Determination of Optimal Vitamin D Dosage in Children with Cholestasis.

BACKGROUND: Vitamin D deficiency in patients with cholestasis is due to impaired intestinal vitamin D absorption, which results from decreased intestinal bile acid concentration. Patients with cholestasis usually do not achieve optimal vitamin D status when a treatment regimen for children without cholestasis is used. However, data on high-dose vitamin D treatment in patients with cholestasis are limited. METHODS: This study is a prospective study that included pediatric patients with cholestasis (serum direct bilirubin > 1 mg/dL) who had vitamin D deficiency (serum 25-hydroxyvitamin D, 25-OHD, < 20 ng/mL). In Phase 1, single-day oral loading of 300,000 IU (or 600,000 IU if weight ≥ 20 kg) of vitamin D2 was administered, followed by an additional loading if serum 25-OHD < 30 ng/mL, and 4-week continuation of treatment using a vitamin D2 dose calculated based on the increment of 25-OHD after first loading. In Phase 2, oral vitamin D2 (200,000 IU/day) was administered for 12 days, followed by 400,000 IU/day of vitamin D2 orally for another 8 weeks if serum 25-OHD < 30 ng/mL. RESULTS: Phase 1: Seven patients were enrolled. Three out of seven patients had a moderate increase in serum 25-OHD after loading (up to 20.3-27.2 ng/mL). These patients had conditions with partially preserved bile flow. The remaining four patients, who had biliary atresia with failed or no Kasai operation, had low increments of serum 25-OHD. Phase 2: Eleven patients were enrolled. Eight out of 11 patients had a moderate increase in serum 25-OHD after 200,000 IU/day of vitamin D2 for 12 days. Serum 25-OHD continued increasing after administering 400,000 IU/day of vitamin D2 for another 8 weeks, with maximal serum 25-OHD of 15.7-22.8 ng/mL. CONCLUSION: Very high doses of vitamin D2 (200,000 and 400,000 IU/day) partly overcame poor intestinal vitamin D absorption and resulted in moderate increases in serum 25-OHD in pediatric patients with cholestasis, particularly when cholestasis was caused by uncorrectable bile duct obstruction.

Young-onset diabetes patients in Thailand: Data from Thai Type 1 Diabetes and Diabetes diagnosed Age before 30 years Registry, Care and Network (T1DDAR CN).

AIMS/INTRODUCTION: There is a lack of current information regarding young-onset diabetes in Thailand. Thus, the objectives of this study were to describe the types of diabetes, the clinical characteristics, the treatment regimens and achievement of glycemic control in Thai patients with young-onset diabetes. MATERIALS AND METHODS: Data of 2,844 patients with diabetes onset before 30 years-of-age were retrospectively reviewed from a diabetes registry comprising 31 hospitals in Thailand. Gestational diabetes was excluded. RESULTS: Based on clinical criteria, type 1 diabetes was identified in 62.6% of patients, type 2 diabetes in 30.7%, neonatal diabetes in 0.8%, other monogenic diabetes in 1.7%, secondary diabetes in 3.0%, genetic syndromes associated with diabetes in 0.9% and other types of diabetes in 0.4%. Type 1 diabetes accounted for 72.3% of patients with age of onset <20 years. The proportion of type 2 diabetes was 61.0% of patients with age of onset from 20 to <30 years. Intensive insulin treatment was prescribed to 55.2% of type 1 diabetes patients. Oral antidiabetic agent alone was used in 50.8% of type 2 diabetes patients, whereas 44.1% received insulin treatment. Most monogenic diabetes, secondary diabetes and genetic syndromes associated with diabetes required insulin treatment. Achievement of glycemic control was identified in 12.4% of type 1 diabetes patients, 30% of type 2 diabetes patients, 36.4% of neonatal diabetes patients, 28.3% of other monogenic diabetes patients, 45.6% of secondary diabetes patients and 28% of genetic syndromes associated with diabetes patients. CONCLUSION: In this registry, type 1 diabetes remains the most common type and the prevalence of type 2 diabetes increases with age. The majority of patients did not achieve the glycemic target, especially type 1 diabetes patients.

