A Rare Cause of Hypophosphatemia: Raine Syndrome Changing Clinical Features with Age.

Raine Syndrome (RS) is caused by biallelic loss-of-function mutations in FAM20C gene and characterized by hypophosphatemia, typical facial and skeletal features. Subperiosteal bone formation and generalized osteosclerosis are the most common radiological findings. Here we present a new case with RS. A 9-month-old male patient on a home-type ventilator was referred for hypophosphatemia. He was born with a weight of 3800 g to non-consanguineous parents. Prenatal ultrasound had demonstrated nasal bone agenesis. A large anterior fontanel, frontal bossing, exophthalmos, hypoplastic nose, high arched palate, low set ears, triangular mouth, and corneal opacification were detected on physical examination. Serial skeletal X-rays revealed diffuse osteosclerosis at birth which was gradually decreased by the age of 5 months with subperiosteal undermineralized bone formation and medullary space of long bone could be distinguishable with bone-within-a-bone appearance. At 9 months of age, hand X-ray revealed cupping of the ulna with loose radial bone margin with minimal fraying and osteopenia. Cranial computed tomography scan showed bilateral periventricular calcification and hydrocephalus in progress. The clinical, laboratory, and radiological examinations were consistent with RS. Molecular analyses revealed a compound heterozygous mutation in FAM20C gene (a known pathogenic mutation, c.1645C > T, p.Arg549Trp; and a novel c.863 + 5 G > C variant). The patient died due to respiratory failure at 17 months of age. This case allowed us to demonstrate natural progression of skeletal features in RS. Furthermore, we have described a novel FAM20C variant causing RS. Previous literature on RS is also reviewed.

Vitamin D Status Across Age Groups in Turkey: Results of 108,742 Samples from a Single Laboratory

Objective: The aim was to determine vitamin D status in the general population in Turkey between 2011 and 2016, and to evaluate the effectiveness of the national vitamin D supplementation programme. Methods: Serum 25-hydroxyvitamin D (25-OHD) measurement data were retrieved from an internationally accredited laboratory, operating nationwide. A total of 108,742 measurements of 25-OHD were analyzed using the cut-off values of 0-11 ng/mL, 12-19 ng/mL, 20-49 ng/mL, 50-70 ng/mL and >70 ng/mL for vitamin D deficiency, insufficiency, sufficiency, possibly harmful and excess respectively. Results: The mean±standard deviation 25-OHD level was 21.6±13.3 ng/mL. Mean 25-OHD concentrations by age groups were: 37.3 ng/mL, 30.1 ng/mL and 23.7 ng/mL for <1, 1-10 and 11-18 year old groups, respectively. Mean 25-OHD levels of children <1 year and 1-3 years of age were significantly higher than those found in other age groups. The prevalence of vitamin D deficiency (<12 ng/mL) was lowest in children at 1-3 years of age (5%). In subjects older than 18 years of age, mean 25-OHD levels were 18.2 ng/mL, 20.1 ng/mL, 21.9 ng/mL and 21.1 ng/mL for age groups 19-30, 31-50, 51-70 and >70 years, respectively. Conclusion: Successful implementation of the national vitamin D supplementation programme, appears to have nearly eliminated vitamin D deficiency for children under 1-years of age. However, the positive impact of the vitamin D supplementation diminishes as children get older suggesting that supplementation may be required in the older children and adults. In addition, improved awareness of the benefits and risks of excess vitamin D should prevent unnecessary and excessive use of vitamin D supplements.

