Obesity-Associated GNAS Mutations and the Melanocortin Pathway.

BACKGROUND: GNAS encodes the Gαs (stimulatory G-protein alpha subunit) protein, which mediates G protein-coupled receptor (GPCR) signaling. GNAS mutations cause developmental delay, short stature, and skeletal abnormalities in a syndrome called Albright's hereditary osteodystrophy. Because of imprinting, mutations on the maternal allele also cause obesity and hormone resistance (pseudohypoparathyroidism). METHODS: We performed exome sequencing and targeted resequencing in 2548 children who presented with severe obesity, and we unexpectedly identified 22 GNAS mutation carriers. We investigated whether the effect of GNAS mutations on melanocortin 4 receptor (MC4R) signaling explains the obesity and whether the variable clinical spectrum in patients might be explained by the results of molecular assays. RESULTS: Almost all GNAS mutations impaired MC4R signaling. A total of 6 of 11 patients who were 12 to 18 years of age had reduced growth. In these patients, mutations disrupted growth hormone-releasing hormone receptor signaling, but growth was unaffected in carriers of mutations that did not affect this signaling pathway (mean standard-deviation score for height, -0.90 vs. 0.75, respectively; P = 0.02). Only 1 of 10 patients who reached final height before or during the study had short stature. GNAS mutations that impaired thyrotropin receptor signaling were associated with developmental delay and with higher thyrotropin levels (mean [±SD], 8.4±4.7 mIU per liter) than those in 340 severely obese children who did not have GNAS mutations (3.9±2.6 mIU per liter; P = 0.004). CONCLUSIONS: Because pathogenic mutations may manifest with obesity alone, screening of children with severe obesity for GNAS deficiency may allow early diagnosis, improving clinical outcomes, and melanocortin agonists may aid in weight loss. GNAS mutations that are identified by means of unbiased genetic testing differentially affect GPCR signaling pathways that contribute to clinical heterogeneity. Monogenic diseases are clinically more variable than their classic descriptions suggest. (Funded by Wellcome and others.).

Outcome of Non-hematological Autoimmunity After Hematopoietic Cell Transplantation in Children with Primary Immunodeficiency.

PURPOSE: Knowledge of post-hematopoietic cell transplantation (HCT) non-hematological autoimmune disease (AD) is far from satisfactory. METHOD: This multicenter retrospective study focuses on incidence, risk factors, and outcomes of post-HCT AD in 596 children with primary immunodeficiency (PID) who were transplanted from 2009 to 2018. RESULTS: The indications of HCT were severe combined immunodeficiency (SCID, n = 158, 27%) and non-SCID PID (n = 438, 73%). The median age at HCT was 2.3 years (range, 0.04 to 18.3 years). The 5-year overall survival for the entire cohort was 79% (95% cumulative incidence (CIN), 74-83%). The median follow-up of surviving patients was 4.3 years (0.08 to 14.7 years). The CIN of post-HCT AD was 3% (2-5%) at 1 year post-HCT, 7% (5-11%) at 5 years post-HCT, and 11% (7-17%) at 8 years post-HCT. The median onset of post-HCT AD was 2.2 years (0.12 to 9.6 years). Autoimmune thyroid disorder (n = 19, 62%) was the most common post-HCT AD, followed by neuromuscular disorders (n = 7, 22%) and rheumatological manifestations (n = 5, 16%). All patients but one required treatment for post-HCT AD. After multivariate analysis, age at transplant (p = 0.01) and T cell-depleted graft (p < 0.001) were significant predictors of post-HCT AD. None of the T cell-depleted graft recipients developed post-HCT AD. Patients with a lower CD3+ count at 6 months post-HCT had a significant higher incidence of post-HCT AD compared to disease controls. Graft-versus-host disease, viral infection, and donor chimerism had no association with post-HCT AD. CONCLUSION: Post-HCT AD occurred in 11% at 8 years post-HCT and its occurrence was associated with older age at HCT and unmanipulated graft.

A survey of the young person's experience of Graves' disease and its management.

