Cardiac function in adolescents with obesity: cardiometabolic risk factors and impact on physical fitness.

OBJECTIVE: To gain greater insights in the etiology and clinical consequences of altered cardiac function in obese adolescents. Therefore, we aimed to examine cardiac structure and function in obese adolescents, and to examine associations between altered cardiac function/structure and cardiometabolic disease risk factors or cardiopulmonary exercise capacity. METHODS: In 29 obese (BMI 31.6 ± 4.2 kg/m², age 13.4 ± 1.1 years) and 29 lean (BMI 19.5 ± 2.4 kg/m², age 14.0 ± 1.5 years) adolescents, fasted blood samples were collected to study hematology, biochemistry, liver function, glycemic control, lipid profile, and hormones, followed by a transthoracic echocardiography to assess cardiac structure/function, and a cardiopulmonary exercise test (CPET) to assess cardiopulmonary exercise parameters. Regression analyses were applied to examine relations between altered echocardiographic parameters and blood parameters or CPET parameters in the entire group. RESULTS: In obese adolescents, left ventricular septum thickness, left atrial diameter, mitral A-wave velocity, E/e' ratio were significantly elevated (p < 0.05), as opposed to lean controls, while mitral e'-wave velocity was significantly lowered (p < 0.01). Elevated homeostatic model assessment of insulin resistance and blood insulin, c-reactive protein, and uric acid concentrations (all significantly elevated in obese adolescents) were independent risk factors for an altered cardiac diastolic function (p < 0.01). An altered cardiac diastolic function was not related to exercise tolerance but to a delayed heart rate recovery (HRR; p < 0.01). CONCLUSIONS: In obese adolescents, an altered cardiac diastolic function was independently related to hyperinsulinemia and whole-body insulin resistance, and only revealed by a delayed HRR during CPET. This indicates that both hyperinsulinemia, whole-body insulin resistance, and delayed HRR could be regarded as clinically relevant outcome parameters.

Evaluation of a Role for NPY and NPY2R in the Pathogenesis of Obesity by Mutation and Copy Number Variation Analysis in Obese Children and Adolescents.

Neuropeptide Y (NPY) and its G protein-coupled NPY Y2 Receptor (NPY2R) are highly expressed in orexigenic NPY/Agouti-related peptide neurons within the arcuate nucleus, a major integrator of appetite control in the hypothalamus. As NPY and NPY2R are interesting candidate genes for obesity, we hypothesized that a genetic variation in these genes might be implicated in the pathogenesis of obesity. In the first part of this study, we performed a mutation analysis of the coding region of NPY and NPY2R with high-resolution melting curve analysis. For the highly conserved NPY gene, an extended population of 436 obese children and adolescents was screened, while for NPY2R, a smaller subset of 306 patients was used. A control population of 300 healthy individuals was screened for NPY2R to determine the general prevalence of the variants found among patients. Direct sequencing was performed for samples with melting patterns deviating from wild-type. In the second part of this study, Multiplex Amplicon Quantification (MAQ) analysis was performed in 308 obese children and adolescents to detect copy number variation (CNV) in the NPY2R region. Mutation analysis of the NPY gene led to the identification of one common missense variant (L7P; MAF 0.04), while the screening of the NPY2R gene resulted in the identification of one rare missense variant F87I in the patient population. In our CNV analysis, we could not identify copy number variation in the NPY2R region among obese children and adolescents. In summary, this study clearly indicates that genetic variation in NPY and NPY2R is at low frequency and thus does not make a major contribution to the obese phenotype in the general population.

Fear of Hypoglycemia, Parenting Stress, and Metabolic Control for Children with Type 1 Diabetes and Their Parents.