Type 1 diabetes management and outcomes: A multicenter study in Thailand.

AIMS/INTRODUCTION: The Thai Type 1 Diabetes and Diabetes Diagnosed Before Age 30 Years Registry, Care and Network was established in 2014 and involved 31 hospitals. The objective of the registry was to evaluate glycemic control and complications of patients with type 1 diabetes. MATERIALS AND METHODS: Patients' demographics, clinical data, frequencies of daily self-monitoring of blood glucose (SMBG), glycemic control and complications were collected. RESULTS: Among the 1,907 type 1 diabetes patients, the mean age was 21.2 ± 11.3 years. The mean glycated hemoglobin level was 9.35 ± 2.41%, with significant variations among age groups (P < 0.001). Conventional insulin treatment and intensive insulin treatment were used in 43 and 57% of patients, respectively. Mean glycated hemoglobin levels were significantly higher in patients treated with conventional insulin treatment compared to those treated with intensive insulin treatment (9.63 ± 2.34 vs 9.17 ± 2.46%, P = 0.002). Compared to the conventional insulin treatment group, significantly more patients in the intensive insulin treatment group achieved good glycemic control (P < 0.001), and fewer had diabetic retinopathy (P = 0.031). The prevalence of microvascular complications increased significantly with age (P < 0.001). Multivariate analysis showed good glycemic control to be associated with age 25 to <45 years, intensive insulin treatment with SMBG three or more times daily and diabetes duration of 1 to <5 years. CONCLUSIONS: Most Thai type 1 diabetes patients were not meeting the recommended glycemic target. As a result of this study, the national program to improve the quality of diabetes treatment and education has been implemented, and the results are ongoing.

DUOX2 variants are a frequent cause of congenital primary hypothyroidism in Thai patients.

OBJECTIVE: To identify the genetic etiologies of congenital primary hypothyroidism (CH) in Thai patients. DESIGN AND METHODS: CH patients were enrolled. Clinical characteristics including age, signs and symptoms of CH, pedigree, family history, screened thyroid-stimulating hormone results, thyroid function tests, thyroid imaging, clinical course and treatment of CH were collected. Clinical exome sequencing by next-generation sequencing was performed. In-house gene list which covered 62 potential candidate genes related to CH and thyroid disorders was developed for targeted sequencing. Sanger sequencing was performed to validate the candidate variants. Thyroid function tests were determined in the heterozygous parents who carried the same DUOX2 or DUOXA2 variants as their offsprings. RESULTS: There were 118 patients (63 males) included. Mean (SD) age at enrollment was 12.4 (7.9) years. Forty-five of 118 patients (38%) had disease-causing variants. Of 45 variants, 7 genes were involved (DUOX2, DUOXA2, TG, TPO, SLC5A5, PAX8 and TSHR). DUOX2, a gene causing thyroid dyshormonogenesis, was the most common defective gene (25/45, 56%). The most common DUOX2 variant found in this study was c.1588A>T. TG and TPO variants were less common. Fourteen novel variants were found. Thyroid function tests of most parents with heterozygous state of DUOX2 and DUOXA2 variants were normal. CONCLUSIONS: DUOX2 variants were most common among Thai CH patients, while TG and TPO variants were less common. The c.1588A>T in DUOX2 gene was highly frequent in this population.

Clinical and Molecular Analysis in 2 Families With Novel Compound Heterozygous SBP2 (SECISBP2) Mutations.

