Zeynep Şıklar

Zinc deficiency: a contributing factor of short stature in growth hormone deficient children

Zinc is an essential trace element which affects growth by promoting DNA and RNA synthesis and cell division. Zinc deficiency causes growth retardation and its frequency is high in developing countries. It could contribute to the effect of growth hormone (GH) treatment in GH deficient children. In this study, we investigated zinc deficiency in GH children. Twenty-four GH deficient children (treated with GH for 2.2 +/- 1.6 years) were recruited for the study. Intracellular erythrocyte zinc levels were measured. Eleven (45.9 per cent) were found to be zinc deficient (Group 1), while 13 patients (54.1 per cent) had normal zinc levels (Group 2). The mean growth velocity was 5.98 +/- 0.8 cm/year in Group 1 and 6.9 +/- 1.4 cm/year in Group 2. Group 2 was given oral zinc supplementation with a resultant growth velocity of 7.51 +/- 0.5 cm/year. During GH treatment in GH deficient children, zinc status should be evaluated as severe zinc deficiency could affect the response to GH treatment.

Relationships Between Osteocalcin, Glucose Metabolism, and Adiponectin in Obese Children: Is there Crosstalk Between Bone Tissue and Glucose Metabolism?

Objective: Recently, scientific interest has focused on the association between osteocalcin, which originates from the skeletal system, and glucose metabolism. Although the association between lipid metabolism, adiponectin, and metabolic syndrome is well known, that between obesity, insulin resistance, and osteocalcin have not been clarified yet in children. The aim of this study was to assess the prevalence of insulin resistance in obese children and adolescents, as well as to investigate the effects of adiponectin and osteocalcin on the development of metabolic syndrome and insulin resistance. Methods: A total of 150 obese nondiabetic children and adolescents, aged between 5 and 18 years, were included in the study. Serum adiponectin, osteocalcin and insulin levels were measured, and the association of the components of metabolic syndrome with adiponectin and osteocalcin levels was investigated. Insulin resistance was evaluated by Homeostasis model assessment insulin resistance (HOMA-IR). Results: Metabolic syndrome was identified in 28% of the cases, all older than 10 years of age. No significant association was identified between insulin resistance, metabolic syndrome parameters, and osteocalcin levels. Adiponectin levels were significantly low in cases with metabolic syndrome, hyperinsulinemia, and in those with dyslipidemia. No significant association was found between adiponectin and osteocalcin levels. Conclusions: We failed to show the effect of osteocalcin on insulin resistance in obese children and adolescents. This finding may be due to absence of hypergycemic blood glucose levels in our cases. Conflict of interest:None declared.

Distribution of gene mutations associated with familial normosmic idiopathic hypogonadotropic hypogonadism.

Objective: Normosmic idiopathic hypogonadotropic hypogonadism (nIHH) is characterized by failure of initiation or maintenance of puberty due to insufficient gonadotropin release, which is not associated with anosmia/hyposmia. The objective of this study was to determine the distribution of causative mutations in a hereditary form of nIHH. Methods: In this prospective collaborative study, 22 families with more than one affected individual (i.e. multiplex families) with nIHH were recruited and screened for genes known or suspected to be strong candidates for nIHH. Results: Mutations were identified in five genes (GNRHR, TACR3, TAC3, KISS1R, and KISS1) in 77% of families with autosomal recessively inherited nIHH. GNRHR and TACR3 mutations were the most common two causative mutations occurring with about equal frequency. Conclusions: Mutations in these five genes account for about three quarters of the causative mutations in nIHH families with more than one affected individual. This frequency is significantly greater than the previously reported rates in all inclusive (familial plus sporadic) cohorts. GNRHR and TACR3 should be the first two genes to be screened for diagnostic purposes. Identification of causative mutations in the remaining families will shed light on the regulation of puberty. Conflict of interest:None declared.

The clinical and genetic heterogeneity of mixed gonadal dysgenesis: does “disorders of sexual development (DSD)” classification based on new Chicago consensus cover all sex chromosome DSD?

