwent ESG under our care.

METHODS

ESG was offered as a day-case procedure under a standardized protocol and clinical pathway that included surgical, medical, and endoscopic modalities for the treatment of pediatric and adult obesity. ClinicalTrials.gov Identifier: NCT03778697.

RESULTS

The 109 patients in this study had a baseline body mass index and age of 33.0 ± 4.7 and 17.6 ± 2.2 (range: 10-21) years, respectively. Ninety-nine (90.8%) were females. The mean procedure time was 61 ± 19 minutes. The mean % total weight loss at 6, 12, 18, and 24 months was 14.4% ± 6.5%, 16.2% ± 8.3%, 15.4% ± 9.2%, and 13.7% ± 8.0%, respectively. Fourteen adolescents visited the ambulatory clinic for analgesia. One patient (aged 19.8 years) requested removal of endoscopic stitches due to abdominal pain, and another underwent Redo-ESG for insufficient weight loss. There were no blood transfusions, emergency admissions, mortality, or significant morbidity.

DISCUSSION

In this first study to date on ESG in pediatric patients, we observed that the procedure is safe and effective in children and adolescents with obesity. Significant weight loss occurs during the first 2 years without mortality or significant morbidity, and this weight loss seems to be maintained.

Laparoscopic sleeve gastrectomy in an adolescent with Prader-Willi syndrome: psychosocial implications

Prader-Willi syndrome (PWS) is a complex genetic disorder and represents the most common genetic cause of life-threatening obesity in childhood and adolescence. The indication for bariatric surgery in children and adolescents with syndromic obesity is still controversial. This case report deals with the preoperative medical and psychosocial evaluation of a 16-y-old male adolescent with PWS who underwent sleeve gastrectomy. Information on a 6-mo follow-up is also reported. The preoperative body weight was 223 kg (body mass index [BMI] 80.9 kg/m²). Comorbidities included severe obstructive sleep apnea with nocturnal respiratory failure, hypertension, and impaired glucose tolerance. At 2- and 6-mo follow-ups, the percent excess weight loss was 16 (BMI 71.8 kg/m²) and 29.2 (BMI 64.6 kg/m²), respectively. Comorbities did improve. Intellectual disability of genetic origin per se may not represent an absolute contraindication to bariatric surgery if adequate and tailored clinical and psychosocial support is provided.

Laparoscopic sleeve gastrectomy in adolescents with or without syndromic obesity: two years follow-up

INTRODUCTION

Childhood obesity is an emerging health problem. Surgical treatment of obese adolescents, particularly those affected by congenital syndrome, represents a controversial issue. The aim of this multicenter study was to retrospectively assess the results of laparoscopic sleeve gastrectomy (LSG) in a cohort of adolescents affected by morbid obesity, with or without congenital syndromes.

MATERIALS AND METHODS

Forty-one obese (BMI 49 ± 6 kg/m²) adolescents with mean age of 16 ± 3 years (58.5% with previous intragastric balloon failure), and subjected to LSG, were retrospectively evaluated for complications rate, % excess weight loss (%EWL), and inhibition of co-morbidities after 2 years of follow-up.

RESULTS

All the operations were completed laparoscopically and no intra-operative complications were recorded. No mortality was recorded while peri- or post-operative complications only occurred in two patients (4.9%). The EWL% at 6, 12, and 24 months were 42.3, 58.3, and 59.4, respectively. %EWL was comparable (p = 0.7) between non-syndromic and syndromic obese adolescents at 24 months. Conversely patients with previous intragastric balloon surgery had a significant lower EWL (%) at 24 month (p < 0.01). Moreover, at the same time point, co-morbidity resolution rate was 78.2% while improvement rate was 57.6%. Specifically, remission rate of type 2 diabetes (T2DM), hypertension and obstructive sleep apnea (OSA) were 71, 75 and 61%, respectively.

CONCLUSION

LSG is advantageous in the treatment of morbidly obese juveniles concerning safety, weight loss and co-morbidity control and at same time presenting, a possible effective therapeutic option for patients affected by congenital syndrome.