This study sets out to extend current knowledge of parenting stress and fear of hypoglycemia (FoH) in parents of children with type 1 diabetes mellitus (T1DM). We examined if the relationship between parental and children's FoH and metabolic control, as reflected by HbA1c, is mediated by parenting stress. A total of 63 parents and children with T1DM were recruited during their routine physician's appointment. Parents completed questionnaires on parenting stress and FoH. Children eight years and older also completed a questionnaire on FoH. HbA1c values were obtained from all children. Mediation analysis revealed an indirect association between parental FoH and HbA1c values through parenting stress (Sobel's z = 2.42, p = .02), but no indirect association between children's FoH and HbA1c. We concluded that parental FOH has an indirect association with the child's metabolic control that is mediated by parenting stress. More simply, fear of hypoglycemia predicts parent stress, which in turn, predicts metabolic control.

Copy number variation (CNV) analysis and mutation analysis of the 6q14.1-6q16.3 genes SIM1 and MRAP2 in Prader Willi like patients.

BACKGROUND: Prader-Willi syndrome (PWS), caused by a paternal defect on 15q11.2-q13, is the most common form of syndromic obesity. However, patients clinically diagnosed with PWS do not always show this defect on chromosome 15q and are therefore molecularly categorized as Prader Willi like (PWL). Deletions at 6q14.1-q16.3 encompassing MRAP2 and SIM1 were reported in some individuals with a PWL phenotype. In addition, a few mutations in SIM1 and MRAP2 were also previously identified in cohorts of obese individuals. Therefore, we decided to perform copy number variation analysis of the 6q14.1-6q16.3 region followed by mutation analysis of SIM1 and MRAP2 in a PWL cohort. METHODS: A genome-wide microarray analysis was performed in a group of 109 PWL patients. Next, we screened 94 PWL patients for mutations in SIM1 and MRAP2 using high-resolution melting curve analysis and Sanger sequencing. Additionally, 363 obese children and adolescents were screened for mutations in MRAP2. RESULTS: No gene harboring deletions were identified at the 6q14.1-q16.3 region in the 109 PWL patients. SIM1 mutation analysis resulted in the identification of one very rare nonsynonymous variant p.P352S (rs3734354). Another rare nonsynonymous variant, p.A40S, was detected in the MRAP2 gene. No variants were identified in the 363 obese individuals. CONCLUSIONS: In contrast to literature reports, no gene harboring deletions were identified in the SIM1 and MRAP2 regions in our PWL cohort. Secondly, taking into account their very low minor allele frequencies in public sequencing databases and the results of in silico prediction programs, further functional analysis of p.P352S found in SIM1 and p.A40S found in MRAP2 is useful. This would provide further support for a possible role of SIM1 and MRAP2 in the pathogenesis of the PWL phenotype albeit in a limited number of patients.

Nucleotide variation of sFRP5 gene is not associated with obesity in children and adolescents.

Because sFRP5 was shown to be an important extracellular modulator of the Wnt pathway, regulating adipogenesis, we wanted to investigate the role of sFRP5 variants in human, monogenic obesity by performing mutation analysis. We screened the complete sFRP5 coding region in 622 obese children and adolescents and 503 lean control individuals by high-resolution melting curve analysis and direct sequencing. We found a total of 15 sequence variants in sFRP5, 10 of which resulted in a non-synonymous amino acid change. Five of these variants were, to our knowledge, not previously reported. For one of the variants (c.-3G>A), we identified a trend towards association between the variant frequency and the obese phenotype. We argue that, when looking at conservation and location inside known protein domains, several of the identified variants (D103N, A113V, K212N and H317L), may affect sFRP5 protein function. In addition, we found c.-3G>A, residing in the Kozak sequence, with a lower frequency in cases compared to controls. However, functional studies investigating the effect of sFRP5 variants on protein function are necessary to determine the true role of sFRP5 genetic variation in human, monogenic obesity.

Genetic and structural variation in the SH2B1 gene in the Belgian population.

