Disease Manifestations and Complications in Dutch X-Linked Hypophosphatemia Patients.

X-linked hypophosphatemia (XLH) is the most common monogenetic cause of chronic hypophosphatemia, characterized by rickets and osteomalacia. Disease manifestations and treatment of XLH patients in the Netherlands are currently unknown. Characteristics of XLH patients participating in the Dutch observational registry for genetic hypophosphatemia and acquired renal phosphate wasting were analyzed. Eighty XLH patients, including 29 children, were included. Genetic testing, performed in 78.8% of patients, showed a PHEX mutation in 96.8%. Median (range) Z-score for height was - 2.5 (- 5.5; 1.0) in adults and - 1.4 (- 3.7; 1.0) in children. Many patients were overweight or obese: 64.3% of adults and 37.0% of children. All children received XLH-related medication e.g., active vitamin D, phosphate supplementation or burosumab, while 8 adults used no medication. Lower age at start of XLH-related treatment was associated with higher height at inclusion. Hearing loss was reported in 6.9% of children and 31.4% of adults. Knee deformities were observed in 75.0% of all patients and osteoarthritis in 51.0% of adult patients. Nephrocalcinosis was observed in 62.1% of children and 33.3% of adults. Earlier start of XLH-related treatment was associated with higher risk of nephrocalcinosis and detection at younger age. Hyperparathyroidism longer than six months was reported in 37.9% of children and 35.3% of adults. This nationwide study confirms the high prevalence of adiposity, hearing loss, bone deformities, osteoarthritis, nephrocalcinosis and hyperparathyroidism in Dutch XLH patients. Early start of XLH-related treatment appears to be beneficial for longitudinal growth but may increase development of nephrocalcinosis.

Colibactin mutational signatures in NTHL1 tumor syndrome and MUTYH associated polyposis patients.

Polyketide synthase (pks) island harboring Escherichia coli are, under the right circumstances, able to produce the genotoxin colibactin. Colibactin is a risk factor for the development of colorectal cancer and associated with mutational signatures SBS88 and ID18. This study explores colibactin-associated mutational signatures in biallelic NTHL1 and MUTYH patients. Targeted Next Generation Sequencing (NGS) was performed on colorectal adenomas and carcinomas of one biallelic NTHL and 12 biallelic MUTYH patients. Additional fecal metagenomics and genome sequencing followed by mutational signature analysis was conducted for the NTHL1 patient. Targeted NGS of the NTHL1 patient showed somatic APC variants fitting SBS88 which was confirmed using WGS. Furthermore, fecal metagenomics revealed pks genes. Also, in 1 out of 11 MUTYH patient a somatic variant was detected fitting SBS88. This report shows that colibactin may influence development of colorectal neoplasms in predisposed patients.

Body mass index at diagnosis of a childhood brain tumor; a reflection of hypothalamic-pituitary dysfunction or lifestyle?

PURPOSE: Childhood brain tumor survivors (CBTS) are at risk of becoming overweight, which has been shown to be associated with hypothalamic-pituitary (HP) dysfunction during follow-up. Body mass index (BMI) at diagnosis is related to BMI at follow-up. It is uncertain, however, whether aberrant BMI at brain tumor diagnosis reflects early hypothalamic dysfunction or rather reflects genetic and sociodemographic characteristics. We aimed to examine whether BMI at childhood brain tumor diagnosis is associated with HP dysfunction at diagnosis or its development during follow-up. METHODS: The association of BMI at diagnosis of a childhood brain tumor to HP dysfunction at diagnosis or during follow-up was examined in a Dutch cohort of 685 CBTS, excluding children with craniopharyngioma or a pituitary tumor. Individual patient data were retrospectively extracted from patient charts. RESULTS: Of 685 CTBS, 4.7% were underweight, 14.2% were overweight, and 3.8% were obese at diagnosis. Being overweight or obese at diagnosis was not associated with anterior pituitary deficiency or diabetes insipidus at diagnosis or during follow-up. In children with suprasellar tumors, being obese at diagnosis was associated with central precocious puberty. CONCLUSION: Overweight or obesity at diagnosis of a childhood brain tumor seems not to be associated with pituitary deficiencies. These results suggest that genetics and lifestyle may be more important etiologic factors for higher BMI at diagnosis in these children than hypothalamic dysfunction. To improve the long-term outcome of CBTS with regards to overweight and obesity, more attention should be given to lifestyle already at the time of brain tumor treatment.