Comparison of Treatment Regimens in Management of Severe Hypercalcemia Due to Vitamin D Intoxication in Children

Objective: No large study has been conducted to date to compare the effectiveness of prednisolone, alendronate and pamidronate as first-line treatment in children with hypercalcemia due to vitamin D intoxication. The aim was to perform a multicenter, retrospective study assessing clinical characteristics and treatment results. Methods: A standard questionnaire was uploaded to an online national database system to collect data on children with hypercalcemia (serum calcium level >10.5 mg/dL) due to vitamin D intoxication [serum 25-hydroxyvitamin D (25(OH)D) level >150 ng/mL] who were treated in pediatric endocrinology clinics. Results: Seventy-four children [median (range) age 1.06 (0.65-1.60) years, 45 males (61%) from 11 centers] were included. High-dose vitamin D intake was evident in 77% of the cases. At diagnosis, serum calcium, phosphorus, alkaline phosphatase, 25(OH)D and parathyroid hormone concentrations were 15±3.2 mg/dL, 5.2±1.2 mg/dL, 268±132 IU/L, 322 (236-454) ng/mL, and 5.5 (3-10.5) pg/mL, respectively. Calcium levels showed moderate correlation with 25(OH)D levels (rs=0.402, p<0.001). Patients were designated into five groups according to the initial specific treatment regimens (hydration-only, prednisolone, alendronate, pamidronate, and combination). Need for another type of specific drug treatment was higher in children who initially received prednisolone (p<0.001). Recurrence rate of hypercalcemia was significantly lower in children who were treated with pamidronate (p=0.02). Conclusion: Prednisolone is less effective in the treatment of children with severe hypercalcaemia secondary to vitamin D intoxication and timely implementation of other treatment regimens should be considered.

Hypothalamic obesity in children: pathophysiology to clinical management.

Hypothalamic obesity (HyOb) is a complex neuroendocrine disorder caused by damage to the hypothalamus, which results in disruption of energy regulation. The key hypothalamic areas of energy regulation are the ARC (arcuate nucleus), the VMH (ventromedial hypothalamus), the PVN (paraventriculer nuclei) and the LHA (lateral hypothalamic area). These pathways can be disrupted mechanically by hypothalamic tumors, neurosurgery, inflammatory disorders, radiotherapy and trauma or functionally as such seen in genetic diseases. Rapid weight gain and severe obesity are the most striking features of HyOb and caused by hyperphagia, reduced basal metabolic rate (BMR) and decreased physical activity. HyOb is usually unresponsive to diet and exercise. Although, GLP-1 and its anologs seem to be a new agent, there is still no curative treatment. Thus, prevention is of prime importance and the clinicians should be alert and vigilant in patients at risk for development of HyOb.

Novel homozygous inactivating mutation of the calcium-sensing receptor gene (CASR) in neonatal severe hyperparathyroidism-lack of effect of cinacalcet.

BACKGROUND: NSHPT is a life-threatening disorder caused by homozygous inactivating calcium-sensing receptor (CASR) mutations. In some cases, the CaSR allosteric activator, cinacalcet, may reduce serum PTH and calcium levels, but surgery is the treatment of choice. OBJECTIVE: To describe a case of NSHPT unresponsive to cinacalcet. PATIENT AND RESULTS: A 23-day-old girl was admitted with hypercalcemia, hypotonia, bell-shaped chest and respiratory distress. The parents were first-degree cousins once removed. Serum Ca was 4.75 mmol/l (N: 2.10-2.62), P: 0.83 mmol/l (1.55-2.64), PTH: 1096 pg/ml (9-52) and urinary Ca/Cr ratio: 0.5mg/mg. First, calcitonin was given (10 IU/kg × 4/day), and then 2 days later, pamidronate (0.5mg/kg) for 2 days. Doses of cinacalcet were given daily from day 28 of life starting at 30 mg/m2 and increasing to 90 mg/m2 on day 43. On day 33, 6 days after pamidronate, serum Ca levels had fallen to 2.5 mmol/l but, thereafter, rose to 5 mmol/l despite the cinacalcet. Total parathyroidectomy was performed at day 45. Hungry bone disease after surgery required daily Ca replacement and calcitriol for 18 days. At 3 months, the girl was mildly hypercalcemic, with no supplementation, and at 6 months, she developed hypocalcemia and has since been maintained on Ca and calcitriol. By CASR mutation analysis, the infant was homozygous and both parents heterozygous for a deletion-frameshift mutation. CONCLUSION: The predicted nonfunctional CaSR is consistent with lack of response to cinacalcet, but total parathyroidectomy was successful. An empiric trial of the drug and/or prompt mutation testing should help minimize the period of unnecessary pharmacotherapy.