OBJECTIVE: Animal studies, genome-wide association and genomic structural variation studies have identified the SH2B1 gene as a candidate gene for obesity. Therefore, we have designed an extensive mutation and copy number variation (CNV) analysis investigating the prevalence of genetic and structural variations in SH2B1 in the Belgian population. DESIGN AND METHODS: In the first part of this study, we performed a mutation screen for variants in the SH2B1 coding region in 581 obese children and adolescents and 433 healthy, lean individuals with high-resolution melting curve analysis followed by direct sequencing. In the second part of this study, Multiplex Amplicon Quantification (MAQ) analysis was used to identify CNVs in the distal SH2B1-containing chr.16p11.2 region in 421 obese children and adolescents with no developmental delay or behavioral phenotype. RESULTS: Mutation analysis resulted in the identification of fifteen rare non-synonymous heterozygous variants. Several of these were found both in lean and obese subjects, suggesting that these are neutral polymorphisms. However, six private, heterozygous, non-synonymous variations were present in obese children only. Furthermore, we also identified six missense variants solely in lean individuals. CNV analysis could not identify carriers of the distal 16p11.2 deletion in our population. CONCLUSION: Our mutation analysis has demonstrated that variation in the SH2B1 gene is frequent in both lean and obese groups, with distinctive variations being present on either side of the weight spectrum. Although the equal variation frequency does not immediately support disease causality, it cannot be excluded that some variations are weight-increasing or -decreasing. Further functional testing of the variants will be necessary to fully understand the impact of these variants on SH2B1. We were not able to detect carriers of the distal 16p11.2 deletion in our study population. As we excluded patients with developmental or behavioral problems, we suggest that in addition to obesity, the distal deletion might predispose for these traits. Further characterization of the phenotype is therefore necessary to clearly identify the phenotype of the distal 16p11.2 microdeletion syndrome.

Near adult height and BMI changes in growth hormone treated short children with Noonan syndrome: the Belgian experience.

Introduction A variable near adult height (NAH) outcome after growth hormone (GH) therapy in Noonan syndrome (NS) patients with short stature has been reported. The main objective of this study was to evaluate NAH and body mass index (BMI) evolution in a large Belgian cohort of NS patients treated for short stature. The secondary objectives were to investigate whether sex, genotype, the presence of a thoracic deformity and/or a heart anomaly might affect NAH and to validate the recently developed NAH prediction model by Ranke et al. Methods Clinical and auxological data of GH treated short NS patients born before 2001 were extracted from the national Belgrow registry. NAH was available in 54 (35 male) genotyped NS using a gene panel of 9 genes, showing pathogenic variants in PTPN11 in 32 and in SOS1 in 5 patients, while in 17 patients gene panel analysis was inconclusive (no mutation group). Results After a median (P10; P90) duration of 5.4 (2.2-10.3) years of GH therapy with a median dose of 0.05 mg/kg/day NS patients reached a median NAH of -1.7 (-3.4; -0.8) SDS. Median total height gain was 1.1 (0.1; 2.3) SDS. Sex, genotype and the presence of a thoracic or cardiac malformation did not correlate with NAH or total height gain. Linear regression modelling revealed that height SDS at start (beta=0.90, p<0.001), mid-parental height SDS (beta =0.27; p=0.005), birth weight SDS (beta=0.15; p=0.051), age at start (beta=0.07; p=0032) were independently associated with NAH SDS. Median BMI SDS increased significantly (p<0.001) from -1.0 (-2.5; 0.0) at start to -0.2 (-1.5; 0.9) at NAH. The observed NAH in a subgroup of 44 patients with more than 3 years of GH treatment was not statistically different from the predicted NAH by the Noonan NAH prediction model of Ranke. Conclusion Long-term GH therapy at a dose of 0.05 mg/kg/day in short NS patients is effective in improving adult height and BMI, irrespective of the genotype and presence or absence of cardiac and or thoracic anomalies.

No important role for genetic variation in the Chibby gene in monogenic and complex obesity.