Obesity management in Prader-Willi syndrome: current perspectives

Prader-Willi syndrome (PWS) is a complex multisystem disorder due to the absent expression of the paternally active genes in the PWS critical region on chromosome 15 (15q11.2-q13). The syndrome is considered the most common genetic cause of obesity, occurring in 1:10,000-1:30,000 live births. Its main characteristics include neonatal hypotonia, poor feeding, and lack of appetite in infancy, followed by weight gain, lack of satiety, and uncontrolled appetite, frequently after the age of 2-3 years. The clinical picture includes short stature, multiple endocrine abnormalities (hypogonadism, growth hormone/insulin-like growth factor-I axis dysfunction, hypothyroidism, central adrenal insufficiency), dysmorphic features, scoliosis, osteoporosis, mental retardation, and behavioral and psychiatric problems. Subjects with PWS will become severely obese unless their food intake is strictly controlled. Constant and obsessive food seeking behavior can make life very difficult for both the family and caretakers. Prevention of obesity is mandatory in these patients from the first years of life, because once obesity develops it is difficult to maintain the control of food intake. In fact, PWS subjects die prematurely from complications conventionally related to obesity, including diabetes mellitus, metabolic syndrome, sleep apnea, respiratory insufficiency, and cardiovascular disease. The mechanisms underlying hyperphagia in PWS are not completely known, and to date no drugs have proven their efficacy in controlling appetite. Consequently, dietary restriction, physical activity, and behavior management are fundamental in the prevention and management of obesity in PWS. In spite of all available therapeutic tools, however, successful weight loss and maintenance are hardly accomplished. In this context, clinical trials with new drugs have been initiated in order to find new possibilities of a therapy for obesity in these patients. The preliminary results of these studies seem to be encouraging. On the other hand, until well-proven medical treatments are available, bariatric surgery can be taken into consideration, especially in PWS patients with life-threatening comorbidities.

Evidence Base for Multidisciplinary Care of Pediatric/Adolescent Bariatric Surgery Patients

PURPOSE OF REVIEW

Severe childhood obesity, defined as having a body mass index (BMI) greater than the 99th percentile for age and gender, is rising in most countries and is associated with early morbidity and mortality. Optimal management of the health of the child with obesity requires a multidisciplinary approach that identifies and treats associated derangements.

RECENT FINDINGS

Lifestyle interventions such as diet, exercise, and behavioral therapy for the severely obese pediatric patient are generally not effective. Few centers worldwide offer bariatric surgery for adolescents in a multidisciplinary setting, and we are the only center that offers a multidisciplinary approach that incorporates bariatric surgery for severely obese children and adolescents across all age groups. In this paper, we review up-to-date evidence in this subject including ours, and provide details on the multidisciplinary approach to pediatric obesity that accommodates bariatric surgery for children across all age groups.

Beneficial Outcomes of Sleeve Gastrectomy in a Morbidly Obese Patient With Bardet-Biedl Syndrome

Context

Severe obesity is one of the major features of Bardet-Biedl syndrome (BBS) and causes reduced life expectancy. Bariatric surgery is an effective treatment of morbid obesity. Data on the effect of bariatric surgery for monogenic obesity is essentially lacking. We present the clinical and metabolic 3-year follow-up of sleeve gastrectomy in a BBS patient.

Case Description

A 37-year-old obese woman with BBS (body mass index, 40 kg/m²) was referred to our clinic for uncontrolled diabetes, dyslipidemia, hypertension, and nonalcoholic fatty liver disease (NAFLD). After sleeve gastrectomy, progressive weight loss was observed, with a 32% total weight loss at 3-year follow-up. Glycemic control and NAFLD improved significantly. Blood pressure normalized, and treatment was discontinued 3 months after surgery.

Conclusions

Laparoscopic sleeve gastrectomy can be a safe and effective treatment of morbid BBS-related obesity in adult patients. Significant and sustained weight loss leads to the improvement of several obesity-related comorbidities such as diabetes, hypertension, and NAFLD, as in polygenic obesity. Further data are needed to confirm the long-term efficacy and safety of bariatric surgery in BBS.

Effect of interactions of polymorphisms in the Melanocortin-4 receptor gene with dietary factors on the risk of obesity and Type 2 diabetes: a systematic review

AIM

To perform a systematic review of the effect of interaction between Melanocortin-4 receptor (MC4R) single nucleotide polymorphisms and diet on the development of obesity and Type 2 diabetes.

BACKGROUND

Environmental factors, such as nutrient intakes or feeding behaviours, can modulate the association of polymorphism in the MC4R gene with obesity and Type 2 diabetes mellitus.

METHODS

A systematic literature search was conducted in the PubMed, Scopus and Google Scholar databases, with a combination of the following keywords: Diet*, nutr*, melanocortin receptor, melanocortin 4 receptor and MC4R. To assess the quality of observational studies, we used a 12-item quality checklist, derived from the STREGA statement.

RESULTS

A total of 14 articles were selected based on the inclusion and exclusion criteria. Consumption of highly salty foods and adherence to a Mediterranean dietary pattern can modulate the association between MC4R polymorphisms and the risk of obesity or Type 2 diabetes. Despite the highly contradictory results of intervention studies, after short-term lifestyle interventions, children with variant alleles of MC4R single nucleotide polymorphisms can lose more body weight, compared with non-carriers, although they may have difficulty in maintaining this weight loss in the long-term. To interpret the results of studies on adults, we need further studies.

CONCLUSIONS

The interaction between MC4R genes with dietary factors plays a significant role in the development of obesity or Type 2 diabetes phenotypes. Early detection of MC4R risk alleles in individuals and modification of their diet based on these results could be an efficient strategy to prevent obesity or diabetes in these subgroups.