Vitamin D intoxication.

Vitamin D intoxication (VDI) may result from supplementation rarely, but it has been reported more frequently in recent years. This may be attributable to an increase in vitamin D supplement intake due to an understanding of the role of vitamin D (25OHD) in the pathogenesis of several diseases. The symptoms and findings associated with VDI are closely related to serum calcium concentration and duration of hypercalcemia. In patients with VDI, hypercalcemia, normal or high serum phosphorus levels, normal or low levels of alkaline phosphatase (ALP), high levels of serum 25OHD, low serum parathyroid hormone (PTH), and high urine calcium/creatinine are usually present. Serum 25OHD levels above 150 ng/ml are considered as VDI. The main goal of treatment for VDI is correction of the hypercalcemia. When the calcium concentration exceeds 14 mg/dl, emergency intervention is necessary because of the adverse effects of hypercalcemia on cardiac, central nervous system, renal, and gastrointestinal functions. However, since vitamin D is stored in fat tissues, effects of toxicity may last for months despite the removal of the exogenous source of vitamin D. Treatment for VDI includes: discontinuation of intake, a diet with low calcium and phosphorus content, intravenous hydration with saline, loop diuretics, glucocorticoids, calcitonin, and bisphosphonates. In conclusion, the diagnosis of vitamin D deficiency rickets (VDDR) without checking serum 25OHD level may cause redundant treatment that leads to VDI. All patients who are clinically suspected of VDDR should be checked for serum vitamin D status and questioned for previous vitamin D administration before starting vitamin D therapy. On the other hand, parents of all infants should be asked whether they are using dietary or oral supplements, and serial questioning may be required during supplementation to avoid excessive intake.

The role of leptin, soluble leptin receptor, resistin, and insulin secretory dynamics in the pathogenesis of hypothalamic obesity in children.

INTRODUCTION: In this study, we have investigated the role of leptin, soluble leptin receptor(sOb-R), resistin, and insulin secretory dynamics in the development of hypothalamic obesity. MATERIALS AND METHODS: Children who had hypothalamo-pituitary tumor were divided into two groups. First group included obese-overweight (hypothalamic obese = HOB group, n = 23) and second group included non-obese children (hypothalamic non-obese = HNOB group, n = 16). Exogenously obese-overweight children (OB group, n = 22) were included as controls. Basal and second-hour serum glucose and insulin in oral glucose tolerance test (OGTT), basal serum leptin, sOb-R, resistin levels, and homeostasis model assessment (HOMA) indexes were compared between the groups. RESULTS: Age, sex, and pubertal status were similar in study groups. Median and interquartile ranges of body mass index (BMI) z scores were similar in HOB and OB groups (2.0 (1.5-2.1) and 2.1 (1.8-2.3), respectively). Serum leptin levels corrected for BMI were highest and total leptin/sOb-R ratios (free leptin index (FLI)) tended to be higher in HOB than HNOB and OB groups, indicating leptin resistance (leptin/BMI, 4.0 (1.6-5.2), 1.5 (0.8-3.1), and 2.5 (1.8-3.5); FLI, 2.0 (0.8-3.5), 0.6 (0.3-1.2), and 1.5 (1-2.3) in HOB, HNOB, and OB groups; respectively). Serum resistin levels were similar in groups (2.6 (1.9-3.1), 2.8 (1.7-3.4), and 3.0 (2.2-3.5) ng/ml in HOB, HNOB, and OB groups, respectively). Basal serum glucose, basal and second-hour insulin levels in OGTT, and HOMA index were higher in OB group than the HOB and HNOB groups, indicating insulin resistance in simple obesity; however, increment of insulin to same glycemic load in OGTT was highest in the HOB group indicating insulin dysregulation (p < 0.05). CONCLUSION: Hypothalamic obesity seems to be related to both dysregulated afferent (leptin) and efferent (insulin) neural outputs through the autonomic nervous system resulting in energy storage as fat.

