Misra, Madhusmita

Abstract Context Preclinical studies demonstrate that treatment with calcitriol attenuates skeletal complications in mice with X-linked hypophosphatemia (XLH). Objective This work aimed to assess serum markers of mineral metabolism, nephrocalcinosis, skeletal microarchitecture, growth, and evidence of rickets following calcitriol monotherapy in children and adults with XLH. Methods A 1-year, prospective, single-arm, open-label study was conducted comparing baseline and 12-month outcomes. Participants were recruited from outpatient endocrinology clinics in the United States. Data were collected in a research unit. Eligible participants were aged 4 years or older, not pregnant, with baseline 25-hydroxyvitamin D of 20 ng/mL or greater and normal serum calcium. Participants were treated with calcitriol, with dose based on serum and urinary calcium concentrations, for 1 year. The primary end points were change in serum phosphate and nephrocalcinosis (all participants) and rickets severity score (children). Secondary end points included changes in additional markers of mineral metabolism, skeletal microarchitecture parameters via high-resolution peripheral quantitative computed tomography (all participants), and height z-scores (children). Results Serum phosphate did not change over 12 months of optimized calcitriol treatment. Rickets improved in 2 of 4 children with open epiphyses; height z-scores were unchanged. Nephrocalcinosis scores remained stable. Adults had increased cortical thickness at the radius diaphysis (P = .012). Serum alkaline phosphatase decreased in children (P = .021) and parathyroid hormone trended lower both in children (P = .065) and adults (P = .063). Four participants developed mild hypercalcemia and 2 developed hypercalciuria that resolved with calcitriol titration. Conclusion Calcitriol monotherapy is safe and well-tolerated in XLH, with modest benefits on laboratory indices of mineral metabolism and rickets.

Purpose There are sparse data defining the dose response of radiation therapy (RT) to the hypothalamus and pituitary in pediatric and young adult patients with brain tumors. We examined the correlation between RT dose to these structures and development of endocrine dysfunction in this population. Materials and Methods Dosimetric and clinical data were collected from children and young adults (< 26 years of age) with brain tumors treated with proton RT on three prospective studies (2003 to 2016). Deficiencies of growth hormone (GH), thyroid hormone, adrenocorticotropic hormone, and gonadotropins were determined clinically and serologically. Incidence of deficiency was estimated using the Kaplan-Meier method. Multivariate models were constructed accounting for radiation dose and age. Results Of 222 patients in the study, 189 were evaluable by actuarial analysis, with a median follow-up of 4.4 years (range, 0.1 to 13.3 years), with 31 patients (14%) excluded from actuarial analysis for having baseline hormone deficiency and two patients (0.9%) because of lack of follow-up. One hundred thirty patients (68.8%) with medulloblastoma were treated with craniospinal irradiation (CSI) and boost; most of the remaining patients (n = 56) received involved field RT, most commonly for ependymoma (13.8%; n = 26) and low-grade glioma (7.4%; n = 14). The 4-year actuarial rate of any hormone deficiency, growth hormone, thyroid hormone, adrenocorticotropic hormone, and gonadotropin deficiencies were 48.8%, 37.4%, 20.5%, 6.9%, and 4.1%, respectively. Age at start of RT, time interval since treatment, and median dose to the combined hypothalamus and pituitary were correlated with increased incidence of deficiency. Conclusion Median hypothalamic and pituitary radiation dose, younger age, and longer follow-up time were associated with increased rates of endocrinopathy in children and young adults treated with radiotherapy for brain tumors.

AbstractObjectiveThe aim of this study was to examine the relative contributions of body mass index (BMI) and pubertal measures for risk and age of onset of pediatric MS.MethodsCase–control study of 254 (63% female) MS cases (onset<18 years of age) and 420 (49% female) controls conducted at 14 U.S. Pediatric MS Centers. Sex‐ and age‐stratified BMI percentiles were calculated using CDC growth charts from height and weight measured at enrollment for controls, and within 1 year of onset for MS cases. Sex‐stratified associations between MS risk and age at symptom onset with both BMI and pubertal factors were estimated controlling for race and ethnicity.ResultsOnly 11% of girls and 15% of boys were prepubertal (Tanner stage I) at MS onset. 80% of girls had onset of MS after menarche. BMI percentiles were higher in MS cases versus controls (girls: P < 0.001; boys: P = 0.018). BMI was associated with odds of MS in multivariate models in postpubertal girls (OR = 1.60, 95% confidence interval [CI]: 1.12, 2.27, P = 0.009) and boys (OR = 1.43, 95% CI: 1.08, 1.88, P = 0.011). In girls with MS onset after menarche, higher BMI was associated with younger age at first symptoms (P = 0.031). Younger menarche was associated with stronger effects of BMI through mediation and interaction analysis. In pubertal/postpubertal boys, 89% of whom were obese/overweight, earlier sexual maturity was associated with earlier onset of MS (P < 0.001).InterpretationHigher BMI in early adolescence is a risk factor for MS in girls and boys. Earlier age at sexual maturity contributes to earlier age at MS onset, particularly in association with obesity.