Prevalence and risk factors of hypothalamic-pituitary dysfunction in infant and toddler childhood brain tumor survivors.

OBJECTIVE: Childhood brain tumor survivors (CBTS) are at risk to develop hypothalamic-pituitary (HP) dysfunction (HPD). The risk for HPD may vary between different age groups due to maturation of the brain and differences in oncologic treatment protocols. Specific studies on HPD in infant brain tumor survivors (infant-BTS, 0-1 years at diagnosis) or toddler brain tumor survivors (toddler-BTS, ≥1-3 years) have not been performed. PATIENTS AND METHODS: A retrospective nationwide cohort study in CBTS was performed. Prevalence and risk factors for HPD were compared between infant-, toddler-, and older-BTS. Subgroup analysis was performed for all non-irradiated CBTS (n = 460). RESULTS: In total, 718 CBTS were included, with a median follow-up time of 7.9 years. Overall, despite the less frequent use of radiotherapy (RT) in infants, no differences in the prevalence of HPD were found between the three groups. RT (OR: 16.44; 95% CI: 8.93-30.27), suprasellar tumor location (OR: 44.76; 95% CI: 19.00-105.49), and younger age (OR: 1.11; 95% CI: 1.05-1.18) were associated with HP dysfunction. Infant-BTS and toddler-BTS showed more weight gain (P < 0.0001) and smaller height SDS (P = 0.001) during follow-up. In non-irradiated CBTS, infant-BTS and toddler-BTS were significantly more frequently diagnosed with TSH-, ACTH-, and ADH deficiency, compared to older-BTS. CONCLUSION: Infant and toddler brain tumor survivors seem to be more vulnerable to develop HP dysfunction than older children. These results emphasize the importance of special infant and toddler brain tumor treatment protocols and the need for endocrine surveillance in children treated for a brain tumor at a young age.

Management and consequences of postoperative fluctuations in plasma sodium concentration after pediatric brain tumor surgery in the sellar region: a national cohort analysis.

PURPOSE: Severe fluctuations in plasma sodium concentration and plasma osmolarity, including central diabetes insipidus (CDI), may have significant influence on postoperative morbidity and mortality after pediatric brain tumor surgery.The aim of this study was to describe the frequency, severity and neurological consequences of these fluctuations in pediatric brain tumor survivors. METHODS: A retrospective, multi-institutional chart review was conducted among all children who underwent brain tumor surgery in the sellar or suprasellar region in seven university hospitals in the Netherlands between January 2004 and December 2013. RESULTS: Postoperative CDI was observed in 67.5% of 120 included children. Fluctuations of plasma sodium concentration ≥ 10 mmol/L/24 h during the first ten postoperative days were seen in 75.3% of patients with CDI, with a maximum delta of 46 mmol/L/24 h. When compared to patients without CDI, altered mental status occurred more frequently in patients with postoperative CDI (5.1 vs. 23.5% respectively, p = 0.009). Low plasma sodium concentration was related to altered mental status and the occurrence of seizures. Frequency and severity of fluctuations in plasma sodium concentration during the first ten postoperative days were significantly higher in patients with permanent CDI at last follow-up than in patients with transient CDI or without CDI (p = 0.007). CONCLUSION: Postoperative CDI is a common complication after pediatric brain tumor surgery in the sellar or suprasellar region. Extreme plasma sodium concentrations and large intra-day fluctuations still occur and seem to influence the postoperative neurological course. These results illustrate the need for intensive monitoring in a highly experienced center.

Bone mineral density after childhood cancer in 346 long-term adult survivors of childhood cancer.