Chibby (CBY) has been identified as a potent proadipogenic factor required for adipocyte differentiation. It has been shown that CBY inhibits the canonical Wnt pathway, and therefore promotes the development of new fat cells. Our objective therefore is to investigate the contribution of rare and common genetic variation in CBY to the development of human obesity. A mutation analysis was performed on a total of 566 obese patients and 432 lean individuals. To investigate the involvement of CBY in complex obesity, we performed a genetic association analysis of the entire CBY gene region on 1,011 obese individuals and 523 control samples. Four rare, novel variants were identified in either obese patients or lean control subjects, among which two non-synonymous variations and one frameshift mutation. In addition, four previously reported CBY variants were found. In the association analysis, logistic and linear regression showed no association between common genetic variation in CBY and obesity parameters. Several novel variations were found, but no definite role in the pathogenesis of obesity could be confirmed. Results from the association analysis suggest that common variation in CBY is not a cause for obesity in the Belgian population.

Chronotropic incompetence is more frequent in obese adolescents and relates to systemic inflammation and exercise intolerance.

BACKGROUND: Adults with obesity may display disturbed cardiac chronotropic responses during cardiopulmonary exercise testing, which relates to poor cardiometabolic health and an increased risk for adverse cardiovascular events. It is unknown whether cardiac chronotropic incompetence (CI) during maximal exercise is already present in obese adolescents and, if so, how that relates to cardiometabolic health. METHODS: Sixty-nine obese adolescents (body mass index standard deviation score = 2.23 ± 0.32, age = 14.1 ± 1.2 years; mean ± SD) and 29 lean adolescents (body mass index standard deviation score = -0.16 ± 0.84, age = 14.0 ± 1.5 years) performed a maximal cardiopulmonary exercise testing from which indicators for peak performance were determined. The resting heart rate and peak heart rate were used to calculate the maximal chronotropic response index. Biochemistry (lipid profile, glycemic control, inflammation, and leptin) was studied in fasted blood samples and during an oral glucose tolerance test within obese adolescents. Regression analyses were applied to examine associations between the presence of CI and blood or exercise capacity parameters, respectively, within obese adolescents. RESULTS: CI was prevalent in 32 out of 69 obese adolescents (46%) and 3 out of 29 lean adolescents (10%). C-reactive protein was significantly higher in obese adolescents with CI compared to obese adolescents without CI (p = 0.012). Furthermore, peak oxygen uptake and peak cycling power output were significantly reduced (p < 0.05) in obese adolescents with CI vs. obese adolescents without CI. The chronotropic index was independently related to blood total cholesterol (standardized coefficient ß = -0.332; p = 0.012) and C-reactive protein concentration (standardized coefficient ß = -0.269; p = 0.039). CONCLUSION: CI is more common in the current cohort of obese adolescents, and is related to systemic inflammation and exercise intolerance.

Efficacy and safety of a 4-year combination therapy of growth hormone and gonadotropin-releasing hormone analogue in pubertal girls with short predicted adult height.