OBJECTIVE: A suboptimal quality of life (QoL) has been reported in patients with Graves' disease treated in adult life, but long-term QoL in those treated in childhood and adolescence is unclear. We wanted to understand how Graves' disease and its management impact on the physical, psychological and social well-being of young people and their longer-term QoL. DESIGN, PATIENTS AND MEASUREMENTS: Two questionnaires were used to assess QoL and patient experience of Graves' disease; PedsQL™ Generic Core Scales and a Graves' disease questionnaire devised for this project. The anonymized questionnaires were sent to young people (<30 years) diagnosed with Graves' disease in childhood and adolescence and managed at a tertiary paediatric endocrine unit in the North of England. Respondent QoL scores were compared with a healthy UK cohort. RESULTS: Questionnaires were sent to 51 young people, and 26 responded (51%). Graves' patients reported a lower total QoL score compared with the healthy cohort (p = .003). This was particularly apparent in the psychosocial domain (p = .0016). No patient regretted having definitive treatment (surgery/radioiodine), and all said they would recommend it to others. Half of those who had received definitive treatment still did not feel recovered. There was no difference in the long-term QoL in those who did/did not receive definitive treatment (p = .40). CONCLUSIONS: This study highlights short- and long-term impacts on the QoL and general well-being of young people with Graves' disease. There were no regrets regarding the choice of definitive treatment. This information will help inform the counselling of patients and their families.

Measurement of salivary testosterone in adolescents and young men with Duchenne muscular dystrophy.

BACKGROUND: Many young adults with Duchenne Muscular Dystrophy (DMD) receive long-term glucocorticoids (GC). GC can cause hypogonadotrophic hypogonadism and adolescents may therefore be candidates for pubertal induction. It is unclear whether men with DMD on or off GC have age-appropriate endogenous testosterone production. METHODS: We undertook a quality improvement project to assess the feasibility of measuring salivary testosterone (SalT) levels in men with DMD at home. A Sal-T sampling kit was sent by post to all patients with DMD, aged 17 and older, registered at the John Walton Muscular Centre in Newcastle (n = 75). Submitted Sal-T samples were collected and submitted for analysis. RESULTS: Twenty-eight out of seventy-five patients returned samples (age range: 17-34 years). 6/28 samples were unsuitable for analysis. Overall Sal-T levels (n = 22) were significantly lower than in the healthy population (178 ± 107 v 287 ± 109 pmol/l, p = 0.0001). Sal-T was lower in those on GC compared to those off GC (144 ± 81 versus 218 ± 125 pmol/l, p = 0.05). Three patients were unable to collect a sample due to ventilator dependence. CONCLUSION: Sal T can provide information about androgen status in DMD patients at home, overcoming barriers such as mobility difficulties and challenging venepuncture. However we only obtained samples in a minority of patients suggesting that Sal-T measurement may not be appropriate or acceptable to everyone. There needs to be a more detailed exploration of the barriers to sample submission.

DLG2 variants in patients with pubertal disorders.

PURPOSE: Impaired function of gonadotropin-releasing hormone (GnRH) neurons can cause a phenotypic spectrum ranging from delayed puberty to isolated hypogonadotropic hypogonadism (IHH). We sought to identify a new genetic etiology for these conditions. METHODS: Exome sequencing was performed in an extended family with autosomal dominant, markedly delayed puberty. The effects of the variant were studied in a GnRH neuronal cell line. Variants in the same gene were sought in a large cohort of individuals with IHH. RESULTS: We identified a rare missense variant (F900V) in DLG2 (which encodes PSD-93) that cosegregated with the delayed puberty. The variant decreased GnRH expression in vitro. PSD-93 is an anchoring protein of NMDA receptors, a type of glutamate receptor that has been implicated in the control of puberty in laboratory animals. The F900V variant impaired the interaction between PSD-93 and a known binding partner, Fyn, which phosphorylates NMDA receptors. Variants in DLG2 that also decreased GnRH expression were identified in three unrelated families with IHH. CONCLUSION: The findings indicate that variants in DLG2/PSD-93 cause autosomal dominant delayed puberty and may also contribute to IHH. The findings also suggest that the pathogenesis involves impaired NMDA receptor signaling and consequently decreased GnRH secretion.

How do paediatricians use and monitor antithyroid drugs in the UK? A clinician survey.