SUMMARY: More than 45 % of long-term childhood cancer survivors (CCS) were diagnosed with osteopenia. Our data suggest that greater awareness for osteopenia is warranted in long-term CCS, especially in survivors who are older than 30 years, male, and underweight and were treated with cranial-spinal radiotherapy and/or steroids. INTRODUCTION: Osteopenia is a potential complication of childhood cancer treatment, but the magnitude of this problem in survivors is unknown. We examined (determinants of) bone mineral density (BMD) status in long-term survivors of adult childhood cancer. METHODS: This retrospective single-centre cohort study included 346 subjects with the most common types of childhood cancer. Subjects had a median age at diagnosis of 7.0 years (range 0.1-16.8 years), a median age at follow-up of 24.5 years (range 18.0-47.6 years) and a median follow-up time of 16.7 years (range 5.6-39.9 years). Total body BMD (BMDTB) and BMD of the lumbar spine (BMDLS) were measured by dual X-ray absorptiometry. Osteopenia was defined as BMD standardized deviation score (SDS) below -1. RESULTS: Survivors had a lower BMDTB and BMDLS (mean SDS -0.55; p<0.001 and -0.30; p<0.001, respectively) as compared to healthy peers. Osteopenia (BMDTB and/or BMDLS) was present in 45% of the survivors. Multivariate logistic regression analyses identified age at diagnosis<12 years, age>30 years at follow-up, male gender, underweight at follow-up and treatment with cranial-spinal radiotherapy or prednisone as independent prognostic factors for osteopenia. CONCLUSIONS: This large cohort of childhood cancer survivors identified osteopenia in 45% of CCS. This indicates that greater awareness is warranted, especially in survivors who are older than 30 years, male, have underweight and were treated with cranial-spinal radiotherapy and/or steroids.

Fertility of tall girls treated with high-dose estrogen, a dose-response relationship.

CONTEXT: High-dose estrogen treatment to reduce final height of tall girls increases their risk for infertility in later life. OBJECTIVE: The aim was to study the effect of estrogen dose on fertility outcome of these women. DESIGN/SETTING: We conducted a retrospective cohort study of university hospital patients. PATIENTS: We studied 125 tall women aged 20-42 yr, of whom 52 women had been treated with 100 µg and 43 with 200 µg of ethinyl estradiol (EE) in adolescence. MAIN OUTCOMES: Time to first pregnancy, treatment for infertility, and live birth rate were measured. RESULTS: The time to first pregnancy was increased in treated women. Of untreated women, 80% conceived within 1 yr vs. 69% of women treated with 100 µg EE and 59% of women treated with 200 µg EE. This trend of increased time to pregnancy with increasing estrogen dose was significant (log rank trend test, P = 0.01). Compared with untreated women, fecundability was reduced in women treated with both 100 µg EE [hazard ratio = 0.42; 95% confidence interval (CI), 0.19-0.95] and 200 µg EE (hazard ratio = 0.30; 95% CI, 0.13-0.72). We also observed a significant trend in the incidence of treatment for infertility with increased estrogen dose (P = 0.04). Fecundity was affected in women treated with 200 µg EE who had reduced odds of achieving at least one live birth (odds ratio = 0.13; 95% CI, 0.02-0.81), but not in women treated with 100 µg EE. CONCLUSIONS: We report a dose-response relationship between fertility in later life and estrogen dose used for the treatment of tall stature in adolescent girls; a higher estrogen dose is associated with increased infertility.

A rare cause of facial nerve palsy in children: hyperostosis corticalis generalisata (Van Buchem disease). Three new pediatric cases and a literature review.

Differential diagnosis of facial nerve palsy in children is extensive. We report on three pediatric cases presenting with facial nerve palsy caused by hyperostosis corticalis generalisata (Van Buchem disease). This autosomal recessive disease is characterized by progressive bone overgrowth, with narrowing of the neuroforamina in the skull causing cranial neuropathies. These three new cases of Van Buchem disease are of interest because of exceptionally early presentation of symptoms. Furthermore, this is the first report describing bilateral papilledema in a child with Van Buchem disease. Head computerized tomography (CT) scan revealed thickened calvarium, skull base and mandible in all three children, with narrowed facial nerve canals. Bone mineral density (BMD) was markedly increased at all measured points and biochemical markers of bone formation were significantly elevated. Diagnosis of Van Buchem disease was genetically confirmed. The cases are unique in that these are the first well-documented pediatric cases of Van Buchem disease.