Objectives: To improve adult height in pubertal girls with a poor height prediction, treatment with growth hormone (GH) can be used in combination with a gonadotropin releasing hormone agonist (GnRHa), to delay closure of the growth plates. However, there are few studies to support this practice, and they show conflicting results. The objective of this trial is to assess the safety and efficacy of this combination treatment in early pubertal girls with a short predicted height, in comparison with matched controls. Design patients and methods: We designed an open-label, multicenter, interventional case-control study. Early pubertal girls with predicted adult height (PAH) below -2.5 SDS, were recruited in tertiary care centers in Belgium. They were treated for four years with GH and GnRHa. The girls were followed until adult height (AH) was reached. AH vs PAH, AH vs Height at start, and AH vs Target Height (TH) were evaluated, as well as safety parameters. Control data were assembled from historical patient files or from patients who preferred not to participate in the study. Results: Sixteen girls with mean age ( ± SD) at start of 11.0 years (± 1.3) completed the study protocol and follow-up. Their mean height ( ± SD) increased from 131.3 ± 4.1 cm (-2.3 ± 0.7 SDS) at start of treatment to 159.8 ± 4.7 cm (-1.1 ± 0.7 SDS) at AH. In matched controls, height increased from 132.3 ± 4.2 cm (-2.4 ± 0.5 SDS) to 153.2 ± 3.4 cm (-2.1 ± 0.6 SDS) (p<0.001). AH surpassed initial PAH by 12.0 ± 2.6 cm in treated girls; and by 4.2 ± 3.6 cm in the controls (p<0.001). Most treated girls reached normal adult height (>-2SD) (87.5%) and 68.7% reached or superseded the target height (TH), which was the case in only a minority of the controls (37.5% and 6.2%, respectively) (p= 0.003 and 0.001). A serious adverse event possibly related to the treatment, was a fracture of the metatarsals. Conclusion: A four-year GH/GnRHa treatment in early pubertal girls with a poor PAH seems safe and results in a clinically relevant and statistically significant increase in AH compared with matched historical controls. Clinical trial registration: ClinicalTrials.gov, identifier NCT00840944.

Identification of mutations in the NUCB2/nesfatin gene in children with severe obesity.

Nesfatin-1 is the N-terminal fragment of nucleobindin-2 (NUCB2) that was identified as a novel satiety molecule in rodents. The protein is reported to exert anorexigenic effects and appears to play an important role in hypothalamic pathways regulating energy homeostasis and food intake. In this study, we hypothesized that mutations in the nesfatin encoding gene NUCB2 might cause obesity in humans. Therefore, we screened the entire coding region of the NUCB2 gene for mutations in a population of 471 obese children and adolescents. Mutation analysis of NUCB2 identified a total of seven sequence variants of which four were previously reported as polymorphisms. The remaining three variants included ex9+6G>C, L125H and K178X and were found in 3 unrelated individuals in the obese population only (0.6%). Biochemical experiments including ELISA and western blot were performed on plasma samples of the obese patient carrying the nonsense mutation K178X. However, neither NUCB2/nesfatin-1 immunoreactive plasma levels of the patient, nor expression of full length NUCB2 differed significantly from matched obese control individuals. In conclusion, we have identified the first genetic variants in the NUCB2 gene in obese individuals, although further functional characterization will be essential to verify disease causality of the mutations.

Rare Heterozygous PCSK1 Variants in Human Obesity: The Contribution of the p.Y181H Variant and a Literature Review.

Recently, it was reported that heterozygous PCSK1 variants, causing partial PC1/3 deficiency, result in a significant increased risk for obesity. This effect was almost exclusively generated by the rare p.Y181H (rs145592525, GRCh38.p13 NM_000439.5:c.541T>C) variant, which affects PC1/3 maturation but not enzymatic capacity. As most of the identified individuals with the heterozygous p.Y181H variant were of Belgian origin, we performed a follow-up study in a population of 481 children and adolescents with obesity, and 486 lean individuals. We identified three obese (0.62%) and four lean (0.82%) p.Y181H carriers (p = 0.506) through sanger sequencing and high resulting melting curve analysis, indicating no association with obesity. Haplotype analysis was performed in 13 p.Y181H carriers, 20 non-carriers (10 with obesity and 10 lean), and two p.Y181H families, and showed identical haplotypes for all heterozygous carriers (p < 0.001). Likewise, state-of-the-art literature concerning the role of rare heterozygous PCSK1 variants implies them to be rarely associated with monogenic obesity, as first-degree carrier relatives of patients with PC1/3 deficiency are mostly not reported to be obese. Furthermore, recent meta-analyses have only indicated a robust association for scarce disruptive heterozygous PCSK1 variants with obesity, while clinical significance is less or sometimes lacking for most nonsynonymous variants.

Effect of nationwide reimbursement of real-time continuous glucose monitoring on HbA1c, hypoglycemia and quality of life in a pediatric type 1 diabetes population: The RESCUE-pediatrics study.