CONTEXT: Selenocysteine insertion sequence binding protein 2 (SECISBP2, SBP2) is an essential factor for selenoprotein synthesis. Individuals with SBP2 defects have characteristic thyroid function test (TFT) abnormalities resulting from deficiencies in the selenoenzymes deiodinases. Eight families with recessive SBP2 gene mutations have been reported to date. We report 2 families with inherited defect in thyroid hormone metabolism caused by 4 novel compound heterozygous mutations in the SBP2 gene. CASE DESCRIPTIONS: Probands 1 and 2 presented with growth and developmental delay. Both had characteristic TFT with high T4, low T3, high reverse T3, and normal or slightly elevated TSH. The coding region of the SBP2 gene was sequenced and analysis of in vitro translated wild-type and mutant SBP2 proteins was performed. Sequencing of the SBP2 gene identified novel compound heterozygous mutations resulting in mutant SBP2 proteins E679D and R197* in proband 1, and K682Tfs*2 and Q782* in proband 2. In vitro translation of the missense E679D demonstrated all four isoforms, whereas R197* had only 2 shorter isoforms translated from downstream ATGs, and Q782*, K682Tfs*2 expressed isoforms with truncated C-terminus. Reduction in serum glutathione peroxidase enzymatic activity was also demonstrated in both probands. CONCLUSIONS: We report 2 additional families with mutations in the SBP2 gene, a rare inherited condition manifesting global selenoprotein deficiencies. Report of additional families with SBP2 deficiency and their evaluation over time is needed to determine the full spectrum of clinical manifestations in SBP2 deficiency and increase our understanding of the role played by SBP2 and selenoproteins in health and disease.

Role of the Thyroid Gland in Expression of the Thyroid Phenotype of Sbp2-Deficient Mice.

Selenocysteine insertion sequence-binding protein 2, SBP2 (SECISBP2), is required for selenoprotein synthesis. Partial SBP2 deficiency syndrome manifests characteristic thyroid function tests. The Sbp2 deficiency mouse model, Sbp2 inducible conditional knockout (iCKO), replicates this thyroid phenotype and was used for pathophysiologic investigations. As selenoproteins have an antioxidative role in thyroid gland function, their deficiencies have potential to affect thyroid hormone (TH) synthesis. Sbp2 iCKO mice had larger thyroids relative to body weight and increased thyroidal thyroxine (T4) and triiodothyronine (T3) content while 5' deiodinases enzymatic activities were decreased. Possible mechanisms for the discrepancy between the increased thyroidal T3 and normal circulating T3 were investigated in dynamic experiments. Treatment with bovine thyroid-stimulating hormone (TSH) resulted in increased delta T4 in Sbp2 iCKO mice, indicating increased availability of preformed thyroidal TH. Next, the recovery of TH levels was evaluated after withdrawal of chemical suppression. At one day, Sbp2 iCKO mice had higher serum and thyroidal T3 concomitant with lower TSH, confirming increased capacity of TH synthesis in Sbp2 deficiency. Decreased TH secretion was ruled out as serum and thyroidal TH were high in Sbp2 iCKO mice. Treatment with a low-iodine diet also ruled out thyroidal secretion defect as both serum levels and thyroidal TH content similarly declined over time in Sbp2-deficient mice compared to wild-type (Wt) mice. This study provides evidence for unsuspected changes in the thyroid gland that contribute to the thyroid phenotype of Sbp2 deficiency, with increased thyroidal T4 and T3 content in the setting of increased TH synthesis capacity contributing to the circulating TH levels while thyroidal secretion is preserved.

Sorting Variants of Unknown Significance Identified by Whole Exome Sequencing: Genetic and Laboratory Investigations of Two Novel MCT8 Variants.

Mutations in the cell membrane thyroid hormone (TH) transporter monocarboxylate transporter (MCT) 8 produce severe neuropsychomotor defects and characteristic thyroid function test (TFT) abnormalities. Two children with mild neurological phenotypes and normal TFTs were found to harbor MCT8 gene variants of unknown significance (VUS), MCT8-R388Q that occurred de novo, and MCT8-Q212E. Normal TH transport and action in fibroblasts of MCT8-R388Q was demonstrated in a novel nonradioactive functional assay measuring the intracellular TH availability after L-T3 treatment. No genotype-phenotype correlation was found in additional family members carrying MCT8-Q212E. For the field of MCT8 deficiency, it is important to assess the significance of MCT8 gene VUS.

