Challenges in Hypophosphatasia: Suspicion, Diagnosis, Genetics, Management, and Follow-Up.

Background: Hypophosphatasia (HPP) is a rare genetic disorder caused by loss-of-function variants in the ALPL gene, leading to deficient tissue-nonspecific alkaline phosphatase (ALP) activity. This results in a distinctive biochemical profile marked by low serum ALP levels and elevated pyridoxal-5-phosphate (PLP). The clinical spectrum of HPP ranges from perinatal lethality to asymptomatic cases, presenting significant diagnostic and therapeutic challenges.

Chromosome 20p11.2 deletions cause congenital hyperinsulinism via the loss of FOXA2 or its regulatory elements.

Persistent congenital hyperinsulinism (HI) is a rare genetically heterogeneous condition characterised by dysregulated insulin secretion leading to life-threatening hypoglycaemia. For up to 50% of affected individuals screening of the known HI genes does not identify a disease-causing variant. Large deletions have previously been used to identify novel regulatory regions causing HI.

A patient-centred and multi-stakeholder co-designed observational prospective study protocol: Example of the adolescent experience of treatment for X-linked hypophosphataemia (XLH).

The importance of patient centricity and keeping the patient at the heart of research design is now well recognised within the healthcare community. The involvement of patient, caregiver and clinician representatives in the study design process may help researchers to achieve this goal and to ensure robust and meaningful data generation. Real-world data collection allows for a more flexible and patient-centred research approach for gaining important insights into the experience of disease and treatments, which is acutely relevant for rare diseases where knowledge about the disease is more likely to be limited.

Diabetes control is worse in children and young people with type 1 diabetes requiring interpreter support.

Introduction: Language barriers can pose a significant hurdle to successfully educating children and young people with type 1 diabetes (CYPD) and their families, potentially influencing their glycaemic control.

Methods: Retrospective case-control study assessing HbA1c values at 0, 3, 6, 9, 12 and 18 months post-diagnosis in 41 CYPD requiring interpreter support (INT) and 100 age-, sex- and mode-of-therapy-matched CYPD not requiring interpreter support (CTR) in our multi-diverse tertiary diabetes centre. Data were captured between 2009-2016.

Hypoglycaemia in adrenal insufficiency.

Adrenal insufficiency encompasses a group of congenital and acquired disorders that lead to inadequate steroid production by the adrenal glands, mainly glucocorticoids, mineralocorticoids and androgens. These may be associated with other hormone deficiencies. Adrenal insufficiency may be primary, affecting the adrenal gland's ability to produce cortisol directly; secondary, affecting the pituitary gland's ability to produce adrenocorticotrophic hormone (ACTH); or tertiary, affecting corticotrophin-releasing hormone (CRH) production at the level of the hypothalamus.

Bi-allelic mutation in SEC16B alters collagen trafficking and increases ER stress.

Osteogenesis imperfecta (OI) is a genetically and clinically heterogeneous disorder characterized by bone fragility and reduced bone mass generally caused by defects in type I collagen structure or defects in proteins interacting with collagen processing. We identified a homozygous missense mutation in SEC16B in a child with vertebral fractures, leg bowing, short stature, muscular hypotonia, and bone densitometric and histomorphometric features in keeping with OI with distinct ultrastructural features. In line with the putative function of SEC16B as a regulator of trafficking between the ER and the Golgi complex, we showed that patient fibroblasts accumulated type I procollagen in the ER and exhibited a general trafficking defect at the level of the ER.

Heterozygous mutation causing hyperparathyroidism in children and adolescents: a report of 2 cases.

Objectives: Primary hyperparathyroidism (PHPT), whilst common in elderly populations, is rare in adolescents. Hereditary cases make up less than 10% of patients with PH. We report two patients with mutation presenting in early adolescence.

mutation in LDS3 causes bone fragility by impairing the TGF-β pathway and enhancing osteoclastogenesis.