OBJECTIVE: We aimed to document current practice in the medical management of paediatric hyperthyroidism in the UK and compare to international recommendations. DESIGN: A 27-question online survey distributed via an electronic newsletter in August 2018. PARTICIPANTS: Responses from 48 members (11%) of the British Society for Paediatric Endocrinology and Diabetes. MEASUREMENTS: Information about antithyroid drug (ATD) preference, treatment duration, monitoring of full blood count (FBC), management of neutropaenia, agranulocytosis screening and patient education. RESULTS: Carbimazole is favoured by 98% of respondents and a "dose titration" regimen preferred over "block and replace" (65% vs 29%). TRAbs (thyroid-stimulating hormone receptor antibodies) are used for diagnostic purposes by 85% and by 33% to look for evidence of disease remission. The majority (81%) treat for a minimum of 2 years before considering a trial off ATD. All respondents reported that they "always/usually" warn their patients about the risk of agranulocytosis before starting ATD, but written information is "rarely/never" provided by 63%. Sore throat (98%) and fever (92%) are the most commonly cited symptoms used to alert a patient to possible agranulocytosis. FBC is measured prior to treatment by 65% and measured periodically during treatment by 70%. CONCLUSIONS: The management of paediatric hyperthyroidism with ATDs in the UK is not consistent with all international recommendations because a block and replace ATD regimen remains widely used. TRAbs are utilized at presentation, but underused for detecting disease remission. National consensus guidelines and written patient information may refine the management of paediatric patients on ATDs.

Analysis of BAFF gene polymorphisms in UK Graves' disease patients.

OBJECTIVE: B lymphocyte activating factor (BAFF), a member of the tumour necrosis factor superfamily, is essential for B cell activation, differentiation and survival. Elevated circulating BAFF levels have been found in patients with several autoimmune conditions, including Graves' disease. In addition, BAFF gene variants have been associated with Graves' disease in a Taiwanese cohort, and with several other autoimmune conditions in non-Taiwanese populations. DESIGN AND METHODS: We performed a case-control association study to investigate two BAFF polymorphisms (rs9514828 and rs4000607) in a UK cohort of 444 patients with Graves' disease. Genotype frequencies were compared to those from 447 local controls and more than 5000 healthy controls from the Wellcome Trust case-control consortium (WTCCC2). RESULTS: There was a significant difference in the frequency of the AA genotype at rs4000607 between the Graves' disease cohort and both the local controls (P = 0.045) and the WTCCC2 controls (P = 4.56 × 10-6 ). Furthermore, the frequency of the A allele was found to be increased in the Graves' disease group compared to WTCCC2 controls (P = 0.02, OR 1.20 (95% CI 1.03-1.41). No association was observed at the rs9514828 locus. CONCLUSION: Dysfunction of the humoral immune system is an obligatory pathophysiological component of Graves' disease, hence BAFF is an excellent functional candidate gene. We have demonstrated, for the first time, a significant association of the BAFF polymorphism rs4000607 with Graves' disease in a UK cohort. Further work to elucidate the role of BAFF in the pathogenesis of Graves' disease is now warranted.

Should we be offering fertility preservation by surgical sperm retrieval to men with Klinefelter syndrome?

Advances in surgical sperm retrieval have greatly increased the chances of men with Klinefelter syndrome achieving biological paternity. Despite this, the vast majority of attempts to achieve fertility by using extracted gametes to fertilize eggs in vitro do not result in viable pregnancies. A powerful obstacle to success lies with the natural history of seminiferous tubule and germ cell function in Klinefelter syndrome, which typically peak (and thereafter steeply decline) up to a decade before most individuals would be contemplating paternity. Herein we discuss, in relation to a real clinical case, both the exciting technical advances surgical sperm retrieval and the logistic and ethical factors that, in practice, may act to limit their successful application.

Treatment options in the young patient with Graves' disease.

The treatment options in the young patient with Graves' disease are the same as in adults, namely antithyroid drug (ATD), surgery (partial or total thyroidectomy) and radioiodine. However, the emphasis and expectation is different in the young person, reflecting a range of considerations including age, pubertal status, disease natural history, likely impact of ATD on disease course and the implications of radiation exposure. New therapeutic strategies that could increase the likelihood of long-term remission are being explored.

Prophylactic oral bisphosphonate therapy in duchenne muscular dystrophy.

INTRODUCTION: We assessed prophylactic use of bisphosphonate (BP) in Duchenne muscular dystrophy (DMD) patients on glucocorticoid (GC) therapy. METHODS: Fifty-two DMD patients on daily GC were offered BP (oral risedronate). Patients were reviewed for tolerability, side effects, bone pain, and fracture frequency. Bone mineral density (BMD) was determined by annual dual energy X-ray absorptiometry. BP-treated patients were compared with 15 BP-naïve patients (untreated cohort). RESULTS: Side effects occurred in 9 patients. Thirty-six patients continued BP therapy for over 12 months (mean, 3.6 years). Five treated patients reported bone pain. Three treated patients suffered a vertebral fracture, significantly less than in the untreated cohort (5/15). Lumbar spine adjusted BMD Z-scores remained unchanged in treated patients and were significantly greater than in the untreated cohort. CONCLUSIONS: Prophylactic oral risedronate therapy was tolerated by most DMD patients. It appears to maintain BMD and may reduce fracture rate in DMD patients on GC. Muscle Nerve 54: 79-85, 2016.