Genetic variation in candidate genes like the HMGA2 gene in the extremely tall.

BACKGROUND/AIMS: Genetic variation in several candidate genes has been associated with short stature. Recently, a high-mobility group A2 (HMGA2) gene SNP has been robustly associated with height in the general population. Only few have attempted to study these genes in extremely tall stature. We therefore studied common genetic variation in candidate genes for height in extremely tall Dutch. METHODS: We included 116 constitutionally tall cases with height >2 SD and 103 controls with normally distributed height <2 SD. We genotyped 10 common polymorphisms previously associated with height variation. RESULTS: The HMGA2 gene SNP was significantly associated with tall stature. Using a logistic regression model, we calculated that carrying the HMGA2 (rs1042725) C allele significantly increased the odds of being tall (OR = 1.53, 95% CI 1.02-2.28; p = 0.03). In addition, controls with one or two copies of the C allele were significantly taller than controls carrying the TT genotype [TC: mean (SD) +0.61 (0.21) SDS; p = 0.004, and CC: +0.77 (0.25) SDS; p = 0.003]. CONCLUSION: Our study shows that a common polymorphism in the HMGA2 gene is not only associated with height variation in the general population but also plays an important role in one of the extremes of the height distribution.

Common polymorphisms in the GH/IGF-1 axis contribute to growth in extremely tall subjects.

CONTEXT/OBJECTIVE: The growth hormone (GH)/insulin-like growth factor-1(IGF-1) axis is the key regulator of somatic growth in humans and its genes are plausible candidates to study the genetics of height variation. Here, we studied polymorphic variation in the GH/IGF-1 axis in the extremely tall Dutch. METHODS: Case-control study of 166 tall cases with height >2 SDS and 206 controls with normally distributed height <2 SDS. Excluded were subjects with endocrine disorders or growth syndromes. We analyzed genomic DNA at 7 common polymorphisms in the GH-1, GH receptor (GHR), IGF-1 and IGFBP-3 genes. RESULTS: The association of the GH-1 1663 SNP with tall stature approached statistical significance, with the T-allele more present in the tall (allele frequency (AF): 0.44 vs. 0.36; p=0.084). Moreover, haplotype frequencies at this locus were significantly different between cases and controls, with the GGT haplotype most commonly seen in cases (p=0.01). Allele frequencies of GHR polymorphisms were not different. For the IGF-1 CA-repeat we observed a higher frequency of homozygous 192-bp carriers among tall males compared to control males (AF: 0.62 vs. 0.55; p=0.02). The IGFBP-3 -202 C-allele occurred more frequently in cases than in controls (AF: 0.58 vs. 0.50; p=0.002). Within cases, those carrying one or two copies of the -202 C-allele were significantly taller than AA genotype carriers (AC, p=0.028 and CC, p=0.009). Serum IGFBP-3 levels were highest in AA genotype carriers, the -202 SNP explained 5.8% of the variation. CONCLUSION: Polymorphic variation in the GH-1, IGF-1 and IGFBP-3 genes is associated with extremely tall stature. In particular, the IGFBP-3 -202 SNP is associated not only with being very tall but also with height variation within the tall.

Fertility and ovarian function in high-dose estrogen-treated tall women.

