Aneta Gawlik

Autosomal-Recessive Mutations in SLC34A1 Encoding Sodium-Phosphate Cotransporter 2A Cause Idiopathic Infantile Hypercalcemia

Idiopathic infantile hypercalcemia (IIH) is characterized by severe hypercalcemia with failure to thrive, vomiting, dehydration, and nephrocalcinosis. Recently, mutations in the vitamin D catabolizing enzyme 25-hydroxyvitamin D3-24-hydroxylase (CYP24A1) were described that lead to increased sensitivity to vitamin D due to accumulation of the active metabolite 1,25-(OH)2D3. In a subgroup of patients who presented in early infancy with renal phosphate wasting and symptomatic hypercalcemia, mutations in CYP24A1 were excluded. Four patients from families with parental consanguinity were subjected to homozygosity mapping that identified a second IIH gene locus on chromosome 5q35 with a maximum logarithm of odds (LOD) score of 6.79. The sequence analysis of the most promising candidate gene, SLC34A1 encoding renal sodium-phosphate cotransporter 2A (NaPi-IIa), revealed autosomal-recessive mutations in the four index cases and in 12 patients with sporadic IIH. Functional studies of mutant NaPi-IIa in Xenopus oocytes and opossum kidney (OK) cells demonstrated disturbed trafficking to the plasma membrane and loss of phosphate transport activity. Analysis of calcium and phosphate metabolism in Slc34a1-knockout mice highlighted the effect of phosphate depletion and fibroblast growth factor-23 suppression on the development of the IIH phenotype. The human and mice data together demonstrate that primary renal phosphate wasting caused by defective NaPi-IIa function induces inappropriate production of 1,25-(OH)2D3 with subsequent symptomatic hypercalcemia. Clinical and laboratory findings persist despite cessation of vitamin D prophylaxis but rapidly respond to phosphate supplementation. Therefore, early differentiation between SLC34A1 (NaPi-IIa) and CYP24A1 (24-hydroxylase) defects appears critical for targeted therapy in patients with IIH.

Incidence and Dynamics of Thyroid Dysfunction and Thyroid Autoimmunity in Girls with Turner’s Syndrome: A Long-Term Follow-Up Study

Objective: Clinical studies suggest that the thyroid autoantibodies and/or hypothyroidism are not present in Turner’s syndrome (TS) patients before the age of 8 years and are more frequent in patients with the X isochromosome. The aim of the study was to analyze the dynamics of thyroid dysfunction in girls with TS. Design: 86 TS patients with a median age of 10.6 years were followed for 4.6 ± 3.0 years. Outcomes: The prevalence of thyroid abnormalities increased from 25.5 to 50% during the follow-up. Finally, 31 (36%) patients had positive thyroid autoantibodies and 27 (31.4%) had subclinical hypothyroidism. Hashimoto’s thyroiditis was diagnosed in 15 patients. Median age of developing thyroid antibodies and subclinical hypothyroidism was 14.1 and 14.8 years, respectively. The youngest hypothyroid patient was 1.8 years old and the youngest girl with positive anti-thyroid antibodies was 5.5 years old. Autoantibodies appeared mainly after the age of 13. The risk of developing subclinical hypothyroidism was greatest between 12 and 14 years of age. The prevalence of thyroid abnormalities was not related to the karyotype. Conclusions: Thyroid autoimmunity and dysfunctions in TS may start early, their prevalence increases with age, independently of karyotype and without any clinical symptoms and signs.

Quality of Medical Follow-Up of Young Women with Turner Syndrome Treated in One Clinical Center

For Turner syndrome (TS) patients, smooth transition from pediatric to adult health care is a critical point. The study objective was to evaluate the medical follow-up of young women with TS in one clinical center 3 years after the latest guidelines had been introduced by the TS Study Group. A questionnaire study was performed in 59 TS adults selected from a database of 117 patients. Twenty-two of them, aged 23.0 ± 2.8 years, consented to participate. Nineteen responders (86.4%) were followed up by general practitioners who were not aware of the TS diagnosis in 14 (63.6%) cases. Eight (36.4%) were seen regularly by the relevant specialists. Adequate medical assessment varied from 5% (celiac serology) to 74% (gynecology assessment) and 82% (ear-nose-throat) of participants. None of the patients had undergone all of the recommended investigations according to recommendation. Height deficiency, body mass index, age at TS diagnosis and level of education did not correlate with the number of assessments performed (p = 0.687, p = 0.810, p = 0.641, and p = 0.568, respectively). Three years after the introduction of the current guidelines, medical follow-up in the transition phase is still inadequate. Improvement in transitional health care is warranted through better patient education, referring to physicians caring for adults with TS and better cooperation with general practitioners with wider popularization of the TS recommendations among them.