Objective: Real-time continuous glucose monitoring (RT-CGM) can improve metabolic control and quality of life (QoL), but long-term real-world data in children with type 1 diabetes (T1D) are scarce. Over a period of 24 months, we assessed the impact of RT-CGM reimbursement on glycemic control and QoL in children/adolescents with T1D treated with insulin pumps. Research design and methods: We conducted a multicenter prospective observational study. Primary endpoint was the change in HbA1c. Secondary endpoints included change in time in hypoglycemia, QoL, hospitalizations for hypoglycemia and/or ketoacidosis and absenteeism (school for children, work for parents). Results: Between December 2014 and February 2019, 75 children/adolescents were followed for 12 (n = 62) and 24 months (n = 50). Baseline HbA1c was 7.2 ± 0.7% (55 ± 8mmol/mol) compared to 7.1 ± 0.8% (54 ± 9mmol/mol) at 24 months (p = 1.0). Participants with a baseline HbA1c ≥ 7.5% (n = 27, mean 8.0 ± 0.3%; 64 ± 3mmol/mol) showed an improvement at 4 months (7.6 ± 0.7%; 60 ± 8mmol/mol; p = 0.009) and at 8 months (7.5 ± 0.6%; 58 ± 7mmol/mol; p = 0.006), but not anymore thereafter (endpoint 24 months: 7.7 ± 0.9%; 61 ± 10mmol/mol; p = 0.2). Time in hypoglycemia did not change over time. QoL for parents and children remained stable. Need for assistance by ambulance due to hypoglycemia reduced from 8 to zero times per 100 patient-years (p = 0.02) and work absenteeism for parents decreased from 411 to 214 days per 100 patient-years (p = 0.03), after 24 months. Conclusion: RT-CGM in pump-treated children/adolescents with T1D showed a temporary improvement in HbA1c in participants with a baseline HbA1c ≥ 7.5%, without increasing time in hypoglycemia. QoL was not affected. Importantly, RT-CGM reduced the need for assistance by ambulance due to hypoglycemia and reduced work absenteeism for parents after 24 months. Clinical trial registration: [ClinicalTrials.gov], identifier [NCT02601729].

Tumor spectrum in children with Noonan syndrome and SOS1 or RAF1 mutations.

Noonan syndrome (NS) is an autosomal dominant disorder caused by mutations in PTPN11, KRAS, SOS1, and RAF1. We performed SOS1, RAF1, BRAF, MEK1, and MEK2 mutation analysis in a cohort of 102 PTPN11- and KRAS-negative NS patients and found pathogenic SOS1 mutations in 10, RAF1 mutations in 4, and BRAF mutations in 2 patients. Three novel SOS1 mutations were found. One was classified as a rare benign variant and the other remains unclassified. We confirm a high prevalence of pulmonic stenosis and ectodermal abnormalities in SOS1-positive patients. Three patients with SOS1 mutations presented with tumors (embryonal rhabdomyosarcoma, Sertoli cell testis tumor, and granular cell tumors of the skin). One patient with a RAF1 mutation had a lesion suggestive for a giant cell tumor. This is the first report describing different tumor types in NS patients with germ line SOS1 mutations.

Aberrant Mechanical Efficiency during Exercise Relates to Metabolic Health and Exercise Intolerance in Adolescents with Obesity.

