Rebound hypercalcaemia timing is associated with cumulative weight-based denosumab dose for central giant cell granuloma treatment in children despite a dose weaning regimen.

Central giant cell granulomas (CGCG) are locally destructive, non-neoplastic lesions that express receptor activator of nuclear factor-κB (RANK) and RANK ligand. Denosumab, a monoclonal antibody against RANK ligand, is licensed in skeletally mature patients, with less experience in children who are at risk of rebound hypercalcaemia. We describe the response to denosumab in five skeletally immature children with CGCG.

GNAQ/GNA11 Mosaicism Is Associated with Abnormal Serum Calcium Indices and Microvascular Neurocalcification.

Mosaic mutations in genes GNAQ or GNA11 lead to a spectrum of diseases including Sturge-Weber syndrome and phakomatosis pigmentovascularis with dermal melanocytosis. The pathognomonic finding of localized "tramlining" on plain skull radiography, representing medium-sized neurovascular calcification and associated with postnatal neurological deterioration, led us to study calcium metabolism in a cohort of 42 children. In this study, we find that 74% of patients had at least one abnormal measurement of calcium metabolism, the commonest being moderately low serum ionized calcium (41%) or high parathyroid hormone (17%).

Burosumab in management of X-linked hypophosphataemia: a retrospective cohort study of growth and serum phosphate levels.

Background: Burosumab, an antifibroblast growth factor 23 monoclonal antibody, improves rickets severity, symptoms and growth in children with X-linked hypophosphataemia (XLH) followed up to 64 weeks in clinical trials. International dosing guidance recommends targeting normal serum phosphate concentration; however, some children may not achieve this despite maximal dosing. This study compares clinical outcomes in children with XLH on long-term burosumab treatment who achieved normal phosphate versus those who did not.

Non-collagen pathogenic variants resulting in the osteogenesis imperfecta phenotype in children: a single-country observational cohort study.

Background/objectives: In England, children (0-18 years) with severe, complex and atypical osteogenesis imperfecta (OI) are managed by four centres (Birmingham, Bristol, London, Sheffield) in a 'Highly Specialised Service' (HSS OI); affected children with a genetic origin for their disease that is not in or form the majority of the 'atypical' group, which has set criteria for entry into the service. We have used the data from the service to assess the range and frequency of non-collagen pathogenic variants resulting in OI in a single country.

Methods: Children with atypical OI were identified through the HSS OI service database.

COPB2 loss of function causes a coatopathy with osteoporosis and developmental delay.

Coatomer complexes function in the sorting and trafficking of proteins between subcellular organelles. Pathogenic variants in coatomer subunits or associated factors have been reported in multi-systemic disorders, i.e.

Genetic Analysis of Pediatric Primary Adrenal Insufficiency of Unknown Etiology: 25 Years' Experience in the UK.

Context: Although primary adrenal insufficiency (PAI) in children and young people is often due to congenital adrenal hyperplasia (CAH) or autoimmunity, other genetic causes occur. The relative prevalence of these conditions is poorly understood.

Objective: We investigated genetic causes of PAI in children and young people over a 25 year period.

Endocrine Diseases of Newborn: Epidemiology, Pathogenesis, Therapeutic Options, and Outcome "Current Insights Into Disorders of Calcium and Phosphate in the Newborn".

The physiology and regulation of bone minerals in the fetus and the newborn is significantly different from children and adults. The bone minerals calcium, phosphate and magnesium are all maintained at higher concentrations to achieve adequate bone accretion. This is an integral component of normal fetal development which facilitates safe neonatal transition to post-natal life.

Case report: a 10-year-old girl with primary hypoparathyroidism and systemic lupus erythematosus.

Objectives Hypoparathyroidism is a rare disease in children that occurs as a result of autoimmune destruction of the parathyroid glands, a defect in parathyroid gland development or secondary to physical parathyroid gland disturbance. Typical symptoms of hypoparathyroidism present as hypocalcaemia and hyperphosphatemia due to decreased parathyroid hormone secretion and may lead to nerve and muscles disturbances resulting in clinical manifestation of tetany, arrhythmias and epilepsy. Currently, there is no conventional hormone replacement treatment for hypoparathyroidism and therapeutic approaches include normalising mineral levels using an oral calcium supplement and active forms of vitamin D.

Juvenile Paget's disease with compound heterozygous mutations in TNFRSF11B presenting with recurrent clavicular fractures and a mild skeletal phenotype.

Juvenile Paget's disease (JPD) is a rare recessively-inherited bone dysplasia. The great majority of cases described to date have had homozygous mutations in TNFRSF11B, the gene encoding osteoprotegerin. We describe a boy who presented with recurrent clavicular fractures following minor trauma (8 fractures from age 2 to 11).

A New Multisystem Disorder Caused by the Gαs Mutation p.F376V.

Context: The α subunit of the stimulatory G protein (Gαs) links numerous receptors to adenylyl cyclase. Gαs, encoded by GNAS, is expressed predominantly from the maternal allele in certain tissues. Thus, maternal heterozygous loss-of-function mutations cause hormonal resistance, as in pseudohypoparathyroidism type Ia, whereas somatic gain-of-function mutations cause hormone-independent endocrine stimulation, as in McCune-Albright syndrome.

Use of insulin pump therapy in children and adolescents with type 1 diabetes and its impact on metabolic control: comparison of results from three large, transatlantic paediatric registries.

