X-Linked Hypophosphatemia Management in Children: An International Working Group Clinical Practice Guideline.

Background: An International Working Group (IWG) developed new guidelines on the diagnosis, evaluation, management, and monitoring of X-linked hypophosphatemia (XLH) in children. Over the past 5 years, important advances have occurred in our understanding of the presentation, complications and treatment of XLH.

Methods: A group of 50 international experts in XLH from Canada, the United States, Europe, Asia and South America, along with methodology experts and patient partners, held 18 teleconference meetings in 2023-2024.

Canadian Association of Radiologists Pediatric Imaging Referral Guideline.

The Canadian Association of Radiologists (CAR) Pediatric Expert Panel is made up of pediatric physicians from the disciplines of radiology, emergency medicine, endocrinology, gastroenterology, general surgery, neurology, neurosurgery, respirology, orthopaedic surgery, otolaryngology, urology, a patient advisor, and an epidemiologist/guideline methodologist. After developing a list of 50 clinical/diagnostic scenarios, a rapid scoping review was undertaken to identify systematically produced referral guidelines that provide recommendations for one or more of these clinical/diagnostic scenarios. Recommendations from 32 guidelines and contextualization criteria in the Grading of Recommendations, Assessment, Development, and Evaluations (GRADE) for guidelines framework were used to develop 133 recommendation statements across the 50 scenarios.

X-linked hypophosphatemia, fibroblast growth factor 23 signaling, and craniosynostosis.

This review summarizes the current knowledge of fibroblast growth factor 23 signaling in bone and its role in the disease pathology of X-linked hypophosphatemia. Craniosynostosis is an under-recognized complication of X-linked hypophosphatemia. The clinical implications and potential cellular mechanisms invoked by increased fibroblast growth factor 23 signaling causing craniosynostosis are reviewed.

X-linked hypophosphatemia caused by a deep intronic variant in PHEX identified by PCR-based RNA analysis of urine-derived cells.

X-linked hypophosphatemia (XLH) is caused by dominant inactivating mutations in the phosphate regulating endopeptidase homology, X-linked (PHEX), resulting in elevated fibroblast growth factor 23 (FGF23), hypophosphatemia, rickets and osteomalacia. PHEX variants are identified in approximately 85 % of individuals with XLH, which leaves a substantial proportion of patients with negative DNA-based genetic testing. Here we describe a 16-year-old male who had typical features of XLH on clinical and radiological examination.

Leuprolide Acetate and QTc Interval in Gender-Diverse Youth.

Background: Puberty suppression is a standard of care for gender-affirming therapy in gender-diverse youth. Leuprolide acetate is a gonadotropin-releasing hormone agonist (GnRHa) commonly used for pubertal suppression. There are concerns that GnRHa agents prolong the rate-corrected QT interval (QTc) when used as androgen deprivation therapy in management of prostate cancer; however, there is a paucity of literature regarding the effect of leuprolide acetate on QTc intervals in gender-diverse youth.

Sickle cell bone disease and response to intravenous bisphosphonates in children.

Unlabelled: Children with sickle cell disease (SCD) have the potential for extensive and early-onset bone morbidity. This study reports on the diversity of bone morbidity seen in children with SCD followed at three tertiary centers. IV bisphosphonates were effective for bone pain analgesia and did not trigger sickle cell complications.

Regulation of 1 and 24 hydroxylation of vitamin D metabolites in the proximal tubule.

Calcium and phosphate are critical for numerous physiological processes. Consequently, the plasma concentration of these ions are tightly regulated. Calcitriol, the active form of vitamin D, is a positive modulator of mineralization as well as calcium and phosphate metabolism.

Metaphyseal and posterior rib fractures in osteogenesis imperfecta: Case report and review of the literature.

Purpose: Metaphyseal corner fractures and posterior rib fractures are thought to only occur in settings of inflicted injury. We describe a case of siblings who presented with metaphyseal corner fractures and multiple posterior rib fractures who were later found to carry mutations, a rare cause of Osteogenesis Imperfecta (OI) known as Bruck syndrome. This clinical presentation led to a literature review examining fracture types in OI and inflicted injury.

Incidence and Risk Factors for Hypoglycemia During Fetal-to-Neonatal Transition in Premature Infants.

To determine the incidence and risk factors associated with neonatal hypoglycemia in the premature population <33 weeks' gestation. This was a secondary retrospective analysis from previous infants enrolled in randomized controlled trials. A total of 255 infants <33 weeks' gestation were born during the study period.

46,XY disorder of sex development due to 17-beta hydroxysteroid dehydrogenase type 3 deficiency: a plea for timely genetic testing.

Background: 17β-hydroxysteroid dehydrogenase type 3 (17βHSD3) deficiency is a rare cause of disorder of sex development (DSD) due to impaired conversion of androstenedione to testosterone. Traditionally, the diagnosis was determined by βHCG-stimulated ratios of testosterone:androstenedione < 0.8.

Parenteral and oral antibiotic duration for treatment of pediatric osteomyelitis: a systematic review protocol.

Background: Pediatric osteomyelitis is a bacterial infection of bones requiring prolonged antibiotic treatment using parenteral followed by enteral agents. Major complications of pediatric osteomyelitis include transition to chronic osteomyelitis, formation of subperiosteal abscesses, extension of infection into the joint, and permanent bony deformity or limb shortening. Historically, osteomyelitis has been treated with long durations of antibiotics to avoid these complications.

Growth hormone production and action in N1E-115 neuroblastoma cells.

Neuroblastoma cells are undifferentiated cells derived from the neural crest and are commonly used as models for studying neural function. Mouse N1E-115 neuroblastoma cells are derived from cancerous tissue and provide a model for studying the oncogenesis of neural cells. As growth hormone (GH) has been implicated as an autocrine or paracrine involved in neural regulation and in the induction or progression of cancer, the possibility that N1E-115 cells are sites of GH production and GH action was assessed.

A high-conductance mode of a poly-3-hydroxybutyrate/calcium/polyphosphate channel isolated from competent Escherichia coli cells.

Reconstitution into planar lipid bilayers of a poly-3-hydroxybutyrate/calcium/polyphosphate (PHB/Ca(2+)/polyP) complex from Escherichia coli membranes yields cationic-selective, 100 pS channels (Das, S., Lengweiler, U.D.

A large, voltage-dependent channel, isolated from mitochondria by water-free chloroform extraction.

We examined ion channels derived from a chloroform extract of isolated, dehydrated rat liver mitochondria. The extraction method was previously used to isolate a channel-forming complex containing poly-3-hydroxybutyrate and calcium polyphosphate from Escherichia coli. This complex is also present in eukaryotic membranes, and is located primarily in mitochondria.