Clinical findings illustrate the wide spectrum of the phenotypic manifestations of 45,X/46,XY mosaicism in the sex chromosome disorders of sex differentiation (DSD). The objective of study is to evaluate the characteristics of 45,X/46,XY patients and questioning of their place within the DSD categorization. The clinical findings of 11 patients with 45,X/46,XY mosaicism are described including the presentation, gonadal morphology, genital anatomy, and the hormone levels among 285 patients with DSD evaluated. Sixty-seven patients were diagnosed with sex chromosome DSD (50 Turner, three Klinefelter, ten 45,X/46,XY gonadal disgenesis, one 45X/46,XY ovotesticular DSD, one 47,XYY ovotesticular DSD, and two 46,XX/46,XY ovotesticular DSD). The type and the percentage of patients with 45,X/46,XY mosaicism were as follows: Four cases of mix gonadal dysgenesis, four cases of partial gonadal dysgenesis, two cases of complete gonadal dysgenesis, one case of ovotesticular DSD. On the other hand, another patient that has 45,X/46,XX mosaicism was diagnosed with MGD with the presence of the streak gonad on the right side and the testis on the other side. Conclusion: We suggest that sex chromosome DSD categorization can include 45,X/46,XY PGD and 45,X/46,XY CGD. Mixed gonadal dysgenesis may be also placed among the disorders of testicular differentiation of 46,XY DSD subdivision.

Spondyloocular Syndrome – Novel Mutations in XYLT2 Gene and Expansion of the Phenotypic Spectrum

Spondyloocular syndrome is an autosomal‐recessive disorder with spinal compression fractures, osteoporosis, and cataract. Mutations in XYLT2, encoding isoform of xylosyltransferase, were recently identified as the cause of the syndrome. We report on 4 patients, 2 unrelated patients and 2 siblings, with spondyloocular syndrome and novel mutations in XYLT2. Exome sequencing revealed a homozygous nonsense mutation, NM_022167.3(XYLT2): c.2188C>T, resulting in a premature stop codon (p.Arg730*) in a female patient. The patient presents visual impairment, generalized osteoporosis, short stature with short trunk, spinal compression fractures, and increased intervertebral disc space and hearing loss. We extended our XYLT2 analysis to a cohort of 22 patients with generalized osteoporosis, mostly from consanguineous families. In this cohort, we found by Sanger sequencing 2 siblings and 1 single patient who were homozygous for missense mutations in the XYLT2 gene (p.Arg563Gly and p.Leu605Pro). The patients had osteoporosis, compression fractures, cataracts, and hearing loss. Bisphosphonate treatment in 1 patient resulted in almost complete normalization of vertebral structures by adolescence, whereas treatment response in the others was variable. This report together with a previous study shows that mutations in the XYLT2 gene result in a variable phenotype dominated by spinal osteoporosis, cataract, and hearing loss.

Clinical characteristics of recessive and dominant congenital hyperinsulinism due to mutation(s) in the ABCC8/KCNJ11 genes encoding the ATP-sensitive potasium channel in the pancreatic beta cell

Abstract Background: Recessive mutations in ABCC8/KCNJ11 of β-cell KATP channel generally cause severe medically unresponsive hyperinsulinemic hypoglycemia (HH). Rarer dominant mutations in these genes have been described that mostly cause milder, medically responsive congenital hyperinsulinism. Rarer dominant mutations in these genes have been described that mostly cause milder, medically responsive congenital hyperinsulinism. To date the phenotype of patients with dominant mutations seems to be different from those with recessive mutations as the majority of patients are responsive to diazoxide therapy. Controversy exists on whether these dominant ABCC8 or KCNJ11 genes mutations predispose to diabetes mellitus in adulthood or not. Subjects: We report the clinical and genetic characteristics of five patients with neonatal HH, three had recessively inherited KATP channel mutations and two with a dominantly acting mutation. As a result of failure to medical therapy, patients with recessive KATP channel mutations underwent a near total pancreatectomy. Two siblings with a novel dominant mutation showed good response to medical treatment. Although the HH remitted in early infancy, they became diabetic at the prepubertal age. Their mother, maternal aunt and maternal grandfather had the same mutation without any medical history of neonatal HH. Conclusion: The clinical presentation of our two patients with a dominant ABCC8 mutation was milder than that of patients with the resessive form of the disease as they responded well to medical management.

Transient neonatal diabetes with two novel mutations in the KCNJ11 gene and response to sulfonylurea treatment in a preterm infant.