Alendronate treatment in children with osteogenesis imperfecta.

BACKGROUND: Recent studies reported beneficial effect of cyclical intravenous administration of pamidronate in children and adolescents with osteogenesis imperfecta (OI). However, this treatment requires frequent hospital admissions and is relatively expensive. Alendronate is an oral bisphosphonate effectively used in adults with osteoporosis. Experience with alendronate treatment in children with OI is limited. AIMS: To report our experience with alendronate in children with OI. METHODS: 12 children with OI (7 with type I, 4 with type III and 1 with type IV; 7 boys, 5 girls) aged 1.8 to 15.4 years (7.9+/-; 4.4 yrs) were included in this retrospective study. The patients were treated with alendronate in a dose of 5-10 mg/day along with calcium (500 mg/day) and vitamin D (400-1000 IU/day) supplements for 19.8+/-11.3 months (range: 7-46 months). Serum calcium (Ca), phosphorus (P), alkaline phosphatase (ALP), osteocalcin (OC), pyrilinks-D and urinary Ca/Cr ratio were studied 3 monthly and bone mineral density (BMD) by DXA on 6-12 monthly basis. RESULTS: Fracture rate of the patients significantly decreased after treatment (1.2+/-1.5 vs. 0.16+/-0.32 per year, P<0.05). Treatment improved bone density in each individual case. Z-scores of lumbar DXA (L2-L4) significantly increased during treatment (-4.60+/-1.30 vs - 2.47+/-1.52, P< 0.05). Urinary pyrilinks-D decreased with treatment (90.8+/-136.3 vs. 35.1+/-29.9, P< 0.05). Serum Ca, P, ALP, OC and urinary Ca/Cr did not change significantly during treatment. CONCLUSION: We conclude that alendronate is effective, safe and practical alternative to intravenous bisphosphonates in treatment of children with OI.

Quantitative ultrasound and biochemical parameters for the assessment of osteopenia in preterm infants.

OBJECTIVE: Our study aimed to evaluate the feasibility of quantitative ultrasound (QUS) evaluation in osteopenia of prematurity and to compare the results to biochemical parameters. METHODS: QUS assessment of bone was performed at the end of the first postnatal week and at term-corrected age (CA) in premature infants (N = 30) and within the first week in full-term infants (N = 25). On the same day of measurement of QUS, the serum calcium, phosphorus (inorganic), and alkaline phosphatase (ALP) activity were measured in the preterm infants. RESULTS: The median of tibia z score at term-CA in premature infants was significantly lower compared to that of first postnatal week (-1 and 0.4, respectively; p < 0.0001) and it was also lower than that of term-matched controls (0.0; p = 0.001). Preterm infants at term-CA had lower weights and lengths in comparison to term infants. The median ALP value was 585 IU/L at the first postnatal week and 703 IU/L at term-CA in preterm infants (p = 0.003). The median tibia z score of infants with ALP >or=900 IU/L was significantly lower than that of the infants with ALP <900 IU/L (-1.4 vs. 0.1; p = 0.001). An inverse correlation was found between ALP levels and tibia z score at term-CA in preterm infants (rho = -0.61, p = 0.01). CONCLUSIONS: Bone density of preterm infants at term-CA was lower than that at first postnatal week. Serum ALP levels increased during the first postnatal weeks. The tibia z scores were correlated to serum ALP levels. QUS is a good screening tool for the detection of osteopenia.

The effect of the mode of delivery on neonatal thyroid function.

