Case report: Nerve fiber regeneration in children with melanocortin 4 receptor gene mutation related obesity treated with semaglutide.

Melanocortin 4 receptor (MC4R) mutations are the commonest cause of monogenic obesity through dysregulation of neuronal pathways in the hypothalamus and prefrontal cortex that regulate hunger and satiety. MC4R also regulates neuropathic pain pathways via JNK signaling after nerve injury. We show evidence of corneal small fiber degeneration in 2 siblings carrying a heterozygous missense variant c.508A>G, p.Ille170Val in the MC4R gene. Both children were treated with once weekly semaglutide for 6 months with no change in weight, and only a minor improvement in HbA1c and lipid profile. However, there was evidence of nerve regeneration with an increase in corneal nerve fiber density (CNFD) [child A (13.9%), child B (14.7%)], corneal nerve branch density (CNBD) [child A (110.2%), child B (58.7%)] and corneal nerve fiber length (CNFL) [child A (21.5%), child B (44.0%)].

Single-Center Experience of Using Liraglutide in Adolescents With Obesity +/- Type 2 Diabetes.

Background Childhood obesity is recognized as a chronic illness with limited therapeutic options. Tackling obesity (BMI; the weight in kilograms divided by the square of the height in meters, at the 95th percentile or higher) with lifestyle interventions, especially in adolescents, has proven to be a daunting task, yielding only modest results. Research on the use of liraglutide for weight reduction in pediatric patients has yielded conflicting results. Notably, there is a lack of studies in the Middle East reporting on the outcomes of glucagon-like peptide 1 (GLP-1) receptor agonists in treating obesity in children and adolescents, with or without diabetes. This study, conducted in the Middle East, represents the first investigation into the utilization of liraglutide for weight reduction in this pediatric population. Methods This retrospective study collected data on 22 consecutive participants, aged 12 to 19 years, who were diagnosed with obesity (defined as having a BMI greater than the 95th percentile for their age and sex) and had either type 2 diabetes mellitus (T2DM) or were non-diabetic who attended endocrine clinics in Sidra Medicine, Doha, Qatar, between 2020 and 2022. The study protocol involved a liraglutide treatment period spanning 18 months (72 weeks), with scheduled follow-up appointments at six-month intervals. The primary endpoints were changes in weight and BMI from baseline to the 72-week mark. Secondary endpoints were safety measures and changes in HbA1c.  Results Out of the initial cohort of 22 patients, 12 completed the full 72-week duration of the study, while 10 patients either discontinued treatment or did not adhere to the prescribed medication regimen due to side effects. Among the 12 patients who completed the study, six had a diagnosis of T2DM. At baseline, the weight, standard deviation score (SDS), BMI, and BMI standard deviation (SD) were 113.9 kg, 2.9, 40.9 kg/m2, and 2.6 respectively. At the 18-month follow-up, the weight, SDS, BMI, and BMI SD were 117.8kg, 2.6, 39kg/m2, and 2.5, respectively. Thus, no statistically significant change in the weight parameters was evident at 18 months compared to baseline. Dropout from the study and poor compliance were high (10 out of 22 patients) due to side effects, mainly gastrointestinal (nausea, abdominal pain, diarrhea, and vomiting). No statistically significant differences were observed between obese vs. obese with T2DM. No significant change in HbA1c was found between baseline and treatment follow-up in the diabetes patients. No adverse effects in terms of impairment of liver and kidney function or pancreatitis were observed. Conclusions The administration of liraglutide to adolescents with obesity, regardless of whether they had T2DM or not, in a real-life setting, did not yield statistically significant reductions in BMI/weight parameters, and HbA1c levels at the 72-week mark. Nevertheless, the study findings indicate that liraglutide is deemed safe for utilization within this age group, despite the presence of mild gastrointestinal side effects.

Functional Characterization of Novel MC4R Variants Identified in Two Unrelated Patients with Morbid Obesity in Qatar.

The leptin-melanocortin pathway is pivotal in appetite and energy homeostasis. Pathogenic variants in genes involved in this pathway lead to severe early-onset monogenic obesity (MO). The MC4R gene plays a central role in leptin-melanocortin signaling, and heterozygous variants in this gene are the most common cause of MO. A targeted gene panel consisting of 52 obesity-related genes was used to screen for variants associated with obesity. Variants were analyzed and filtered to identify potential disease-causing activity and validated using Sanger sequencing. We identified two novel heterozygous variants, c.253A>G p.Ser85Gly and c.802T>C p.Tyr268His, in the MC4R gene in two unrelated patients with morbid obesity and evaluated the functional impact of these variants. The impact of the variants on the MC4R gene was assessed using in silico prediction tools and molecular dynamics simulation. To further study the pathogenicity of the identified variants, GT1-7 cells were transfected with plasmid DNA encoding either wild-type or mutant MC4R variants. The effects of allelic variations in the MC4R gene on cAMP synthesis, MC4R protein level, and activation of PKA, ERB, and CREB signaling pathways in both stimulated and unstimulated ɑ-MSH paradigms were determined for their functional implications. In silico analysis suggested that the variants destabilized the MC4R structure and affected the overall dynamics of the MC4R protein, possibly leading to intracellular receptor retention. In vitro analysis of the functional impact of these variants showed a significant reduction in cell surface receptor expression and impaired extracellular ligand binding activity, leading to reduced cAMP production. Our analysis shows that the variants do not affect total protein expression; however, they are predicted to affect the post-translational localization of the MC4R protein to the cell surface and impair downstream signaling cascades such as PKA, ERK, and CREB signaling pathways. This finding might help our patients to benefit from the novel therapeutic advances for monogenic forms of obesity.