Abstract Neonatal diabetes mellitus (NDM) is a rare condition that can be either transient or permanent. KATP channel (Kir6.2 or SUR1) mutation, chromosome 6 abnormalities, insulin, or glucokinase gene mutations can lead to isolated NDM. Cases caused by Kir6.2 mutation usually result in permanent NDM (PNDM) rather than transient NDM (TNDM). The majority of patients with the Kir6.2 or SUR1 mutation can be successfully managed with a sulfonylurea agent, without the need for insulin. We report a preterm male with NDM having two novel missense mutations, E322A and D352H, in the KCNJ11 gene. At 2 months of age, successful transition from insulin to glibenclamide (glyburide) therapy of the patient was managed. At 5 months of age, his diabetes went in to remission.

Evaluation of hypercoagulability in obese children with thrombin generation test and microparticle release: effect of metabolic parameters.

Obesity is associated with a hypercoagulable state. Thrombin generation test (TGT) and microparticle levels were not studied in obese children extensively. It is aimed to determine whether any differences in the coagulation system between obese and normal weighed children exist with the use of TGT and microparticles release. A total of 120 obese and 38 healthy children were included to the study. An increase of thrombin generation and microparticles levels were found in obese children. Hyperinsulinism could not find a risk factor for hypercoagulability in our obese children. None of the parameters of TGT has been shown to be related to metabolic parameters and metabolic syndrome. Microparticles release time is found to correlate only to body mass index (BMI) Standard deviation score (SDS) in obese children. Hypercoagulability is associated with childhood obesity. Significant correlation between degree of obesity and microparticles release suggested that high adipokine levels secreted from adipose tissue can stimulate procoagulant status-independent metabolic dearrangements.

Syndromic disorders with short stature.

Short stature is one of the major components of many dysmorphic syndromes. Growth failure may be due to a wide variety of mechanisms, either related to the growth hormone (GH)/insulin-like growth factor axis or to underlying unknown pathologies. In this review, the relatively more frequently seen syndromes with short stature (Noonan syndrome, Prader-Willi syndrome, Silver-Russell syndrome and Aarskog-Scott syndrome) were discussed. These disorders are associated with a number of endocrinopathies, as well as with developmental, systemic and behavioral issues. At present, GH therapy is used in most syndromic disorders, although long-term studies evaluating this treatment are insufficient and some controversies exist with regard to GH dose, optimal age to begin therapy and adverse effects. Before starting GH treatment, patients with syndromic disorders should be evaluated extensively.

The exon 3-deleted/full-length growth hormone receptor polymorphism and response to growth hormone therapy in growth hormone deficiency and Turner syndrome: a multicenter study.

Background/Aim: The exon 3-deleted/full-length (d3/fl) growth hormone (GH) receptor (GHR) polymorphism has been associated with responsiveness to GH therapy in some diagnostic groups. However, there are still controversies on this issue. To evaluate the effect of the GHR exon 3 polymorphism on growth after 1 and 2 years of GH therapy in Turkish patients with GH deficiency (GHD) and Turner’s syndrome (TS) and the distribution of GHR exon 3 isoforms. Materials and Methods: 218 patients with GHD (125 males/93 females) and 43 patients with TS were included in the study. The control group included 477 healthy adults aged from 18 to 57 years (54 females/423 males). Anthropometric parameters and insulin-like growth factor (IGF)-1 and IGF binding protein (IGFBP)-3 were evaluated annually. GHR isoforms were studied using simple multiplex PCR. Height and body mass index were expressed as standard deviation score (SDS). Results: There were no differences among TS, GHD and healthy adults regarding the distribution of GHR exon 3 isoforms (fl/fl, fl/d3 and d3/d3). There was a significant increase in height SDS in both diagnostic groups on GH therapy; however, there were neither differences in height SDS and Δheight velocity between fl/fl, fl/d3 and d3/d3 groups nor a correlation between the distribution of GHR exon 3 isoforms and change in IGF-1 SDS and IGFBP-3 SDS levels on GH therapy in either of the diagnostic groups. There was also no gender difference in GHR isoforms in healthy adults. Conclusion: The results suggest that responsiveness to GH therapy does not depend on the exon 3 GHR genotypes in GHD and TS patients.