TRANSITION IN ENDOCRINOLOGY: Treatment of Turner's syndrome during transition

Transition in health care for young patients with Turners syndrome (TS) should be perceived as a staged but uninterrupted process starting in adolescence and moving into adulthood. As a condition associated with high risk of short stature, cardiovascular diseases, ovarian failure, hearing loss and hypothyroidism, TS requires the attention of a multidisciplinary team. In this review paper, we systematically searched the relevant literature from the last decade to discuss the array of problems faced by TS patients and to outline their optimal management during the time of transfer to adult service. The literature search identified 233 potentially relevant articles of which 114 were analysed. The analysis confirmed that all medical problems present during childhood should also be followed in adult life. Additionally, screening for hypertension, diabetes mellitus, dyslipidaemia, and osteoporosis is needed. After discharge from the paediatric clinic, there is still a long way to go.

Duodenal Expression of 25 Hydroxyvitamin D3-1α-hydroxylase Is Higher in Adolescents Than in Children and Adults.

CONTEXT Puberty is associated with increased dietary calcium absorption. However, little is known about the metabolic adaptations that enhance calcium absorption during puberty. OBJECTIVES To investigate duodenal 25-hydroxy vitamin D-1α-hydroxylase (CYP 27B1) mRNA expression and duodenal 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) production in children, adolescents, and adults. DESIGN AND METHODS CYP27B1a nd IGF1 mRNA expression and 1,25(OH)2D3 production were determined in duodenal biopsies. CYP27B1 expression was also determined after IGF1R inhibitor treatment of human and mice duodenal explants. mRNA expression was determined by RT-PCR, and CYP27B1 activity was determined by incubating duodenal explants with 25(OH)D3 and measuring 1,25(OH)2D3 production by radioimmunoassay. RESULTS CYP27B1 mRNA expression was 13.7 and 10.4 times higher in biopsies from adolescents compared to adults and children, respectively. IGF1 mRNA expression was 30% and 45% higher in explants from adolescents and children, respectively, compared to adults. Inhibition of IGF1 receptor activity decreased CYP27B1 expression in explants from both mice (85%) and humans (24%). 1,25(OH)2D3 production reached a maximum velocity of 768 ± 268 pmol/l/mg protein at 748.8 nmol/l of 25(OH)D3 in children and adolescents, whereas the maximum velocity was 86.4 ± 43.2 pmol/l/mg protein in adults. The substrate concentration at which the enzyme shows half of its maximum activity was similar in all groups, ranging between 624 and 837 nmol/L of 25(OH)D3. CONCLUSIONS Increased CYP27B1 expression and local duodenal 1,25(OH)2D3 production during puberty may be a metabolic adaptation that promotes dietary calcium absorption. IGF1, a major factor in skeletal growth, is also involved in the modulation of CYP27B1 expression in the gut and may increase calcium supply for the growing bone.

Subclinical Hypothyroidism in Children and Adolescents: Is It Clinically Relevant?

Although subclinical hypothyroidism (SH) is a common clinical problem, its diagnosis tends to be incidental. According to the definition, it should be asymptomatic, only detectable by screening. The presence or coincidence of any symptoms leads to L-thyroxine treatment. The clinical presentation, especially in younger patients with subclinical hypothyroidism, is still under dispute. Accordingly, the aim of this paper was to review the literature from the past seven years. The literature search identified 1,594 potentially relevant articles, of which 24 met the inclusion criteria. Few studies focus on the symptomatology of subclinical hypothyroidism, and most of them analyzed a small number of subjects. A significant correlation was found by some authors between subclinical hypothyroidism and a higher risk of hypertension, dyslipidemia, and migraine. No evidence of the impact of subclinical hypothyroidism on weight, growth velocity, and puberty was revealed. As the quality of most studies is poor and no definite conclusions can be drawn, randomized, large-scale studies in children and adolescents are warranted to determine the best care for patients with SH.

Blood pressure regulation and resting heart rate abnormalities in adolescent girls with polycystic ovary syndrome