A Novel G385E Variant in the Cold Region of the T3-Binding Domain of Thyroid Hormone Receptor Beta Gene and Investigations to Assess Its Clinical Significance.

BACKGROUND: Resistance to thyroid hormone beta (RTHß) is characterized by elevated thyroid hormone and unsuppressed thyroid-stimulating hormone (TSH), caused by thyroid hormone receptor beta gene (THRB) defects. Most mutations producing RTHß phenotype are located in CG-rich regions of THRB, encoding the T3-binding and hinge domains of the receptor. However, a region encompassing codons 384-425 is virtually devoid of RTHß-causing mutations, termed "cold region." CASE: A 49-year-old woman was diagnosed with Hashimoto thyroiditis in her twenties, and levothyroxine (LT4) was initiated. During LT4 treatment she had slightly elevated free thyroxine and TSH levels, suggesting the possibility of RTHß. RESULTS: Sequencing of THRB identified a heterozygous missense variant c.1154G>A producing p.G385E in the proband. Since this variant of unknown significance (VUS) has not been reported in RTHß individuals and considering its location in the "cold region" of THRB, we questioned its relevance. In silico functional prediction algorithms showed conflicting results: PolyPhen-2 predicted this VUS to be probably damaging with a score of 1.000, while SIFT predicted it to be tolerated with a score of 0.07, thus making additional investigations necessary. Genotyping of family members revealed that the proband's mother and sister, without RTHß phenotype, also harbored the same variant. This indicates that the THRB G385E variant is unlikely to manifest RTHß phenotype and confirms its "cold" status. CONCLUSIONS: This study illustrates that assigning causality of a THRB VUS for RTHß based only on in silico prediction algorithms is not always fully reliable. Additional phenotype-genotype segregation in family members can assist in predicting functional consequences of missense mutations.

Testicular enlargement in a pre-pubertal boy with adrenocortical tumour.

Adrenocortical tumours are rare in children. Virilisation caused by overproduction of adrenal androgens is the most common presentation. The testes of pre-pubertal boys with this tumour are usually small or of pre-pubertal size. A 4.8-year-old boy with an adrenocortical tumour and symmetrical pubertal-sized testes is reported. The serum testosterone level was 204 nmol/L (<0.7), dehydro-epiandrosterone-sulphate 56.7 µmol/L (<1.5) and luteinising and follicle-stimulating hormones were at suppressed levels. Histology demonstrated a diffusely increased mean tubular diameter of 90 µm (the size in a 12-year-old boy) and hyperplasia of Sertoli cells. There were no Leydig cells in the interstitial area. Prolonged exposure to an extraordinarily high testosterone level could have had stimulating effects on the seminiferous tubules and Sertoli cell growth and thus contributed to testicular enlargement.

Serum glypican 4 level in obese children and its relation to degree of obesity.

OBJECTIVE: Previous adult studies have demonstrated associations of serum glypican 4 (Gpc4) and obesity parameters and insulin sensitivity. However, an association of serum Gpc4 and glucose metabolism remains contradictory. Study of serum Gpc4 in obese children has not been conducted. We aimed to determine serum Gpc4 levels in obese children with various degrees of obesity. DESIGN, PATIENTS AND MEASUREMENTS: Up to 370 overweight and obese children, aged 6-18 years were enrolled in this cross-sectional study. Oral glucose tolerance test (OGTT) was performed with fasting serum Gpc4, lipid profiles, aspartate aminotransferase (AST) and alanine aminotransferase (ALT) measured. Insulin sensitivity and ß-cell function indices were calculated from plasma glucose and serum insulin levels derived from the OGTT. Bioelectrical impedance analysis was performed for body fat determination. Comparisons of serum Gpc4 levels among the groups of children with various degrees of obesity were performed. RESULTS: Serum Gpc4 levels progressively increased in children with increasing body mass index standard deviation score (BMI SDS) tertiles [median (interquartile range, IQR): 2.3 (1.8, 3.2), 2.6 (1.9, 3.4) and 3.2 (2.4, 3.8) µg/L, P<.001]. There were no differences in serum Gpc4 levels among children in the different glucose metabolism categories. Log serum Gpc4 levels were positively correlated with SDSs of weight and BMI, cholesterol, AST and ALT. No associations of log serum Gpc4 and insulin sensitivity and ß-cell function indices were demonstrated. CONCLUSIONS: Serum Gpc4 levels were increased with increasing degrees of obesity. There were no differences in serum Gpc4 levels among glucose metabolism categories.

