Thyroid hormone levels and BMI-SDS changes in adolescents with obesity

Background

Thyroid hormones play an important role in energy metabolism and weight control, explained mostly by inducing thermogenesis and increasing basal metabolic rate. It has recently been shown that FT4 levels are associated with food preferences, which might also play a role in modulating body weight. The aim of this longitudinal follow-up study was to analyze the relationship of thyroid hormones levels (FT4, TSH) at baseline with weight/BMI-SDS changes in children and adolescents with obesity.

Methods

Three hundred seventy-seven children and adolescents have been enrolled to this study and followed up without a systematic intervention program for 5.59 ± 1.85months. Children and adolescents were divided into three subgroups: 1) 144 adolescents with obesity (15-19 years), 2) 213 children with obesity (10-14.9 years), and 3) 20 lean adolescents (15-19 years). Thyroid hormones were measured at the baseline, and anthropometry was performed at the baseline and during the follow-up. For further analyses, participants were divided according to the BMI-SDS change into two groups: 1. with BMI-SDS decrease, and 2. with BMI-SDS increase.

Results

Adolescents with obesity from the BMI-SDS decrease group had significantly lower baseline serum levels of TSH compared to the BMI-SDS increase group (2.4 ± 1.0 vs. 3.2 ± 2.0mIU/l; p=0.005). Similar difference was found for FT4 levels (14.7 ± 2.2 in the BMI-SDS decrease group vs. 15.5 ± 2.7pmol/l in the BMI-SDS increase group, p=0.048). Moreover, the BMI-SDS decrease was present in significantly higher percentage of adolescents with obesity with lower than median TSH level compared to those with higher than median TSH level at baseline (61.1% vs 38.6%, p=0.011). Likewise, the BMI-SDS decrease was present in significantly higher percentage of adolescent females with obesity and lower than median FT4 compared to those with higher than median FT4 level at baseline (70.6% vs. 23.5%, p<0.001). No associations of baseline thyroid hormones with the BMI-SDS change were observed in children with obesity or lean adolescents.

Conclusion

Adolescents with obesity and increased BMI-SDS during the follow-up had significantly higher baseline levels of both TSH and FT4 compared to BMI-SDS decrease group. These results support the previous findings that higher FT4 in individuals with obesity may influence weight gain.

Food preferences and thyroid hormones in children and adolescents with obesity

BACKGROUND

Thyroid hormones profoundly affect energy metabolism but their interrelation with food preference, which might contribute to childhood obesity development, are much less understood. In this study, we investigated if thyroid hormone levels are associated with specific modulation of food preference and potentially linked to the level of obesity in children and adolescents.

METHODS

Interrelations between food preference and peripheral thyroid activity were examined in a population of 99 non-obese and 101 obese children and adolescents (12.8 ± 3.6 years of age, 111/89 F/M) randomly selected from the patients of the Obesity and Metabolic Disease Out-patient Research Unit at National Institute for Children's Diseases in Bratislava in a period between December 2017 and March 2020.

RESULTS

Children and adolescents with obesity had a lower preference for food rich in high sucrose and high-complex carbohydrates, while the preference for protein and fat-containing food and that for dietary fibers did not differ between obese and nonobese. In adolescents with obesity, free thyroxine (FT4) correlated positively with the preference for a high protein and high fat-rich diet, irrespective of the fatty acid unsaturation level. Moreover, FT4 correlated negatively with the preference for dietary fibers, which has been also exclusively found in obese adolescents. Individuals with obesity with higher FT4 levels had higher systemic levels of AST and ALT than the population with lower FT4. Multiple regression analysis with age, sex, BMI-SDS, and FT4 as covariates revealed that FT4 and male gender are the major predictors of variability in the preference for a diet high in protein, fat, and monounsaturated fatty acids. FT4 was the sole predictor of the preference for a diet containing saturated and polyunsaturated fatty acids as well as for a diet low in fiber.

CONCLUSION

The link between free thyroxin levels and dietary preference for food rich in fat and protein is present exclusively in individuals with obesity. Higher serum FT4 was linked with elevated AST and ALT in children and adolescents with obesity, and FT4 was the best predictor for preference for food rich in fat and low in fiber. This may indicate that FT4 could contribute to the development of childhood obesity and its complications by modulating food preference.