OBJECTIVE To assess the risk of cardiovascular disease on the basis of biochemical, echocardiographic, and 24-hour blood pressure (BP) monitoring parameters in adolescent girls with polycystic ovary syndrome (PCOS). DESIGN Cross-sectional study. SETTING Academic and research institution. PATIENT(S) Thirty-four obese and nonobese girls with PCOS were evaluated and compared with body mass index-matched girls with regular menses. INTERVENTION(S) None. MAIN OUTCOME MEASURE(S) Androgens, gonadotropins, lipids, and fasting and oral glucose tolerance test-stimulated glucose and insulin concentrations were measured. Echocardiographic assessment and 24-hour BP monitoring were done. RESULT(S) Compared with obese controls, obese girls with PCOS had significantly higher 24-hour mean BP, day mean BP, day diastolic BP, and diastolic BP nighttime dip (75.5 ± 4.5 mm Hg vs. 71.7 ± 3.7 mm Hg; 78.2 ± 5.0 mm Hg vs. 73.6 ± 4.0 mm Hg; 67.6 ± 4.9 mm Hg vs. 63.7 ± 3.7 mm Hg; and 20.2% ± 5.2% vs. 15.0% ± 6.6%, respectively). Obese girls with PCOS had significantly higher night heart rate than obese controls (60.4 ± 5.6 beats per minute vs. 61.7 ± 4.8 beats per minute). Left ventricle end-diastolic (4.6 ± 0.3 cm vs. 4.2 ± 0.2 cm) and end-systolic diameter (3.0 ± 0.3 cm vs. 2.7 ± 0.2 cm) were also significantly higher in nonobese girls with PCOS than in nonobese controls; however, all values were still within the accepted range of normal limits. CONCLUSION(S) Higher night heart rate in obese girls with PCOS and higher day BP but preserved diastolic nocturnal dip in nonobese girls with PCOS may be regarded as early cardiovascular disease risk factors.

Validation of growth charts for girls with Turner syndrome

Growth charts, which describe the natural course of growth in Turner syndrome (TS) patients, are commonly used in studies in lieu of control groups. While analysing data, various charts produce different final height estimations and height‐gain predictions. The choice of an appropriate chart should be the first task when assessing effects of growth hormone treatment. The purpose of this study was to establish the most appropriate growth chart for the subsequent analysis of growth rate in the patients with TS observed initially for a short time without treatment in our clinic.

Diagnostics and treatment of differentiated thyroid carcinoma in children - Guidelines of Polish National Societies.

1Department of Paediatric Endocrinology and Rheumatology, Poznan University of Medical Sciences, Poznan, Poland 2Department of Nuclear Medicine and Endocrine Oncology, Maria Sklodowska-Curie Memorial Cancer Centre and Institute of Oncology, Gliwice Branch, Gliwice, Poland. 3Department of Paediatrics and Paediatric Endocrinology, School of Medicine in Katowice, Medical University of Silesia, Katowice, Poland 4Department of Oncological and Reconstructive Surgery, Maria Sklodowska-Curie Memorial Cancer Centre and Institute of Oncology, Gliwice Branch, Gliwice, Poland 5Department of Oncological Endocrinology and Nuclear Medicine, Centre of Oncology – Maria Sklodowska-Curie Memorial Institute, Warsaw, Poland 6Department of Tumour Pathology, Maria Sklodowska-Curie Memorial Cancer Centre and Institute of Oncology, Gliwice Branch, Gliwice, Poland 7Department of Paediatrics and Endocrinology, Medical University, Warsaw, Poland 8Department of General and Oncological Surgery, Medical University of Lodz, Lodz, Poland 9Private practice, Katowice, Poland 10Department of Paediatric Surgery and Urology, Wroclaw Medical University, Wroclaw, Poland 11Department of Morphometry of Endocrine Glands, Chair of Endocrinology, Medical University of Lodz, Lodz, Poland 12Department of Dental Pathology, Medical University of Lodz, Lodz, Poland 13Department of Tumour Pathology, Poznan University of Medical Sciences, Poznan, Poland 14Department of Endocrinology, Metabolism and Internal Medicine, Poznan University of Medical Sciences, Poznan, Poland 15Department of Endocrinology and Metabolic Diseases, Polish Mother’s Memorial Hospital-Research Institute, Medical University of Lodz, Lodz, Poland

Lessons from the life history of natural fertility societies on child growth and maturation.

During the evolution of hominids, childhood and adolescence have been added as new life-history phases. The transition from infancy to childhood (ICT) confers a predictive adaptive response to energetic cues that strongly influence adult height, whereas the transition from juvenility to adolescence establishes longevity and the age of fertility. Evolutionary short-term adaptations to energy crises apparently use epigenetic mechanisms that defer the ICT, culminating in short stature. The study of hunter-gatherers gives us an indication of pre-demographic transition populations and their life style that prevailed for 99% of homos evolution. The secular trend for receding age of pubertal development has been an adaptive response to positive environmental cues in terms of energy balance. In natural fertility preindustrial societies with limited access to modern contraception and health care, and whose economies are primarily subsistence-based, most resources are invested as somatic capital in human body size and fertility. Here we review results from databases for natural fertility societies, with the information on life history, population density, height and body mass, indices of adolescence and fertility. By using them it was possible to verify the ICT model as well as to explore pubertal parameters that are related to evolutionary fitness. They confirmed that body size was adaptively smaller in hostile environments, and was tightly associated with reproductive fitness.