BACKGROUND/OBJECTIVE: High-dose estrogen treatment to reduce final height of tall girls has been shown to interfere with fertility. Ovarian function has not been studied. We therefore evaluated fertility and ovarian function in tall women who did or did not receive such treatment in adolescence. METHODS: This was a retrospective cohort study of 413 tall women aged 23-48 yr, of whom 239 women had been treated. A separate group of 126 fertile, normoovulatory volunteers aged 22-47 yr served as controls. RESULTS: Fertility was assessed in 285 tall women (157 treated, 128 untreated) who had attempted to conceive. After adjustment for age, treated women were at increased risk of experiencing subfertility [odds ratio (OR) 2.29, 95% confidence interval (CI) 1.38-3.81] and receiving infertility treatments (OR 3.44, 95% CI 1.76-6.73). Moreover, fecundity was notably affected because treated women had significantly reduced odds of achieving at least one live birth (OR 0.26, 95% CI 0.13-0.52). Remarkably, duration of treatment was correlated with time to pregnancy (r = 0.23, P = 0.008). Ovarian function was assessed in 174 tall women (119 treated, 55 untreated). Thirty-nine women (23%) exhibited a hypergonadotropic profile. After adjusting for age category, treated women had significantly higher odds of being diagnosed with imminent ovarian failure (OR 2.83, 95% CI 1.04-7.68). Serum FSH levels in these women were significantly increased, whereas antral follicle counts and serum anti-Müllerian hormone levels were decreased. CONCLUSION: High-dose estrogen-treated tall women are at risk of subfertility in later life. Their fecundity is significantly reduced. Treated women exhibit signs of accelerated ovarian aging with concomitant follicle pool depletion, which may be the basis of the observed subfertility.

Fatherhood in tall men treated with high-dose sex steroids during adolescence.

BACKGROUND/OBJECTIVE: Sex steroid treatment to reduce final height of tall boys has been available since the 1950s. In women, it has been shown to interfere with fertility. In men, no such data are available. We therefore evaluated fertility and gonadal function in tall men who did or did not receive high-dose androgen treatment in adolescence. METHODS: We conducted a retrospective cohort study of 116 tall men, of whom 60 had been treated. Reproductive and gonadal function was assessed by standardized interview, semen analysis, endocrine parameters, ultrasound imaging, and fatherhood. Mean age at treatment commencement was 14.2 yr, and mean follow-up was 21.2 yr. RESULTS: Sixty-six men (36 treated and 30 untreated) had attempted to achieve fatherhood. The probability of conceiving their first pregnancy within 1 yr was similar in treated and untreated men (26 vs. 24; Breslow P=0.8). Eleven treated and 13 untreated men presented with a left-sided varicocele (P=0.5). Testicular volume, sperm quality, and serum LH, FSH, and inhibin B levels were comparable between treated and untreated men. However, treated men had significantly reduced serum T levels, adjusted for known confounders [mean (sd) 13.3 (1.8) vs. 15.2 (1.9) nmol/liter; P=0.005). In addition, testicular volume and serum inhibin B and FSH levels in treated men were significantly correlated with age at treatment commencement. CONCLUSION: At a mean follow-up of 21 yr after high-dose androgen treatment, we conclude that fatherhood and semen quality in tall treated men are not affected. Serum testosterone levels, however, are reduced in androgen-treated men. Future research is required to determine whether declining testosterone levels may become clinically relevant for these men as they age.

Influence of birth size and body composition on bone mineral density in early adulthood: the PROGRAM study.

BACKGROUND/OBJECTIVES: Low bone mineral density (BMD) may lead to osteoporosis and is associated with increased fracture risk. Associations between BMD and various factors have been reported. Our objective was to investigate whether birth size, lean body mass (LBM) and fat mass (FM) are determinants of BMD of the total body (BMD(TB)) and the lumbar spine (BMD(LS)). METHODS: In the PROgramming factors for GRowth And Metabolism (PROGRAM) study of a cohort of 312 young adults aged 18-24 years, BMD(TB) and BMD(LS) were determined by dual-energy X-ray absorptiometry (DXA). Subsequently, differences in BMD(TB) and BMD(LS) were analysed in four subgroups: young adults born small for gestational age with short stature (SGA-S) or with catch-up growth (SGA-CU), or born appropriate for gestational age (AGA) with idiopathic short stature (ISS) or with normal stature (controls). RESULTS: Adult weight, LBM, FM and weight gain during childhood were the main positive determinants for BMD(TB) in early adulthood, whereas birth size had no influence (adjusted R(2) = 0.50). Gender, adult weight, LBM, FM and weight gain were the significant determinants of BMD(LS). In the subgroups, after correction for age, gender and adult body size, the ISS group had a significantly lower BMD(TB) than controls but there was no difference in BMD(LS) between the subgroups. CONCLUSIONS: Prenatal growth has no significant influence on BMD(TB) and BMD(LS) in early adulthood. Gender and postnatal growth, particularly weight gain, are the main positive determinants. To achieve a normal BMD in adulthood, healthcare workers should aim for a normal weight gain in children.