Loss-of-function mutations in cause Loeys-Dietz syndrome type 3 (LDS3), a rare autosomal-dominant connective tissue disorder characterized by vascular pathology and skeletal abnormalities. Dysregulation of TGF-β/SMAD signaling is associated with abnormal skeletal features and bone fragility. To date, histomorphometric and ultrastructural characteristics of bone with mutations have not been reported in humans and the exact mechanism by which mutations cause the LDS3 phenotype is poorly understood.

Infigratinib in children with achondroplasia: the PROPEL and PROPEL 2 studies.

Background: Achondroplasia is the most common short-limbed skeletal dysplasia resulting from gain-of-function pathogenic variants in fibroblast growth factor receptor 3 () gene, a negative regulator of endochondral bone formation. Most treatment options are symptomatic, targeting medical complications. Infigratinib is an orally bioavailable, FGFR1-3 selective tyrosine kinase inhibitor being investigated as a direct therapeutic strategy to counteract FGFR3 overactivity in achondroplasia.

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.

Monitoring Skull Base Abnormalities in Children with Osteogenesis Imperfecta - Review of Current Practice and a Suggested Clinical Pathway.

Objectives: In the context of a lack of national consensus on the benefits of skull base imaging in children with osteogenesis imperfecta (OI), this study aims to analyse and correlate the clinical symptoms and radiological images of children with severe OI.

Methods: A retrospective case notes and image analysis was carried out on children with complex OI between 2012 and 2018 at a specialist tertiary centre. Data were collected on patient demographic factors, clinical data, imaging findings (presence of Wormian bones, platybasia, basilar impression (McGregor's technique) and basilar invagination (McRae's technique)), and clinical features at the time of imaging.

Neonatal Bone Disorders.

Neonatologists care for newborns with either an antenatal suspicion or postnatal diagnosis of bone disease. With improved ultrasound imaging techniques, more cases of neonatal bone disorders are identified antenatally and this requires further diagnostic/molecular testing either antenatally or soon after birth for confirmation of the diagnosis and facilitating subsequent management. Prompt diagnosis is vital in certain conditions where initiation of treatment is time critical and life saving.

DYNAMIC: Dynamic glucose management strategies delivered through a structured education program improves time in range in a socioeconomically deprived cohort of children and young people with type 1 diabetes with a history of hypoglycemia.

Objectives: Create and evaluate the effectiveness of a structured education program in children and young people (CYP) with type 1 diabetes using continuous glucose monitoring (CGM).

Design And Methods: Step 1: CGM devices were evaluated for predetermined criteria using a composite score. Step 2: The education program was developed following review of international structured education guidance, dynamic glucose management (DynamicGM) literature, award-winning diabetes educators' websites, and CGM user feedback.

Clinical guidelines for burosumab in the treatment of XLH in children and adolescents: British paediatric and adolescent bone group recommendations.

X-linked hypophosphataemia (XLH) is caused by a pathogenic variant in the PHEX gene, which leads to elevated circulating FGF23. High FGF23 causes hypophosphataemia, reduced active vitamin D concentration and clinically manifests as rickets in children and osteomalacia in children and adults. Conventional therapy for XLH includes oral phosphate and active vitamin D analogues but does not specifically treat the underlying pathophysiology of elevated FGF23-induced hypophosphataemia.

Recommendations for Diagnosis and Treatment of Pseudohypoparathyroidism and Related Disorders: An Updated Practical Tool for Physicians and Patients.

Patients affected by pseudohypoparathyroidism (PHP) or related disorders are characterized by physical findings that may include brachydactyly, a short stature, a stocky build, early-onset obesity, ectopic ossifications, and neurodevelopmental deficits, as well as hormonal resistance most prominently to parathyroid hormone (PTH). In addition to these alterations, patients may develop other hormonal resistances, leading to overt or subclinical hypothyroidism, hypogonadism and growth hormone (GH) deficiency, impaired growth without measurable evidence for hormonal abnormalities, type 2 diabetes, and skeletal issues with potentially severe limitation of mobility. PHP and related disorders are primarily clinical diagnoses.