Vitamin D deficiency and adrenal function in critically ill children.

BACKGROUND: Data on interrelationship between vitamin D deficiency (VDD) and adrenal insufficiency in critically ill children are limited. OBJECTIVE: To determine vitamin D status in critically ill children and its relationship with adrenal function. MATERIAL AND METHOD: Thirty-two patients and 36 controls were included. Serum 25-hydroxyvitamin D (25-OHD) levels were measured. Pediatric Risk of Mortality (PRISM) III score, outcome and adrenal function assessed by 1-microgram adrenocorticotropic hormone test were collected. RESULTS: Median (IQR) serum 25-OHD of thepatients was less than that of the controls (16.6 (13.3-19.5) vs. 24.2 (21.0-27.9) ng/mnL, p < 0.001). Twenty-five (78%) patients and seven (19%) controls had VDD. PRISM III score, proportions of patients with shock and vasopressive drug used, length of intensive care unit stay and ventilator used, and adrenal function were not different between patients with and without VDD. Patients with serum 25-OHD of less than 12 ng/mL had higher median (IQR) PRISM III score (14 (6-20) vs. 5 (2-10), p = 0.033) and higher proportion of mortality than those with serum 25-OHD of 12 ng/mL or greater. CONCLUSION: A greater proportion of VDD in critically ill children as compared with that of the controls was demonstrated. Serum 25-OHD was not associated with adrenal function.

Serum fibroblast growth factor 21 in overweight and obese Thai children and adolescents: its relation to glucose metabolism and its change after glucose loading.

OBJECTIVES: Fibroblast growth factor 21 (FGF21) has been demonstrated to be beneficial for glucose metabolism in animal and in vitro studies. However, its role in humans is still unclear. This study aimed to determine serum FGF21 in relation to glucose metabolism in obese children and to evaluate serum FGF21 changes during an oral glucose tolerance test (OGTT). DESIGN, PATIENTS AND MEASUREMENTS: A cross-sectional study of 301 obese children was conducted in a tertiary hospital. All children underwent an OGTT and had their fasting serum FGF21 and adiponectin measured. A subgroup of 71 children had their serum FGF21 levels serially measured at 0, 60 and 120 min during the OGTT. RESULTS: Serum FGF21 levels were progressively increased in children with normal glucose tolerance without hyperinsulinaemia, normal glucose tolerance with hyperinsulinaemia and abnormal glucose tolerance [median (IQR): 72 (34-148), 96 (55-182), 122 (75-220) pg/ml, respectively, P = 0·003]. Log serum FGF21 was associated with homoeostatic model assessment of insulin resistance (r = 0·174, P = 0·002). There was no correlation between log serum FGF21 and serum adiponectin level. During the OGTT, there were changes in serum FGF21 levels with a decrease in FGF21 at 60 min from the baseline and an increase above the baseline at 120 min. CONCLUSIONS: Serum FGF21 level was highest in obese children with the highest insulin resistance or abnormal glucose tolerance. Log serum FGF21 was not correlated with serum adiponectin. Changes in serum FGF21 levels during the OGTT were observed.