Renal and Adrenal Ultrasonography: a valuable diagnostic tool in the salt-wasting infant.

UNLABELLED: The major differential diagnosis in 'salt-wasting' infants (characterised by hyponatraemia and hyperkalaemia) is that of an adrenal or renal disorder. Appropriate management relies on rapid diagnosis, but existing guidelines do not highlight the role of ultrasonography. We describe how ultrasound may lead to a more rapid diagnosis in disorders of sex development (DSD) and other potential 'salt-wasting' infants. CONCLUSION: Ultrasonography as a diagnostic tool in infants with salt-wasting or DSD needs to be more widely recognised.

Testosterone Treatment of Pubertal Delay in Duchenne Muscular Dystrophy.

BACKGROUND: The outlook for adolescents with Duchenne muscular dystrophy (DMD) has improved greatly as a result of corticosteroid use, but treatment will compromise growth and delay puberty. Whether exogenous testosterone can promote growth, development, and skeletal health is unclear. METHODS: We collected data retrospectively on growth and pubertal response in 14 adolescents with DMD who were treated with testosterone between 2008 and 2014. RESULTS: A total of 14 boys were treated at a median age of 14.5 years. Eight have finished treatment after a mean age of 3.1 years and the feedback from families was generally positive. The mean testicular volume pretreatment was 2.4 and 3.9 mL posttreatment. The mean baseline testosterone concentrations were < 1.0 and 5.4 nmol/L postintervention. Median height velocity increased from 0.45 cm/y before treatment to 3.6 cm/y after the treatment. The mean height gain was 14.2 cm. CONCLUSIONS: A broad range of testosterone preparations was used. Testosterone was generally well-liked, but side effects were experienced by some patients and the pubertal growth increment appears to be compromised. Few subjects had adult endogenous testosterone levels posttreatment. Controlled studies are required to determine the most appropriate treatment regimen and the precise impact of testosterone on key outcomes, such as muscle function and bone integrity. Clinicians will then be better placed to advise families about likely benefits and risks.

Bones, stones, moans and groans: hypercalcaemia revisited.

Disorders of calcium homeostasis are uncommon but important because of the broad spectrum of potential underlying causes that lie on a spectrum from the benign to the life-threatening. Paediatricians may find them challenging because they do not arise often enough for the investigative approach to be second nature. We report a 4-year-old with acute onset profound hypercalcaemia. We focus on an approach to the clinical problem that is based on the potential organ systems affected, namely the gut, bone and kidney. Key biochemical parameters that may help the paediatric team to reach a diagnosis are discussed, as well as important components of acute management.

Impaired quality of life in growth hormone-deficient adults is independent of the altered skeletal muscle oxidative metabolism found in conditions with peripheral fatigue.

CONTEXT: Growth hormone-deficient (GHD) adults often report impaired quality of life (QoL) - with fatigue, a key element. This deficit can improve following GH replacement. The basis of this response is unclear. Perturbations in skeletal muscle metabolism have been demonstrated in several conditions in which fatigue is a prominent symptom. We wished to define the role of skeletal muscle metabolism in the impaired QoL observed in patients with GHD. OBJECTIVE: To compare in vivo skeletal muscle mitochondrial oxidative phosphorylation using phosphorus-31 magnetic resonance spectroscopy in matched untreated GHD adults, treated GHD adults and healthy volunteers. DESIGN: Twenty-two untreated GHD adults, 23 treated GHD adults and 20 healthy volunteers were recruited at a regional centre. All patients underwent assessment of muscle mitochondrial function (τ1/2 PCr) and proton handling using spectroscopy. Fasting biochemical analyses and anthropometric measurement were obtained. All patients completed the QoL-AGHDA and physical activity assessment (IPAQ) questionnaires. RESULTS: Untreated and treated GHD adults complained of significantly increased fatigue and an impaired QoL (P = 0·002) when compared to healthy controls. There was no difference in maximal mitochondrial function (P = 0·53) nor pH recovery (P = 0·38) of skeletal muscle between the three groups. Untreated GHD patients had significantly lower IGF-1 than both treated GHD and healthy volunteers (P < 0·001), but there was no association between τ1/2 PCr and serum IGF-1 (r = -0·13, P = 0·32). CONCLUSIONS: The impaired QoL seen in GHD adults is not associated with the skeletal muscle spectroscopic 'footprint' of altered mitochondrial oxidative function, anaerobic glycolysis or proton clearance that are a feature of several conditions in which fatigue is a prominent feature. These data suggest that the pathophysiology of fatigue and impaired QoL in GHD may have a significant central rather than peripheral (skeletal muscle) component.