Hypophosphatasia mimicking hypoxic-ischaemic encephalopathy: early recognition and management.

Background: Hypophosphatasia (HPP) is a rare inherited disorder affecting bone and teeth development. Perinatal HPP is the most severe form and associated with a high mortality. Features include respiratory distress, skeletal abnormalities and low alkaline phosphatase (ALP) activity.

New Developments in the Treatment of X-Linked Hypophosphataemia: Implications for Clinical Management.

X-linked hypophosphataemia (XLH) is due to mutations in phosphate-regulating gene with homologies to endopeptidases on the X chromosome (PHEX) and represents the most common heritable form of rickets. In this condition, the hormone fibroblast growth factor 23 (FGF23) is produced in excessive amounts for still unknown reasons, and causes renal phosphate wasting and suppression of 1,25-dihydroxyvitamin D, leading to low serum phosphate concentrations. Prolonged hypophosphataemia decreases apoptosis of hypertrophic chondrocytes in growth plates (causing rickets) and decreases mineralisation of existing bone (causing osteomalacia).

Glycated haemoglobin as a screening test for abnormal glucose homeostasis in childhood obesity.

Aim: To estimate the proportion of type 2 diabetes mellitus and abnormal glucose homeostasis in childhood obesity and assess the predictive role of HbA as a diagnostic marker compared with oral glucose tolerance testing (OGTT).

Methods: A retrospective study in a tertiary paediatric hospital. Data were collected on all overweight or obese children who underwent routine OGTT between 2012 and 2016.

Tissue non-specific alkaline phosphatase activity and mineralization capacity of bi-allelic mutations from severe perinatal and asymptomatic hypophosphatasia phenotypes: Results from an in vitro mutagenesis model.

Background: Hypophosphatasia (HPP) is an inherited metabolic bone disease characterized by reduced mineralization due to mutations in the tissue non-specific alkaline phosphatase (ALPL) gene. HPP is clinically variable with extensive allelic heterogeneity in the ALPL gene. We report the findings of in vitro functional studies following site-directed mutagenesis in bi-allelic mutations causing extreme clinical phenotypes; severe perinatal and asymptomatic HPP.

Growth hormone prescribing patterns in the UK, 2013-2016.

Introduction: Prescribing of recombinant human growth hormone (rhGH) for growth failure in UK children is based on guidance from the National Institute for Health and Care Excellence. In 2013, the British Society for Paediatric Endocrinology and Diabetes initiated a national audit of newly prescribed rhGH treatment for children and adolescents. In this review, we have examined prescribing practices between 2013 and 2016.

Causes, patterns and severity of androgen excess in 487 consecutively recruited pre- and post-pubertal children.

Objective Androgen excess in childhood is a common presentation and may signify sinister underlying pathology. Data describing its patterns and severity are scarce, limiting the information available for clinical decision processes. Here, we examined the differential diagnostic value of serum DHEAS, androstenedione (A4) and testosterone in childhood androgen excess.

Healthcare resource utilization in the management of hypophosphatasia in three patients displaying a spectrum of manifestations.

Background: Hypophosphatasia (HPP) is a rare, heterogeneous disease caused by low tissue-nonspecific alkaline phosphatase activity and associated with a range of signs and symptoms, including bone mineralization defects, respiratory problems, seizures, premature tooth loss, and fractures. Data from patients with HPP and their healthcare resource utilization are lacking. We evaluated healthcare utilization for 3 patients with differing severities of HPP.

Cumulative radiation exposure from medical imaging and associated lifetime cancer risk in children with osteogenesis imperfecta.

Objectives: To estimate the cumulative effective dose of radiation (E) and additional lifetime attributable risk (LAR) of cancer from ionizing radiation in children with osteogenesis imperfecta (OI), who require frequent imaging for fractures and bone densitometry (DXA) surveillance. Also, to evaluate the pattern of long bone fractures.

Methods: We reviewed all imaging (x-rays, DXA and computed tomography [CT]) conducted in a cohort of children with OI with a minimum observation period of 5 years.