Genetic testing is necessary for correct diagnosis and treatment in patients with isolated methylmalonic aciduria: a case report

Background

Isolated methylmalonic aciduria can be caused by pathogenic mutations in the gene for methylmalonyl-CoA mutase or in the genes encoding enzymes involved in the intracellular metabolism of cobalamin. Some of these mutations may be cobalamin responsive. The type of methylmalonic aciduria cannot always be assumed from clinical manifestation and the responsiveness to cobalamin has to be assessed for appropriate cobalamin administration, or to avoid unnecessary treatment. The cases presented herein highlight the importance of genetic testing in methylmalonic aciduria cases and the need for standardisation of the in vivo cobalamin-responsiveness assessment.

Case presentation

We describe two patients who presented in the first week of life with rapid neurological deterioration caused by metabolic acidosis with severe hyperammonaemia requiring extracorporeal elimination in addition to protein restriction, energy support, carnitine, and vitamin B12 treatment. The severity of the clinical symptoms and high methylmalonic acid concentrations in the urine (>30,000 μmol/mmol of creatinine) without hyperhomocysteinaemia in both of our patients suggested isolated methylmalonic aciduria. Based on the neonatal manifestation and the high methylmalonic acid urine levels, we assumed the cobalamin non-responsive form. The in vivo test of responsiveness to cobalamin was performed in both patients. Patient 1 was evaluated as non-responsive; thus, intensive treatment with vitamin B12 was not used. Patient 2 was responsive to cobalamin, but the dose was decreased to 1 mg i.m. every two weeks with daily oral treatment due to non-compliance. Genetic tests revealed bi-allelic mutations in the genes MMAB and MMAA in Patient 1 and 2, respectively. Based on these results, we were able to start intensive treatment with hydroxocobalamin in both patients. After the treatment intensification, there was no acute crisis requiring hospitalisation in Patient 1, and the urine methylmalonic acid levels further decreased in Patient 2.

Conclusions

Despite carrying out the in vivo test of responsiveness to cobalamin in both patients, only the results of molecular genetic tests led us to the correct diagnosis and enabled intensive treatment with hydroxocobalamin. The combination of the standardized in vivo test of cobalamin responsiveness and genetic testing is needed for accurate diagnosis and appropriate treatment of isolated methylmalonic aciduria.

Thyroid surgery in children: our experience

INTRODUCTION

Thyroid surgery in children is a rare operation. The aim of our paper is to point out the specifics of thyroid surgery in children.

METHODS

Retrospective analysis of patients hospitalized at the Department of Paediatric Surgery, Faculty of Medicine, Comenius University and National Institute of Childrens Diseases in Bratislava during a 10-year period (20072016) who underwent thyroid surgeries.

RESULTS

The retrospective analysis included 81 patients: 66 (81%) girls and 15 (19%) boys. The mean age of the patients was 14 years ±8 months (range 418 years). The most common indications for thyroid surgery were: a nodule in 36 (44.4%) patients, Graves Basedow thyrotoxicosis in 19 (23.5%) patients, and suspected thyroid carcinoma in 11 (13.6%) patients. Cervical lymph node metastases (mts) were diagnosed in 9 (11.1%) patients, and distant pulmonary metastases in 5 (6.17%) patients. Total thyroidectomy (TTE) was performed in 43 (53%) patients, total lobectomy (TL) in 20 (24.7%) patients. Extended surgery on regional lymph nodes was performed in 9 (11.1%) patients. Eight (9.9%) patients underwent reoperation. A total of 12 (14.8%) patients experienced postoperative complications. Unilateral transient recurrent laryngeal nerve (RLN) paralysis occurred in 2 patients, and permanent in one patient. Transient postoperative hypoparathyroidism with hypocalcaemia was reported in 8 (9.9%) patients; no permanent condition of this type was observed.

CONCLUSION

Multidisciplinary collaboration ensures that optimal surgical results are achieved in the patients. Experience of the surgeon performing thyroid surgery in children remains crucial.