BACKGROUND: We aimed to investigate the effect of the mode of delivery and the type of anesthesia on postnatal thyroxine (T4), free T4 (f-T4) and thyroid-stimulating hormone (TSH) in a large number of healthy full-term neonates. METHODS: Serum samples for T4, TSH and f-T4 were drawn from neonates at the time of discharge (postnatal days 1-7) in a pilot thyroid-screening program. Six hundred and thirty-eight neonates were grouped as: vaginal delivery (VD; 332), elective cesarean section (elective C/S; 252) and emergency cesarean section (emergency C/S; 54). The elective C/S group was subdivided into local and general anesthesia groups to investigate the influence of the type of anesthesia used on thyroid function. RESULTS: Mean+/-SD serum T4, TSH and f-T4 levels tended to be higher in the VD group compared to the elective C/S group at almost all time points. However the differences did not reach statistical significance, except for the T4 levels at postnatal day 3 in the VD group, which was higher (195.6+/-37.3 nmol/L) compared to the elective C/S group (160.9+/-34.8 nmol/L) (p < 0.001). The only difference in the anesthesia groups was the slightly higher f-T4 levels from postnatal day 4 in the local anesthesia group compared to the general anesthesia group. CONCLUSIONS: The mode of delivery or type of anesthesia does not have considerable influence on postnatal thyroid functions in the neonates, although minor differences exist. Therefore similar cut-off values can be used for thyroid screening of term newborns regardless of the mode of delivery or type of anesthesia used.

Effect of zinc supplementation on growth hormone secretion, IGF-I, IGFBP-3, somatomedin generation, alkaline phosphatase, osteocalcin and growth in prepubertal children with idiopathic short stature.

Controversy exists about the effect of zinc on growth and the GH-IGF system. Zinc supplementation has been shown to stimulate linear growth in zinc-deficient children. However the mechanism of this effect has not been well characterized. Furthermore, the effect of zinc supplementation on non-zinc-deficient short children is unknown. We investigated the effect of zinc supplementation on endogenous GH secretion, serum IGF-I and IGFBP-3 concentrations, IGF-I and IGFBP-3 generation in response to exogenous GH, bone formation markers, and linear growth of non-zinc-deficient children with idiopathic short stature. We analyzed prospectively serum zinc, IGF-I, IGFBP-3, alkaline phosphatase, osteocalcin, and GH response to clonidine test, and performed a somatomedin generation test before and 6 weeks after zinc supplementation in 22 (16 M, 6 F) prepubertal children with idiopathic short stature. Serum IGF-I increased from 67.4+/-70.6 to 98.2+/-77.3 ng/ml (p <0.001), IGFBP-3 from 2326+/-770 to 2758+/-826 ng/ml (p <0.001), alkaline phosphatase from 525+/-136 to 666+/-197 U/l (p <0.0001), and osteocalcin from 16.8+/-10.6 to 25.8+/-12.8 ng/ml (p <0.05) after zinc supplementation despite there being no difference in GH response to clonidine after zinc supplementation (peak GH 11.6+/-6.9 vs 13.4+/-7.8 ng/ml, GH area under the curve during clonidine test 689+/-395 vs 761+/-468, NS). Percent change in IGF-I and IGFBP-3 during the somatomedin generation test was not significantly affected by zinc supplementation (118% vs 136% and 57% vs 44%, respectively). There was no significant correlation between percentage increase in zinc levels and percentage increase in parameters tested. Height SDS or weight SDS did not improve significantly in 17 patients who continued on zinc supplementation for at least 6 months (6-12 months) (-2.59 vs -2.53 SDS and -1.80 vs -1.67 SDS, respectively). Zinc supplementation increased basal IGF-I, IGFBP-3, alkaline phosphatase and osteocalcin without changing GH response to clonidine. Zinc supplementation did not affect sensitivity to exogenous GH as tested by IGF-I and IGFBP-3 generation test. These results suggest a direct stimulatory effect of zinc on serum IGF-IGFBP-3, alkaline phosphatase and osteocalcin. Despite improvements in the above parameters, zinc supplementation to children with idiopathic short stature with normal serum zinc levels did not significantly change height or weight SDS during 6-12 months follow-up.