Dual X-ray absorptiometry has limited utility in detecting bone pathology in children with hypophosphatasia: A pooled post hoc analysis of asfotase alfa clinical trial data.

Asfotase alfa is an enzyme replacement therapy approved for treatment of patients with pediatric-onset hypophosphatasia (HPP), a rare, inherited, systemic disease causing impaired skeletal mineralization, short stature, and reduced physical function in children. The role of dual X-ray absorptiometry (DXA) in the assessment of children with HPP has been insufficiently explored. This post hoc analysis included pooled DXA data from 2 open-label, multicenter studies in 19 children with HPP. The study population was aged ≥5 to <18 years and had received asfotase alfa for ≤6.6 years at enrollment (male: 79%; median age at enrollment: 10.4 y [range: 5.9-16.7]; treatment duration: 6.3 y [range: 0.1-6.6]. Baseline height Z-scores indicated short stature (median [min, max]: -1.26 [-6.6, 0]); mean [SD]: -2.30 [1.97]), thus requiring height adjustment of DXA Z-scores. At Baseline, few patients had height-adjusted bone mineral density (BMDht) Z-scores of -2 or less for whole body (n = 3) or lumbar spine (n = 5). In treated patients, mean whole body and lumbar spine BMDhtZ-scores did not change over time, but whole body and lumbar spine height- adjusted bone mineral content (BMCht) Z-scores increased significantly from Baseline to Last Assessment (P ≤ 0.0056). Improvements in Radiographic Global Impression of Change (RGI-C) scale scores correlated significantly with increases in whole body and lumbar spine BMChtZ-scores (P < 0.05) but not BMDhtZ-Scores. Improvements in Rickets Severity Score (RSS) correlated significantly with increases in lumbar spine BMDhtZ-scores and whole body BMCht Z-scores (P < 0.05). No significant correlations were observed between any DXA and bone histomorphometry measure. These findings suggest that DXA BMD Z-scores, which are commonly used in clinical practice, have limited utility in assessing deficient bone mineralization in patients with HPP. Although BMChtZ-scores increased significantly over time with asfotase alfa therapy, the lack of significant changes in more than one DXA parameter suggests that this tool may not be useful in everyday clinical practice. Furthermore, the use of BMC as an independent metric is not typical or recommended by guidelines. Complementary measures, such as skeletal radiographs supplemented with age-appropriate functional assessments, should be considered.

Short-Term PTH(1-34) Therapy in Children to Correct Severe Hypocalcemia and Hyperphosphatemia due to Hypoparathyroidism: Two Case Studies.

The standard treatment of hypoparathyroidism is to control hypocalcemia using calcitriol and calcium supplementation. However, in severe cases this approach is insufficient, and the risks of intravenous (i.v.) calcium administration and prolonged hospitalization must be considered. While the use of recombinant human parathyroid hormone 1-34 [rhPTH(1-34)] for long-term control of hypocalcemia has been established, the benefits of short-term rhPTH(1-34) treatment in children have not been explored. We report two patients with hypoparathyroidism treated with rhPTH(1-34). Patient 1 is a 10-year-old female with polyglandular autoimmune syndrome type 1. Patient 2 is a 12-year-old female with hypoparathyroidism after total thyroidectomy. Both patients showed poor response to i.v. and oral calcium and calcitriol, and patient 1 did not respond to phosphate binders. Patient 1 had rapid increase in serum calcium with a decrease in serum phosphate after a 3-day course of subcutaneous rhPTH(1-34). Patient 2 had normalization of calcium and phosphate levels after a 7-day course of rhPTH(1-34). These cases support a role for rhPTH(1-34) in the acute management of hypoparathyroidism in hospitalized patients to more rapidly correct hypocalcemia and hyperphosphatemia, shorten hospitalization, and reduce the need for frequent i.v. calcium boluses.

Endocrine disorders in Fanconi anemia: recommendations for screening and treatment.

CONTEXT: Endocrine problems are common in patients with Fanconi anemia (FA). About 80% of children and adults with FA have at least one endocrine abnormality, including short stature, GH deficiency, abnormal glucose or insulin metabolism, dyslipidemia, hypothyroidism, pubertal delay, hypogonadism, or impaired fertility. The goal of this report is to provide an overview of endocrine abnormalities and guidelines for routine screening and treatment to allow early diagnosis and timely intervention. EVIDENCE ACQUISITION: This work is based on a comprehensive literature review, including relevant articles published between 1971 and 2014, and proceedings of a Consensus Conference held by the Fanconi Anemia Research Fund in 2013. EVIDENCE SYNTHESIS: The panel of experts collected published evidence and discussed its relevance to reflect current information about the endocrine care of children and adults with FA before the Consensus Conference and through subsequent deliberations that led to the consensus. CONCLUSIONS: Individuals with FA should be routinely screened for endocrine abnormalities, including evaluation of growth; glucose, insulin, and lipid metabolism; thyroid function; puberty; gonadal function; and bone mineral metabolism. Inclusion of an endocrinologist as part of the multidisciplinary patient care team is key to providing comprehensive care for patients with FA.

Maternal diet supplementation with methyl donors and increased parity affect the incidence of craniofacial defects in the offspring of twisted gastrulation mutant mice.