Clinical implications of the glucokinase impaired function - GCK MODY today

Heterozygous inactivating mutations of the glucokinase (GCK) gene are causing GCK-MODY, one of the most common forms of the Maturity Onset Diabetes of the Young (MODY). GCK-MODY is characterized by fasting hyperglycemia without apparent worsening with aging and low risk for chronic vascular complications. Despite the mild clinical course, GCK-MODY could be misdiagnosed as type 1 or type 2 diabetes. In the diagnostic process, the clinical suspicion is often based on the clinical diagnostic criteria for GCK-MODY and should be confirmed by DNA analysis. However, there are several issues in the clinical and also in genetic part that could complicate the diagnostic process. Most of the people with GCK-MODY do not require any pharmacotherapy. The exception are pregnant women with a fetus which did not inherit GCK mutation from the mother. Such a child has accelerated growth, and has increased risk for diabetic foetopathy. In this situation the mother should be treated with substitutional doses of insulin. Therefore, distinguishing GCK-MODY from gestational diabetes in pregnancy is very important. For this purpose, special clinical diagnostic criteria for clinical identification of GCK-MODY in pregnancy are used. This review updates information on GCK-MODY and discusses several currently not solved problems in the clinical diagnostic process, genetics, and treatment of this type of monogenic diabetes.

[Actual trends in diagnostics and treatment of congenital hyperinsulinism]

Congenital hyperinsulinism (CHI) is the most common cause of severe persistent hypoglycemia in neonates and infants. Early diagnosis and effective treatment (based on the principles of pharmacogenetics) play the key role for the prognosis. The DNA anlysis, which can identify mutation in one of the 11 genes causing MODY, is crutial in the diagnostics. Moreover, The genotype determines also the optimal therapy approach (medicaments, diet or rarely surgery). There was a large progress of novel medicaments treating particularly most severe (diazoxide-resistant) forms of CHI.Key words: congenital hyperinsulinism - diazoxid - DNA analysis - hypoglycemia - somatostatine analogues.

Lack of association between peripheral activity of thyroid hormones and elevated TSH levels in childhood obesity

OBJECTIVE

An elevated thyroid stimulating hormone (TSH) level is a frequent finding in obese children, but its association with peripheral hormone metabolism is not fully understood. We hypothesized that in obesity, the changes in thyroid hormone metabolism in peripheral tissues might lead to dysregulation in the thyroid axis. The purpose of this study was to investigate the association of TSH with thyroid hormones in a group of obese children as compared to normal-weight controls.

METHODS

Serum TSH, free thyroxine (fT4) and free triiodothyronine (fT3) levels were measured in 101 obese children and in 40 controls. Serum reverse T3 (rT3) levels were also measured in a subgroup of 51 obese children and in 15 controls.

RESULTS

Serum TSH level was significantly higher in obese children compared to controls (2.78 vs. 1.99 mIU/L, p<0.001), while no difference was found in fT4, fT3, rT3 levels and in fT3/rT3 ratio. In the obese group, fT3 level positively correlated with fT4 (r=0.217, p=0.033) and inversely with rT3 (r=-0.288, p=0.045). However, thyroid hormone levels and TSH levels were not correlated.

CONCLUSION

In obese children, normal fT4, fT3 and rT3 levels suggest an undisturbed peripheral hormone metabolism. These levels show no correlation with elevated TSH levels.

[Genetics of monogenic forms of diabetes]

Monogenic diabetes mellitus is a type of diabetes, where genetics without any other factors is strong enough to cause the disease. According to the clinical features monogenic diabetes can be divided to the mild familial early onset diabetes, familial fasting hyperglycemia, diabetes with extrapancreatic features and neonatal diabetes mellitus. During the last several years the number of genes causing monogenic diabetes has continuously increased. The clinical picture of the monogenic diabetes is very heterogeneous, thus DNA analysis is required for identification of the diabetes etiology, which influences also the choice of treatment. This article is an overview of current knowledge on monogenic diabetes, focusing at the clinically and epidemiologically most important forms.

[Clinical and genetic aspects of monogenic obesity]

High prevalence of obesity in all of age categories is currently one of the biggest problem in medicine. Identification of etiology of obesity can individualise an approach to the patient and it is essential for choosing a target management and therapy. Beside the largest group with polygenic inheritance are clinically important also patients with "syndromic obesity", where obesity is only one of the signs and monogenic obesity, where obesity is the major clinical phenotype (patients with mutations in gene for leptin, leptine receptor, prohormone convertase 1, melanocortine receptor 4, brain-derived neurotropic factor and tyrosin kinase receptor B). The monogenic obesity includes 3-4% of all patients with obesity. This review article brings newest insight on genetics, clinical manifestation, diagnostics and therapy of these diseases.