Aims/hypothesis: While the use of insulin pumps in paediatrics has expanded dramatically, there is still considerable variability among countries in the use of pump technology. The present study sought to describe differences in metabolic control and pump use in young people with type 1 diabetes using data collected in three multicentre registries.

Methods: Data for the years 2011 and 2012 from 54,410 children and adolescents were collected from the Prospective Diabetes Follow-up Registry (DPV; n = 26,198), T1D Exchange (T1DX; n = 13,755) and the National Paediatric Diabetes Audit (NPDA; n = 14,457).

Rates of diabetic ketoacidosis: international comparison with 49,859 pediatric patients with type 1 diabetes from England, Wales, the U.S., Austria, and Germany.

Objective: Diabetic ketoacidosis (DKA) in children and adolescents with established type 1 diabetes is a major problem with considerable morbidity, mortality, and associated costs to patients, families, and health care systems. We analyzed data from three multinational type 1 diabetes registries/audits with similarly advanced, yet differing, health care systems with an aim to identify factors associated with DKA admissions.

Research Design And Methods: Data from 49,859 individuals <18 years with type 1 diabetes duration ≥1 year from the Prospective Diabetes Follow-up Registry (DPV) initiative (n = 22,397, Austria and Germany), the National Paediatric Diabetes Audit (NPDA; n = 16,314, England and Wales), and the T1D Exchange (T1DX; n = 11,148, U.

Case Histories.

Conditions related to abnormalities of calcium and bone metabolism are large in number and are characterised by hypocalcaemia, hypercalcaemia, primary and secondary osteoporosis, rickets resulting from both vitamin D and phosphate metabolism disorders, and a series of miscellaneous conditions. Included in this chapter is a series of cases drawn from our clinics and from colleagues who have presented these clinical problems at the recent Advanced Courses in Paediatric Bone and Calcium Metabolism run by the British Paediatric and Adolescent Bone group. This series of cases is not fully comprehensive but is designed to cover the major aspects of bone- and calcium-related disorders.

Classification of Disorders of Bone and Calcium Metabolism.

Classification is a natural human trait that enables us to put what may otherwise be very complex subjects into some order. However, classification should be seen not as an end in itself but rather as a means to help us understand certain topics. In the case of medicine, classification helps to provide information about the causes underlying many of the conditions encountered and, in some cases, provides a rationale for developing new treatments.

A Practical Approach to Vitamin D Deficiency and Rickets.

Rickets is a condition in which there is failure of the normal mineralisation (osteomalacia) of growing bone. Whilst osteomalacia may be present in adults, rickets cannot occur. It is generally caused by a lack of mineral supply, which can either occur as a result of the deficiency of calcium (calciopaenic rickets, now known as parathyroid hormone-dependent rickets) or of phosphate (phosphopaenic rickets, now called FGF23-dependent rickets).

Physiology of Calcium, Phosphate, Magnesium and Vitamin D.

The physiology of calcium and the other minerals involved in its metabolism is complex and intimately linked to the physiology of bone. Five principal humoral factors are involved in maintaining plasma concentrations of calcium, magnesium and phosphate and in coordinating the balance between their content in bone. The transmembrane transport of these elements is dependent on a series of complex mechanisms that are partly controlled by these hormones.

Voyages of Discovery.

The metabolism of calcium and bone is controlled by five principal hormones: parathyroid hormone, 1,25-dihydroxyvitamin D, calcitonin, parathyroid hormone-related peptide and fibroblast growth factor 23, some of which have been known for several decades and some of which have only more recently been identified. The stories of the discovery of these hormones have constituted a series of complex journeys that have been undertaken over the past century or so, none of which has yet been completed. The complexities of bone and calcium metabolism have been and remain, to many people, somewhat mysterious and a daunting task to understand.

Anticonvulsant treatment associated with intractable hypocalcaemia in a female child with hypoparathyroidism.

Background: We report the case of a female infant with hypoparathyroidism due to an activating mutation in the calcium-sensing receptor gene.

Case Report: The child presented in the neonatal period with clinical seizures associated with severe hypocalcaemia, hyperphosphataemia, low parathyroid hormone levels and elevated urine calcium:creatinine ratios. She required intravenous calcium and phenobarbitone initially, and then oral 1-alfacalcidol (1-AC) and phenobarbitone were started.

Mutational analysis of the adaptor protein 2 sigma subunit (AP2S1) gene: search for autosomal dominant hypocalcemia type 3 (ADH3).

Context: Autosomal dominant hypocalcemia (ADH) types 1 and 2 are due to calcium-sensing receptor (CASR) and G-protein subunit-α11 (GNA11) gain-of-function mutations, respectively, whereas CASR and GNA11 loss-of-function mutations result in familial hypocalciuric hypercalcemia (FHH) types 1 and 2, respectively. Loss-of-function mutations of adaptor protein-2 sigma subunit (AP2σ 2), encoded by AP2S1, cause FHH3, and we therefore sought for gain-of-function AP2S1 mutations that may cause an additional form of ADH, which we designated ADH3.

Objective: The objective of the study was to investigate the hypothesis that gain-of-function AP2S1 mutations may cause ADH3.

Towards a safety net for management of 22q11.2 deletion syndrome: guidelines for our times.

Unlabelled: The commonest autosomal deletion, 22q11.2 deletion syndrome (22q11DS) is a multisystem disorder varying greatly in severity and age of identification between affected individuals. Holistic care is best served by a multidisciplinary team, with an anticipatory approach.