Rare diseases of phosphate and calcium metabolism: Crossing glances between nephrology and endocrinology.

Rare diseases of phosphate/calcium metabolism correspond to a wide and heterogeneous spectrum of diseases. Recent knowledge in physiology and genetics has made it possible to better characterize them and to propose attractive therapeutic approaches based on the underlying pathophysiology. These diseases are often at the interface between nephrology and endocrinology.

Association between 25(OH) vitamin D and graft survival in renal transplanted children.

Background: In children, vitamin D deficiency is common after renal transplantation. Besides promoting bone and muscle development, vitamin D has immunomodulatory effects, which could protect kidney allografts. The purpose of this study was to assess the association between vitamin D status and the occurrence of renal rejection.

The interest of oral calcium loads test in the diagnosis and management of pediatric nephrolithiasis with hypercalciuria: Experience from a tertiary pediatric centre.

Introduction: The use of calcium load has been forgotten in pediatrics until recently whereas it is of utmost importance to have a practical approach to guide management of hypercalciuric nephrolithiasis.

Objective: The purpose of this study was to evaluate the practical interest of oral calcium loads to improve the overall management of nephrolithiasis in children.

Methods: We retrospectively studied all pediatric patients having undergone an oral calcium load in our pediatric nephrology unit between September 2015 and April 2017.

Bone Disease in Nephropathic Cystinosis: Beyond Renal Osteodystrophy.

Patients with chronic kidney disease (CKD) display significant mineral and bone disorders (CKD-MBD) that induce significant cardiovascular, growth and bone comorbidities. Nephropathic cystinosis is an inherited metabolic disorder caused by the lysosomal accumulation of cystine due to mutations in the gene encoding cystinosin, and leads to end-stage renal disease within the second decade. The cornerstone of management relies on cysteamine therapy to decrease lysosomal cystine accumulation in target organs.

Hyperphosphatemia and Chronic Kidney Disease: A Major Daily Concern Both in Adults and in Children.

Hyperphosphatemia is common in chronic kidney disease (CKD). Often seen as the "silent killer" because of its dramatic effect on vascular calcifications, hyperphosphatemia explains, at least partly, the onset of the complex mineral and bone disorders associated with CKD (CKD-MBD), together with hypocalcemia and decreased 1-25(OH) vitamin D levels. The impact of CKD-MBD may be immediate with abnormalities of bone and mineral metabolism with secondary hyperparathyroidism and increased FGF23 levels, or delayed with poor growth, bone deformities, fractures, and vascular calcifications, leading to increased morbidity and mortality.

Shortened Fingers and Toes: GNAS Abnormalities are Not the Only Cause.

The PTH/PTHrP receptor (PTHR1) mediates the actions of parathyroid hormone (PTH) and PTH-related peptide (PTHrP) by coupling this G protein-coupled receptor (GPCR) to the alpha-subunit of the heterotrimeric stimulatory G protein (Gsα) and thereby to the formation of cAMP. In growth plates, PTHrP-dependent activation of the cAMP/PKA second messenger pathway prevents the premature differentiation of chondrocytes into hypertrophic cells resulting in delayed growth plate closure. Heterozygous mutations in , the gene encoding Gsα, lead to a reduction in cAMP levels in growth plate chondrocytes that is sufficient to cause shortening of metacarpals and/or -tarsals, i.

Treatment of hyperphosphatemia: the dangers of high PTH levels.

The control of secondary hyperparathyroidism (SHPT) in pediatric chronic kidney disease is of utmost importance. Even though parathyroid hormone (PTH) is an important biomarker of mineral and bone disorders associated to CKD (CKD-MBD), calcium, phosphate, alkaline phosphatase, and vitamin D are also crucial and should be assessed together. In pediatric dialysis, high PTH levels have been associated with impaired longitudinal growth, bone disease, cardiovascular comorbidities, left ventricular hypertrophy, anemia, and even mortality (when PTH levels were above 500 pg/mL, i.

Assessment of mineral and bone biomarkers highlights a high frequency of hypercalciuria in asymptomatic healthy teenagers.

Aim: Assessment of mineral metabolism is complex in paediatrics.

Methods: We assessed the evolution of the main mineral and bone biomarkers (total/bone alkaline phosphatase ALP/BAP, β-crosslaps, osteocalcin, sclerostin, C-terminal and intact FGF23) in 100 healthy teenagers (10-18 years, 50 boys).

Results: At a mean age of 13.

Progression of Mineral Ion Abnormalities in Patients With Jansen Metaphyseal Chondrodysplasia.

Context: Five different activating PTH/PTH-related peptide (PTHrP) receptor (PTHR1) mutations have been reported as causes of Jansen metaphyseal chondrodysplasia (JMC), a rare disorder characterized by severe growth plate abnormalities and PTH-independent hypercalcemia.

Objectives: Assess the natural history of clinical and laboratory findings in 24 patients with JMC and characterize the disease-causing mutant receptors in vitro.

Patients And Methods: The H223R mutation occurred in 18 patients.

[Vitamin D status in 6- to 10-year-old children: a French multicenter study in 326 children].

Objective: To assess the vitamin D status of children aged 6-10years in the French general population for whom no guidelines have yet been defined due to insufficient data.

Method: The study was conducted during two winters with very different sunshine levels: 5 March to 17 April 2012 and 8 January to 16 April 2013 in 20 then 22 centers. Three hundred children (60 children for each year of age) attending an ambulatory care unit or outpatient department for a reason unrelated to vitamin D status were included at the end of winter in 20 hospital centers (ten centers in the northern half of France above latitude 46-47°N/Lille: 50°N and ten centers in the southern half of France below latitude 46-47°N/Marseille: 43°N).

Usefulness of bone density measurement in fallers.

The objective of this systematic literature review is to discuss the latest French recommendation issued in 2012 that a fall within the past year should lead to bone mineral density (BMD) measurement using dual-energy X-ray absorptiometry (DXA). This recommendation rests on four facts. First, osteoporosis and fall risk are the two leading risk factors for nonvertebral fractures in postmenopausal women.

[Prophylactic prescription of vitamin D in France: national multicenter epidemiological study of 3240 children under 6 years of age].

Aims: The aim of the study was to assess compliance with the current recommendations of prophylactic prescription of vitamin D via a multicentric cross-sectional epidemiological survey of 3240 children under 6 years of age.

Method: Parent questionnaires and data from the health records of children presenting to the emergency departments of 25 teaching hospitals and hospital centers provided information on the children's characteristics, their prescriptions, and other vitamin D intake. Based on the currently applicable recommendations, intakes of 600-1,200 IU/day - 900-1500 IU/day for children with pigmented skin and/or premature and/or hypotrophic children - are considered adequate.