BACKGROUND: Mechanical efficiency (ME) might be an important parameter evaluating cardiometabolic health and the effectiveness of physical activity interventions in individuals with obesity. However, whether these cardiometabolic risk factors may relate to ME in adolescents with obesity is not known yet. Therefore, this study aims to compare the mechanical efficiency during maximal exercise testing between adolescents with obesity and lean adolescents, and to examine associations with exercise tolerance and metabolic health. METHODS: Twenty-nine adolescents with obesity (BMI SDS: 2.11 ± 0.32, age: 13.4 ± 1.1 years, male/female: 15/14) and 29 lean (BMI SDS: -0.16 ± 0.84, age: 14.0 ± 1.5 years, male/female: 16/13) adolescents performed a maximal cardiopulmonary exercise test from which the net mechanical efficiency (MEnet) and substrate oxidation (carbohydrates and lipids) were calculated. Indicators for peak performance were collected. Biochemistry (lipid profile, glycaemic control, inflammation, leptin) was studied in fasted blood samples. Regression analyses were applied to examine relations between MEnet and exercise tolerance or blood variables in the total group. RESULTS: Peak work rate (WRpeak), oxygen uptake (V˙O2peak)/WRpeak, ME, and MEnet were significantly lower (p < 0.05) in adolescents with obesity compared to their lean counterparts (p < 0.05). Furthermore, a reduced MEnet was independently related to a lower WRpeak (SC ß = 2.447; p < 0.001) and elevated carbohydrate oxidation during exercise (SC ß = -0.497; p < 0.001), as well as to elevated blood low-density lipoprotein cholesterol (SC ß = -0.275; p = 0.034) and fasting glucose (SC ß = -0.256; p = 0.049) concentration. CONCLUSION: In adolescents with obesity, the mechanical efficiency is lowered during exercise and this relates to exercise intolerance and a worse metabolic health.

Copy number variant analysis and expression profiling of the olfactory receptor-rich 11q11 region in obesity predisposition.

Genome-wide copy number surveys associated chromosome 11q11 with obesity. As this is an olfactory receptor-rich region, we hypothesize that genetic variation in olfactory receptor genes might be implicated in the pathogenesis of obesity. Multiplex Amplicon Quantification analysis was applied to screen for copy number variants at chromosome 11q11 in 627 patients with obesity and 330 healthy-weight individuals. A ± 80 kb deletion with an internally 1.3 kb retained segment was identified, covering the three olfactory receptor genes OR4C11, OR4P4, and OR4S2. A significant increase in copy number loss(es) was perceived in our patient cohort (MAF = 27%; p = 0.02). Gene expression profiling in metabolic relevant tissues was performed to evaluate the functional impact of the obesity susceptible locus. All three 11q11 genes were present in visceral and subcutaneous adipose tissue while no expression was perceived in the liver. These results support the 'metabolic system' hypothesis and imply that gene disruption of OR4C11, OR4P4, and OR4S2 will negatively influence energy metabolism, ultimately leading to fat accumulation and obesity. Our study thus demonstrates a role for structural variation within olfactory receptor-rich regions in complex diseases and defines the 11q11 deletion as a risk factor for obesity.

Comparison of flash glucose monitoring with real time continuous glucose monitoring in children and adolescents with type 1 diabetes treated with continuous subcutaneous insulin infusion.

AIMS: In 2016 intermittently scanned continuous glucose monitoring (isCGM) became the first reimbursed CGM system in Belgium. Many children with type 1 diabetes (T1D) treated with multiple daily injections as well as with continuous subcutaneous insulin infusion (CSII) switched from self-monitoring of blood glucose to isCGM to monitor their treatment. In 2017 the Enlite® real-time CGM (rtCGM) system was reimbursed enabling its use with the Minimed® 640G insulin pump with integrated SmartGuard technology. In this study we compared the metabolic control during CSII with isCGM with that during rtCGM. Patient's satisfaction and side effects of the rtCGM system were also evaluated. METHODS: 20 children with T1D, aged 5-16 years, were included. Metabolic control during the last month of isCGM use was compared to that during the 3rd and 6th month of rtCGM. RESULTS: Three patients stopped early rtCGM mainly due to calibration burden. The HbA1c level and the mean glucose value in the other patients did not change after switching to the rtCGM system. Glucose variability was smaller (46.2% vs 38.4% and 36.4%, p = 0.000). Time in hypoglycemia (<70 mg/dl) was lower (7.4% vs 1.6% and 1.5%, p = 0.000). The main patient inconvenience was the sensor calibration. CONCLUSIONS: Our data show that during Enlite® rtCGM with the Minimed® 640G pump system glucose variability was smaller and the patients spent less time in hypoglycemia than during isCGM. The need for timely calibrations is considered as the main drawback of the system.