Identification of a novel beta-cell glucokinase (GCK) promoter mutation (-71G>C) that modulates GCK gene expression through loss of allele-specific Sp1 binding causing mild fasting hyperglycemia in humans

OBJECTIVE

Inactivating mutations in glucokinase (GCK) cause mild fasting hyperglycemia. Identification of a GCK mutation has implications for treatment and prognosis; therefore, it is important to identify these individuals. A significant number of patients have a phenotype suggesting a defect in glucokinase but no abnormality of GCK. We hypothesized that the GCK beta-cell promoter region, which currently is not routinely screened, could contain pathogenic mutations; therefore, we sequenced this region in 60 such probands.

RESEARCH DESIGN AND METHODS

The beta-cell GCK promoter was sequenced in patient DNA. The effect of the identified novel mutation on GCK promoter activity was assessed using a luciferase reporter gene expression system. Electrophoretic mobility shift assays (EMSAs) were used to determine the impact of the mutation on Sp1 binding.

RESULTS

A novel -71G>C mutation was identified in a nonconserved region of the human promoter sequence in six apparently unrelated probands. Family testing established cosegregation with fasting hyperglycemia (> or = 5.5 mmol/l) in 39 affected individuals. Haplotype analysis in the U.K. family and four of the Slovakian families demonstrated that the mutation had arisen independently. The mutation maps to a potential transcriptional activator binding site for Sp1. Reporter assays demonstrated that the mutation reduces promoter activity by up to fourfold. EMSAs demonstrated a dramatic reduction in Sp1 binding to the promoter sequence corresponding to the mutant allele.

CONCLUSIONS

A novel beta-cell GCK promoter mutation was identified that significantly reduces gene expression in vitro through loss of regulation by Sp1. To ensure correct diagnosis of potential GCK-MODY (maturity-onset diabetes of the young) cases, analysis of the beta-cell GCK promoter should be included.

Coincidence of a novel KCNJ11 missense variant R365H with a paternally inherited 6q24 duplication in a patient with transient neonatal diabetes

OBJECTIVE

Neonatal diabetes is a heterogeneous group of disorders with diabetes manifestation in the first 6 months of life. The most common etiology in permanent neonatal diabetes is mutations of the ATP-sensitive K(+) channel subunits; in transient neonatal diabetes, chromosome 6q24 abnormalities are the most common cause.

RESEARCH DESIGN AND METHODS

We report a sporadic case of diabetes without ketoacidosis diagnosed on the fourth day of life.

RESULTS

Analysis of the KCNJ11 gene found a novel R365H mutation in the proband and her unaffected father. The functional analysis did not support pathogenicity of this variant. When the patient's diabetes remitted in the seventh month of life, the 6q24 region was analyzed and a paternally inherited duplication was identified.

CONCLUSIONS

Our case reports a coincidental novel KCNJ11 variant in a patient with transient neonatal diabetes due to a 6q24 duplication, illustrating the difficulty in testing neonates before the clinical course of neonatal diabetes is known.

[Mastitis in dairy cows in large-scale farming operations from the genetic aspect]

Genetic predisposition to mastitis was studied in 893 dairy cows of the Black Pied Lowland breed, daughters of 19 breeding bulls used in stocks with large-scale production technology and with loose housing, over the years 1980 to 1983. Every cow with positive bacteriological diagnosis or with a clinical manifestation of the disease was considered as suffering from mastitis. High resistance to mastitis was determined in the progeny of AO-4, EM-01, NC-17, NB-10, NEB-15, NUN-3, Nx-33 bulls, while opposite results were recorded in the progeny of NAR-45, NAR-47, NER-01, NOM-19 and REN-100 bulls. Higher milk efficiency, by 9 to 408 litres of milk was observed in positive dairy cows in the years of study. The coefficient of heritability (h2) is 0.3032. It can be concluded that the systematic control of cows from the aspect of suitability for large-scale production technology and resistance to mastitis, and evaluation of bulls according to predisposition of their daughters to this disease, is very favourable in view of the prophylaxy of bovine mastitis.