Understanding the Genetics of Early-Onset Obesity in a Cohort of Children From Qatar.

CONTEXT: Monogenic obesity is a rare form of obesity due to pathogenic variants in genes implicated in the leptin-melanocortin signaling pathway and accounts for around 5% of severe early-onset obesity. Mutations in the genes encoding the MC4R, leptin, and leptin receptor are commonly reported in various populations to cause monogenic obesity. Determining the genetic cause has important clinical benefits as novel therapeutic interventions are now available for some forms of monogenic obesity. OBJECTIVE: To unravel the genetic causes of early-onset obesity in the population of Qatar. METHODS: In total, 243 patients with early-onset obesity (above the 95% percentile) and age of onset below 10 years were screened for monogenic obesity variants using a targeted gene panel, consisting of 52 obesity-related genes. RESULTS: Thirty rare variants potentially associated with obesity were identified in 36 of 243 (14.8%) probands in 15 candidate genes (LEP, LEPR, POMC, MC3R, MC4R, MRAP2, SH2B1, BDNF, NTRK2, DYRK1B, SIM1, GNAS, ADCY3, RAI1, and BBS2). Twenty-three of the variants identified were novel to this study and the rest, 7 variants, were previously reported in literature. Variants in MC4R were the most common cause of obesity in our cohort (19%) and the c.485C>T p.T162I variant was the most frequent MC4R variant seen in 5 patients. CONCLUSION: We identified likely pathogenic/pathogenic variants that seem to explain the phenotype of around 14.8% of our cases. Variants in the MC4R gene are the commonest cause of early-onset obesity in our population. Our study represents the largest monogenic obesity cohort in the Middle East and revealed novel obesity variants in this understudied population. Functional studies will be required to elucidate the molecular mechanism of their pathogenicity.

The epidemiology, clinical, biochemical, immunological and radiological features of youth onset type 2 diabetes mellitus in the state of Qatar.

Objectives: To describe the epidemiology, clinical, biochemical, immunological and radiological aspects of youth with type 2 diabetes. Methods: Patients under 18 year of age with type 2 diabetes were recruited from 2018 to 2020, clinical data collected, autoantibodies (GAD65, IAA, IA2 and ZnT8), insulin, ALT and c-peptide were measured. Hepatic ultrasound was performed for assessment of non-alcoholic fatty liver disease (NAFLD). Results: 104 patients were identified. The incidence in 2020 and prevalence per 100,000 was 2.51 and 23.7, respectively. The age of onset was between 8.5 and 18 years with 74% of the patients being of Qatari nationality. Males were more affected than females (1.5/1). Overweight/obesity was present in 98% of all the patients, a positive family history (either both parents or a single parent) in 71% and maternal gestational diabetes mellitus (GDM) in 60% of patients. More than 90% of the patients had acanthosis nigricans. 5 patients had 1 autoantibody positivity and hepatic ultrasound detected evidence of NAFLD in majority of patients. Conclusion: Obesity, maternal GDM and family history of diabetes were the key risk factors for the development of type 2 diabetes. Autoantibody positivity may be present in youth type 2 diabetes. As youth type 2 diabetes is associated with early onset microvascular and macrovascular complications, these findings have important social and health budget implications for Qatar. Tackling the burden of maternal GDM and childhood obesity and building programmes for early detection and intervention, are therefore, essential to reduce the risk of future complications.

Case Report: Hepatic Adenomatosis in a Patient With Prader-Willi Syndrome.

Prader-Willi syndrome (PWS) is a genetic disorder caused by the lack of expression of genes on the paternally inherited chromosome region 15q11.2-q13. It is a multisystem disorder that is characterized by severe hypotonia with poor suck and feeding difficulties in early infancy, followed in early childhood by excessive eating and gradual development of morbid obesity. The incidence of type 2 diabetes mellitus is high, particularly in obese patients. Non-alcoholic fatty liver disease has also been reported in some patients with PWS. Liver adenomatosis is a benign vascular lesion of the liver, defined by the presence of >10 adenomas, in the otherwise healthy liver parenchyma. We report the first case of a patient with PWS with severe obesity, type 2 diabetes mellitus, and non-alcoholic fatty liver who also developed liver adenomatosis, review the pediatric literature on liver adenomatosis, and discuss the potential underlying mechanisms.