Identification of metabolic phenotypes in childhood obesity by 1H NMR metabolomics of blood plasma.

AIM: To identify the plasma metabolic profile associated with childhood obesity and its metabolic phenotypes. MATERIALS & METHODS: The plasma metabolic profile of 65 obese and 37 normal-weight children was obtained using proton NMR spectroscopy. NMR spectra were rationally divided into 110 integration regions, which reflect relative metabolite concentrations, and were used as statistical variables. RESULTS: Obese children show increased levels of lipids, N-acetyl glycoproteins, and lactate, and decreased levels of several amino acids, α-ketoglutarate, glucose, citrate, and cholinated phospholipids as compared with normal-weight children. Metabolically healthy children show lower levels of lipids and lactate, and higher levels of several amino acids and cholinated phospholipids, as compared with unhealthy children. CONCLUSION: This study reveals new valuable findings in the field of metabolomics and childhood obesity. Although validation should be performed, the proof of principle looks promising and justifies a deeper investigation of the diagnostic possibilities of proton NMR metabolomics in follow-up studies. Trial registration: NCT03014856. Registered January 9, 2017.

Evaluation of the FreeStyle® Libre Flash Glucose Monitoring System in Children and Adolescents with Type 1 Diabetes.

BACKGROUND/AIMS: The FreeStyle® Libre Flash Glucose Monitoring System (FGM, Abbott) measures glucose concentrations in the interstitial fluid for up to 14 days. It has been approved for use in children aged > 4 years in January 2016. Experience in children is still limited. We evaluated the accuracy and usability of the FGM in children with type 1 diabetes mellitus (DM). METHODS: 67 children with type 1 DM (35 girls), aged 4-18 years, were included. Subjects wore a sensor on the back of their upper arm. For the first 14 days, they regularly measured capillary blood glucose (BG) with their usual BG meter (Accu-Chek® Mobile [ACM], Roche [n = 24]; Contour® Next Link [CNL], Bayer [n = 26]; OneTouch® Verio® IQ [OTV], LifeScan [n = 17]) followed by a sensor glucose (SG) scanning. SG readings were compared to BG measurements by consensus error grid (CEG) analysis; the mean difference (MD), the mean relative difference (MRD), the mean absolute difference (MAD), and the mean absolute relative difference (MARD) were calculated. After 14 days, subjects were asked to fill in a questionnaire on the usability of the FGM. RESULTS: 2,626 SG readings were paired with BG results. FGM readings were highly correlated with BG (r = 0.926, p < 0.001). 80.3% of the data pairs were in zone A (= no effect on clinical action) and 18.4% were in zone B (= altered clinical action with little or no effect on the clinical outcome) of the CEG. Overall MD was +7.5 mg/dL; MD varied with the BG meter: ACM +10.4 mg/dL, CNL +14.2 mg/dL, OTV -3.6 mg/dL (p < 0.001). Overall, MARD was 16.7%. We observed a large interindividual variability in the accuracy parameters. MD and MRD were inversely related to BMI (r = -0.261 [p < 0.05]; r = -0.266 [p < 0.05], respectively). MARD was inversely related to age (r = -0.266 [p < 0.05]). Twenty-nine patients (43.3%) reported sensor problems, mainly early detachment of the sensor. Nonetheless, the usability questionnaire indicated high levels of satisfaction. CONCLUSIONS: Our results showed a reasonable agreement between the FGM SG readings and capillary BG measurements in children. There was, however, a large interindividual variability. The wearing of the sensor requires special attention. Further studies in children are imperative in order to document the accuracy and safety of the FGM in the paediatric population.