Laparoscopic sleeve gastrectomy in children and adolescents with Prader-Willi syndrome: a matched-control study

BACKGROUND

Obesity is a leading cause of mortality and morbidity in Prader-Willi syndrome (PWS).

OBJECTIVES

To study weight loss and growth after laparoscopic sleeve gastrectomy (LSG) in pediatric patients with PWS compared with those without the syndrome.

SETTING

Academic center with a standardized care pathway for pediatric bariatric surgery as a part of a prospective clinical outcome study on children and adolescents undergoing weight loss surgery.

METHODS

Clinical data of all PWS patients who underwent LSG were abstracted from our prospective database, which included all pediatric patients who underwent bariatric surgery. These data were then compared with a 1:3 non-PWS group matched for age, gender, and body mass index (BMI). Data for up to 5 years follow-up were analyzed.

RESULTS

The 24 PWS patients (mean age 10.7; 6<8 yr old, range 4.9-18) had a preoperative BMI of 46.2 ± 12.2 kg/m(2). All PWS patients had obstructive sleep apnea (OSA), 62% had dyslipidemia, 43% had hypertension, and 29% had diabetes mellitus. BMI change at the first, second, third, fourth, and fifth annual visits was -14.7 (n = 22 patients), -15.0 (n = 18), 12.2 (n = 13), -12.7 (n = 11), and -10.7 (n = 7), respectively, in the PWS group, whereas the non-PWS group had a BMI change of -15.9 (n = 67), -18.0 (n = 50), -18.4 (n = 47), -18.9 (n = 26), and -19.0 (n = 20), respectively. No significant difference was observed in postoperative BMI change (P = .2-.7) or growth (postoperative height z-score P value at each annual visit = .2-.8); 95% of co-morbidities in both groups were in remission or improved, with no significant difference in the rate of co-morbidity resolution after surgery (P = .73). One PWS patient was readmitted 5 years after surgery with recurrence of OSA and heart failure. No other readmissions occurred, and there were no reoperations, postoperative leaks, or other complications. No mortality or major morbidity was observed during the 5 years of follow-up. Among the PWS patients who reached their follow-up visit time points the total follow-up rate was 94.1%, whereas in the non-PWS group it was 97%. All patients who missed a follow-up visit were subsequently seen in future follow-ups, and no patient was lost to follow-up in either group.

CONCLUSIONS

PWS children and adolescents underwent effective weight loss and resolution of co-morbidities after LSG, without mortality, significant morbidity, or slowing of growth. LSG should be offered to obese PWS patients with heightened mortality particularly because no other effective alternative therapy is available.

Rare Genetic Forms of Obesity: Clinical Approach and Current Treatments in 2016

Obesity results from a synergistic relationship between genes and the environment. The phenotypic expression of genetic factors involved in obesity is variable, allowing to distinguish several clinical pictures of obesity. Monogenic obesity is described as rare and severe early-onset obesity with abnormal feeding behavior and endocrine disorders. This is mainly due to autosomal recessive mutations in genes of the leptin-melanocortin pathway which plays a key role in the hypothalamic control of food intake. Melanocortin 4 receptor(MC4R)-linked obesity is characterized by the variable severity of obesity and no notable additional phenotypes. Mutations in the MC4R gene are involved in 2-3% of obese children and adults; the majority of these are heterozygous. Syndromic obesity is associated with mental retardation, dysmorphic features, and organ-specific developmental abnormalities. Additional genes participating in the development of hypothalamus and central nervous system have been regularly identified. But to date, not all involved genes have been identified so far. New diagnostic tools, such as whole-exome sequencing, will probably help to identify other genes. Managing these patients is challenging. Indeed, specific treatments are available only for specific types of monogenic obesity, such as leptin deficiency. Data on bariatric surgery are limited and controversial. New molecules acting on the leptin-melanocortin pathway are currently being developed.

Childhood obesity: Current and novel approaches

The prevalence of childhood obesity has increased over the last fifty years by approximately 5% per decade, and approximately a quarter of all children are now either overweight or obese. These children have a significantly increased risk of many future health problems including adult obesity, type 2 diabetes and heart disease. Despite this relentless increase, common-sense approaches aimed at prevention and treatment have failed to solve the problem. Current approaches at prevention have faced major challenges with some progress in implementing smaller scale programs and social marketing, but little action on broad public policy approaches which often appears unpalatable to society or individual governments. Meanwhile, treatment approaches have mainly focused on lifestyle change, and novel approaches are urgently needed. Prevention needs to shift to improving maternal health prior to conception, with more research focussed on the impact of early years in programming offspring to future overweight/obesity. Likewise, treatment paradigms need to move from simply thinking that obesity can be solved by readdressing diet and activity levels. Novel approaches are needed which take into consideration the complex physiology which regulates early childhood growth and the development of obesity in susceptible individuals.