Diets rich in methyl-donating compounds, including folate, can provide protection against neural tube defects, but their role in preventing craniofacial defects is less clear. Mice deficient in Twisted gastrulation (TWSG1), an extracellular modulator of bone morphogenetic protein signaling, manifest both midline facial defects and jaw defects, allowing study of the effects of methyl donors on various craniofacial defects in an experimentally tractable animal model. The goal of this study was to examine the effects of maternal dietary supplementation with methyl donors on the incidence and type of craniofacial defects among Twsg1(-/-) offspring. Nulliparous and primiparous female mice were fed an NIH31 standard diet (control) or a methyl donor supplemented (MDS) diet (folate, vitamin B-12, betaine, and choline). Observed defects in the pups were divided into those derived mostly from the first branchial arch (BA1) (micrognathia, agnathia, cleft palate) and midline facial defects in the holoprosencephaly spectrum (cyclopia, proboscis, and anterior truncation). In the first pregnancy, offspring of mice fed the MDS diet had lower incidence of BA1-derived defects (12.8% in MDS vs. 32.5% in control; P = 0.02) but similar incidence of midline facial defects (6.4% in MDS vs. 5.2% in control; P = 1.0). Increased maternal parity was independently associated with increased incidence of craniofacial defects after adjusting for diet (from 37.7 to 59.5% in control, P = 0.04 and from 19.1 to 45.3% in MDS, P = 0.045). In conclusion, methyl donor supplementation shows protective effects against jaw defects, but not midline facial defects, and increased parity can be a risk factor for some craniofacial defects.

NCI, NHLBI/PBMTC first international conference on late effects after pediatric hematopoietic cell transplantation: endocrine challenges-thyroid dysfunction, growth impairment, bone health, & reproductive risks.

The endocrine system is highly susceptible to damage by high-dose chemotherapy and/or irradiation before hematopoietic cell transplantation (HCT) during childhood. The specific endocrine organs most affected by HCT include the thyroid gland, the pituitary, and the gonads. In addition, hormones that support development and stability of the skeletal system are also affected. Insufficiency of thyroid hormone is 1 of the most common late sequelae of HCT, and occurs more often in young children. Deficiency in the pituitary's production of growth hormone is a problem of unique concern to the pediatric population. The reproductive risks of HCT depend on the patient's gender and pubertal status at the time of HCT. Pubertal or gonadal failure frequently occurs, especially in females. Infertility risks for both genders remain high, whereas methods of fertility preservation are limited in all but postpubertal males. Bone health post-HCT can be compromised by low bone mineral density as well as avascular necrosis, but the data on both problems in the pediatric HCT population are limited. In this paper, the current state of knowledge, gaps in that knowledge, and recommendations for future research are addressed in detail for each of these systems.

Hippocampus specific iron deficiency alters competition and cooperation between developing memory systems.

UNLABELLED: Iron deficiency (ID) is the most common gestational micronutrient deficiency in the world, targets the fetal hippocampus and striatum and results in long-term behavioral abnormalities. These structures primarily mediate spatial and procedural memory, respectively, in the rodent but have interconnections that result in competition or cooperation during cognitive tasks. We determined whether ID-induced impairment of one alters the function of the other by genetically inducing a 40% reduction of hippocampus iron content in late fetal life in mice and measuring dorsal striatal gene expression and metabolism and the behavioral balance between the two memory systems in adulthood. Slc11a2(hipp/hipp) mice had similar striatum iron content, but 18% lower glucose and 44% lower lactate levels, a 30% higher phosphocreatine:creatine ratio, and reduced iron transporter gene expression compared to wild type (WT) littermates, implying reduced striatal metabolic function. Slc11a2(hipp/hipp) mice had longer mean escape times on a cued task paradigm implying impaired procedural memory. Nevertheless, when hippocampal and striatal memory systems were placed in competition using a Morris Water Maze task that alternates spatial navigation and visual cued responses during training, and forces a choice between hippocampal and striatal strategies during probe trials, Slc11a2(hipp/hipp) mice used the hippocampus-dependent response less often (25%) and the visual cued response more often (75%) compared to WT littermates that used both strategies approximately equally. Hippocampal ID not only reduces spatial recognition memory performance but also affects systems that support procedural memory, suggesting an altered balance between memory systems. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s11689-010-9049-0) contains supplementary material, which is available to authorized users.

The use of hormonal therapy in pediatric heart disease.

The endocrine system plays an intricate role in the regulation and modulation of cardiovascular function. Several hormones including thyroid, mineralocorticoid, glucocorticoid, arginine-vasopressin (AVP), and growth hormone (GH) have been investigated as adjunctive therapies in pediatric cardiac disease. Thyroid hormone supplementation appears to be safe in neonatal and pediatric post-operative cardiac patients, but the benefits have been modest and inconsistent. Glucocorticoids appear to decrease the inflammatory response associated with cardiopulmonary bypass in children, but have little effect on clinical outcomes. The role of AVP in pediatric shock remains limited due to inconsistent trial results and its potential side effect profile. Although mineralcorticoids are commonly used to treat neurocardiogenic syncope, little to no benefit has been demonstrated in controlled trials. GH normalizes altered cardiac function in children who are GH deficient, but its effectiveness in the treatment of heart failure has been variable. Overall, the use of these hormones in a variety of pediatric cardiac conditions generally appears to be safe, but their efficacy for relieving symptoms, improving cardiac function, and improving clinical outcomes remains unclear.

Vitamin D deficiency in children and its management: review of current knowledge and recommendations.

Given the recent spate of reports of vitamin D deficiency, there is a need to reexamine our understanding of natural and other sources of vitamin D, as well as mechanisms whereby vitamin D synthesis and intake can be optimized. This state-of-the-art report from the Drug and Therapeutics Committee of the Lawson Wilkins Pediatric Endocrine Society was aimed to perform this task and also reviews recommendations for sun exposure and vitamin D intake and possible caveats associated with these recommendations.