[Chromosome analysis of bulls in relation to disorders of sexual activity]

Chromosomal analysis was used for the examination of 16 bulls of different breeds from the Milhostov breeding station. The examined bulls exhibited disorders of sexual activity (disorders of spermiogenesis, aspermia, bad quality of semen, hypoplasia of testes, etc.). The examination was performed by the method after Moorhead et al. (1960) modified by Lojda et al. (1974): metaphase plates were evaluated microscopically (100 X 12) and from photos. The chromosomes were counted by means of the counting documator (from film negatives) and from photos. A card was prepared for each animal. Hyposomy (11 sires--68.75%) and hyperploidy (10 sires--62.5%) were found to be the most frequent numerical aberrations, followed by polysomy (4 sires--25.0%) and other aneuploidies (one case--6.2%). As to structural defects, breaks occurred in 14 sires (87.5%), bichromatid breaks in five sires (31.25%) and breaks on sexual chromosomes in three sires (18.75%). Centric fusion was observed in one case (6.25%), association in two cases (12.5%) and mixed aberrations in four cases (25.00%).

[Chromosome analysis of swine and their offspring with muscular weakness of the extremities]

The chromosome analysis was used to examine three triads (sire - dam - progeny) and two pairs (sire - dam) after whom the progeny inherited the muscular dystrophy of extremities. In the first case, the examination included the progeny, in the second case only the parents. The examination was performed by using lymphocyte caryotypes of peripheral blood and evaluated by the method after Moorhead et al. (1960) modified by Lojda et al. (1974). Each animal had a separate card. In all animals, hyposomy, hyperploidy and polysomy occurred most frequently, less frequent was the occurrence of breaks. With respect to the variability of the found numerical and structural changes in caryotypes of the examined animals, it was impossible to generalize the specificity of these changes for the muscular dystrophy of extremities in pigs.

[Cytogenetic study of bovine leukosis]

Nine dairy cows aged four to eleven years were subjected to examination by chromosomal analysis. These cows had been found, by haematological examination, to suffer from leucosis. The study also covered one ten-day-old calf - heifer. The test group included two dam-daughter pairs. The animals belonged to the Black-Pied Lowland breed. The blood was sampled from vena jugularis and the karyotypes were processed and evaluated by the method after Moorhead et al. (1960), modified by Lojda et al. (1974). A list was kept for each animal. The tested animals were included in classes by the percentages of the chromosome aberrations: class I - two animals (up to 10% of aberrations), class II - seven animals (from 10% to 20% of aberrations), class III - one animal (above 20% of aberrations). Hyposomy was found in all cases, polysomy and hyperploidy in four cases. Structural aberrations were observed in nine cases, breaks being the most frequent anomalies (7 cases). Breaks on sexual chromosomes were observed in five cases, including the dam-daughter pairs; centric fusion occurred in one case and mixed aberrations in two cases.

[Hereditary defects in cattle in relation to chromosome analysis]

In the cytogenetic study of karyotypes of breeding bulls and cows aimed at their health and at the hereditary defects in offspring the lymphocytes from the peripheral blood from the jugular vein were employed. On the basis of the percentual evaluation of numerical and structural deviations in karyotypes the following criteria were established: the animals with deviations up to 10%--Ist class, with deviations from 10 to 20%--IInd class, with deviations over 20%--IIIrd class. From 17 breeding bulls of the first group two were included in the Ist class, twelve in the IInd class and three in the IIIrd class. From the second group, two sires belonged to the IInd class and four to the IIIrd class. Both dairy cows (mothers) that delivered calves with lethal factors, as well as the leukosis-suffering mother with daughter, were included in the IIIrd class. The chromosome analyses are given in tables.

[Cytogenetic analysis of lymphoid blood cells in bovine leucosis]

For the cytogenetic analysis lymphocytes of the peripheral blood were used that had been obtained from cows suffering from leucosis. The blood was taken from a diseased cow, from its 15 months old daughter suffering from leucosis, and from the healthy bull-father (NAT-47). The diagnosis of leucosis was determined by means of hematological examination. In the cow 139 metaphase plates were evaluated, in the daughter 118, and in the bull 132. On the one hand, normoploidy was determined and on the other hand, chromosome aberrations. In the cow 31.0 p. c. of chromosome aberrations were found, in the daughter 32.3 p. c., and in the bull 37.2 p. c. Breaks in X chromosomes were found in the cow (6.7 p. c.) and in the daughter (1.7 p. c.). Longitudinal diversion of arms in the centromere in X chromosomes in the vertical axis into two separate arms was found in the cow amounting to 6.5 p. c., in the daughter to 5.9 p. c., and in the bull to only 0.8 p. c.