National service evaluation of the quality of care for children and young people with congenital adrenal hyperplasia in the United Kingdom: survey responses from patients and clinicians.

INTRODUCTION: Quantifying differences in service provision for children and young people (CYP) living with Congenital Adrenal Hyperplasia (CAH) across the United Kingdom. METHODS: A national service evaluation using online questionnaires circulated to patients and clinicians from secondary and tertiary UK centres managing CYP with CAH, and via the "Living with CAH" support group mailing list. RESULTS: Total of 195 responses relating to patients aged 0-20 years attending 33 clinics (43 patients, 152 carers), as well as 34 clinicians from 18 trusts working across the 33 clinics. Only 12% of clinicians were 'completely satisfied' with the service provided, compared to 68% of carers and 76% of patients. Whilst 94% of clinicians reported providing formal training to families with CAH, over 80% of both patients and carers reported not attending what they considered formal training. Appetite for further training was higher in carers (86%) than patients (55%), although further 'unsure' responses suggested formal training sessions would likely be well attended. Access to psychological services was difficult for 44% of clinicians. Biochemical monitoring of treatment was broadly in keeping with international guidelines, with 67% of clinicians reporting regular use of dried blood spots, and 12% regular urinary steroid metabolites. CONCLUSION: While there is overall good satisfaction with care provision among patients and carers with CAH in the UK, extra resources addressing the psychological and educational needs about the disease and its management would benefit patients and carers. Improved access to allied health professionals and psychologists will help support families and improve patient outcomes.

Functional polymorphisms affecting the clinically important arginine-137 residue of AVPR2 do not influence serum sodium concentration at the population level.

The protein product of the AVPR2 gene, coding for the arginine vasopressin receptor type 2, is essential for vasopressin-dependent concentration of the urine. The arginine residue at position 137 in the protein product of this gene is uniquely pivotal for function. The R137H mutant inactivates the receptor conferring congenital nephrogenic diabetes insipidus, whereas activating mutations at this same residue (i.e., R137C and R137L) confer pathological water retention in the nephrogenic syndrome of inappropriate antidiuresis. These mutations were discovered in human subjects with conspicuous phenotypes in clinical water balance. Prevalence of these polymorphisms among asymptomatic individuals has not been assessed, nor has their contribution to broad interindividual variation in serum sodium concentration; no data addressing minor allele frequency are available. We genotyped two large cohorts using a validated high-throughput Pyrosequencing-based assay that we designed to capture the totality of pathological variation at this important residue. In the Osteoporotic Fractures in Men (MrOS) Study, all participants were male (i.e., hemizygous for AVPR2 gene on the X-chromosome), and participants were oversampled at the extremes of the population distribution for serum sodium concentration. In the Offspring Cohort of the Framingham Heart Study, male and female participants were genotyped. No pathological variants affecting R137 were detected among the 5,142 AVPR2 alleles successfully genotyped. Even at the population extremes of serum sodium distribution, we estimate minor allele frequency < 0.06%. We conclude that these disease-associated variants are exceedingly uncommon and do not contribute broadly to interindividual variability in serum sodium concentration or to its heritability.

What is the best approach to the teenage patient presenting with nonclassical congenital adrenal hyperplasia: should we always treat with glucocorticoids?

Patients with Congenital adrenal hyperplasia due to partial deficiency in the enzyme 21-hydroxylase can present in childhood or adolescence with signs of adrenal androgen excess. Strategies to reduce the impact of androgen excess in females include cosmetic measures as well as antiandrogens and agents such as the combined oral contraceptive pill. Glucocorticoid may not be appropriate straightaway but can be introduced if other measures are ineffective or when pregnancy is planned.