[Seizures in foreign newborns due to maternal vitamin-D deficiency]. / Convulsies bij allochtone pasgeborenen door hypovitaminose D bij de moeder.

In a Moroccan male, a Turkish female and a Sudanese male newborn who presented with seizures in the second week of life, hypocalcaemia was found. The hypocalcaemia was caused by neonatal vitamin-D deficiency as a result of maternal vitamin-D deficiency during pregnancy. The vitamin-D deficiency of the mothers was caused by the diminished exposure to sunlight as a result of wearing a veil and the dark pigmentation of the skin. The infants were cured by vitamin-D suppletion. With the increasing numbers of dark-skinned women and women who wear veils in the Dutch population, the group of pregnant women and newborns running a risk of vitamin-D deficiency is becoming larger. Therefore, the risk of hypocalcaemia and vitamin-D deficiency rickets in newborns is also increasing. In newborns with seizures, one should think of the possibility of neonatal vitamin-D deficiency, especially if the mothers belong to the group at risk.

Estrogen receptor alpha gene polymorphisms and bone mineral density in healthy children and young adults.

The accretion of peak bone mass is largely under genetic control, and one of the potential candidate genes is the estrogen receptor alpha (ERalpha) gene. The association of ERalpha gene polymorphisms with bone mineral density (BMD) was investigated in a group of 147 healthy caucasian children, adolescents, and young adults (57 boys and 90 girls) in a cross-sectional and longitudinal study. The mean age was 11.3 years (4.3-19.9 years) at baseline and 15.6 years (7.6-25.3 years) at follow-up. Lumbar spine, total body BMD, and body composition were measured by dual energy X-ray absorptiometry and expressed as age- and sex-adjusted standard deviation scores (SDS). We analyzed two restriction fragment length polymorphisms, Pvull and Xbal, and haplotypes thereof. Subjects homozygous for haplotype 1 (px) (33% of the population) had 0.4 SD (standard deviation) lower lumbar spine BMD (P = 0.02) and bone mineral apparent density (BMAD) (P = 0.04) than those heterozygous or noncarriers for haplotype 1 (px) at baseline. Analysis of the follow-up data gave similar results. The association was stronger for the prepubertal than for the postpubertal subjects. Vertebral width SDS, total body BMD SDS, height SDS, body mass index SDS, lean body mass SDS, and percentage fat SDS did not significantly differ between the haplotypes. The age of menarche was not related to any of the haplotypes in girls. The present study shows that Pvull-Xbal ERalpha gene polymorphism is associated with BMD during childhood.

Digital radiogrammetry of the hand in a pediatric and adolescent Dutch Caucasian population: normative data and measurements in children with inflammatory bowel disease and juvenile chronic arthritis.

We have evaluated the applicability of a new Digital X-ray Radiogrammetry (DXR) system in a Dutch Caucasian pediatric population. For this study we enrolled 535 healthy participants who all signed an informed consent form. In addition, 20 children suffering from inflammatory bowel disease (IBD) and juvenile chronic arthritis (JCA) were enrolled. Radiographs of the left hand were obtained from all participants. From the healthy population a subset of children with a history of forearm fractures were separately analyzed. Measurements consisted of DXR (X-posure; Pronosco-Sectra, Linköping, Sweden). Five hundred thirty-five subjects were enrolled in the study. Twenty-two subjects (4.3%) were discontinued (age 3-10 years), all because of a nonrecognizable radiograph by the DXR system. The short-term coefficient of variation of DXR in this population was 0.59%. Significant differences in DXR-BMD between boys and girls for the ages of 11, 12, 16, 17, and 18 years were found. There were also significant differences in DXR-BMD between the sequential Tanner stages. For 88 subjects repeat radiographs were available (mean interval 1.8 years). In all cases an increase in DXR-BMD was seen. Girls with IBD, JCA, or a history of forearm fractures and boys with IBD showed a significantly lower DXR-BMD compared with healthy controls. We show that DXR is an applicable technique in children. Also, in a small subpopulation it is possible to discriminate children with a high risk of low BMD.

Reference data for bone density and body composition measured with dual energy x ray absorptiometry in white children and young adults.

AIMS: To obtain normative data on bone mineral density and body composition measured with dual energy x ray absorptiometry (DXA) from early childhood to young adulthood. METHODS: Cross sectional results from 444 healthy white volunteers (4-20 years) in the Netherlands were combined with the results from 198 children who agreed to participate in the follow up study approximately four years later. DXA (Lunar, DPXL) of lumbar spine and total body was performed to assess bone density and body composition. RESULTS: Bone density and lean body mass (LBM) increased with age. Maximal increase in bone density and LBM occurred around the age of 13 years in girls and approximately two years later in boys. Bone density of total body and lumbar spine showed an ongoing slight increase in the third decade. Mean fat percentage in boys remained at 10.5% throughout childhood, but increased in girls. CONCLUSIONS: Most of the skeletal mass in lumbar spine and total body is reached before the end of the second decade, with a slight increase thereafter. This study provides reference values for bone density and body composition measured with DXA for children and young adults.

Bone density and body composition in chronic renal failure: effects of growth hormone treatment.

Metabolic bone disease and growth retardation are common complications of chronic renal failure (CRF). We evaluated bone mineral density (BMD), bone metabolism, body composition and growth in children with CRF, and the effect of growth hormone treatment (GHRx) on these variables. Thirty-three prepubertal patients with CRF were enrolled including 18 children with growth retardation, who were treated with growth hormone for 2 years. Every 6 months, BMD of lumbar spine and total body, and body composition were measured by dual-energy X-ray absorptiometry. Biochemical parameters of bone turnover were assessed. Mean BMD of children with CRF did not differ from normal. During GHRx, BMD and bone mineral apparent density of lumbar spine and height SDS increased, whereas BMD of total body did not change. Lean body mass increased in the GH group. Alkaline phosphatase increased significantly in the GH group only. The other biochemical parameters of bone turnover increased in both groups, none of them correlated with the changes in BMD. No serious adverse effects of GHRx were reported. In conclusion, BMD of children with CRF did not differ from healthy children. Adequate treatment with alpha-calcidiol or the short duration of renal failure may have attributed to the absence of osteopenia in our patients. BMD of the axial skeleton and growth improved with GHRx.

Bone mineral density in children with acute lymphoblastic leukaemia.

Bone mineral density (BMD) may be negatively affected by the disease or its treatment in patients with acute lymphoblastic leukaemia (ALL). Therefore, we evaluated lumbar spine and total body BMD and bone metabolism in children with ALL at diagnosis, during treatment with chemotherapy and 1 year after completion of treatment. 32 children (21 boys and 11 girls) participated in the study. 14 children started the study at diagnosis and 18 during or after the treatment period. Lumbar spine and total body BMD were measured with dual energy X-ray absorptiometry, and expressed as standard deviation scores (SDS). Blood samples were obtained to assess bone metabolism. 3 of 14 children had low lumbar spine BMD (< -2 S.D.) at diagnosis. All children had normal total body BMD. Markers of bone turnover were depressed. Total body BMD SDS decreased significantly during the first year of treatment (P < 0.001). Lumbar spine BMD SDS did not change significantly. Parameters of bone turnover increased to normal during the treatment period. Parathyroid hormone had increased significantly after 1 year (P < 0.05). Mineral homeostasis was disturbed in some patients during treatment. 4 of 9 patients had low total body BMD and 1 patient low lumbar spine BMD one year after completion of treatment. All patients had normal biochemical results at that time. In conclusion, lumbar spine BMD and bone turnover were decreased in some patients at diagnosis. Total body BMD decreased significantly during treatment and was low in 4 of the 9 patients 1 year after completion of the treatment.