Browsing by Author "Aycan, Zehra"

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Comparison of treatment regimens in management of severe hypercalcemia due to vitamin D intoxication in children
(Galenos Publ House, 2018-10-23) Demir, Korcan; Döneray, Hakan; Kara, Cengiz; Atay, Zeynep; Çetinkaya, Semra Çaǧlar; Çayır, Atilla; Anık, Ahmet; Uçaktürk, Seyit Ahmet; Yılmaz, Gülay Can; Ergür, Ayça Törel; Kendirci, Mustafa; Aycan, Zehra; Bereket, Abdullah; Aydın, Murat; Orbak, Zerrin; Özkan, Behzat; Eren, Erdal; Uludağ Üniversitesi/Tıp Fakültesi/Çocuk Endokrinolojisi Anabilim Dalı.; 0000-0002-1684-1053; AAM-1734-2020; 36113153400
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 II 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 (r(s) = 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 <0.000). 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.
Comprehensive screening of eight known causative genes in congenital hypothyroidism with gland-in-situ
(Endocrine Society, 2016-08-09) Nicholas, Adeline K.; Serra, Eva G.; Cangül, Hakan; Alyaarubi, Saif; Ullah, Irfan; Schoenmakers, Erik; Deeb, Asma; Habeb, Abdelhadi M.; Almaghamsi, Mohammad; Peters, Catherine; Nathwani, Nisha; Aycan, Zehra; Bober, Ece; Dattani, Mehul; Shenoy, Savitha; Murray, Philip G.; Babiker, Amir; Willemsen, Ruben; Thankamony, Ajay; Lyons, Greta; Irwin, Rachael; Padidela, Raja; Tharian, Kavitha; Davies, Justin H.; Puthi, Vijith; Park, Soo-Mi; Massoud, Ahmed F.; Gregory, John W.; Albanese, Assunta; Pease-Gevers, Evelien; Martin, Howard; Brugger, Kim; Maher, Eamonn R.; Chatterjee, V. Krishna K.; Anderson, Carl A.; Schoenmakers, Nadia; Sağlam, Halil; Uludağ Üniversitesi/Tıp Fakültesi/Çocuk Sağlığı ve Hastalıkları Anabilim Dalı.; 0000-0003-0710-5422; C-7392-2019; 35612700100
Context: Lower TSH screening cutoffs have doubled the ascertainment of congenital hypothyroidism (CH), particularly cases with a eutopically located gland-in-situ (GIS). Although mutations in known dyshormonogenesis genes or TSHR underlie some cases of CH with GIS, systematic screening of these eight genes has not previously been undertaken. Objective: Our objective was to evaluate the contribution and molecular spectrum of mutations in eight known causative genes (TG, TPO, DUOX2, DUOXA2, SLC5A5, SLC26A4, IYD, and TSHR) in CH cases with GIS. Patients, Design, and Setting:We screened 49 CH cases with GIS from 34 ethnically diverse families, using next-generation sequencing. Pathogenicity of novel mutations was assessed in silica. Results: Twenty-nine cases harbored likely disease-causing mutations. Monogenic defects (19 cases) most commonly involved TG (12), TPO (four), DUOX2 (two), and TSHR (one). Ten cases harbored triallelic (digenic) mutations: TG and TPO (one); SLC26A4 and TPO (three), and DUOX2 and TG (six cases). Novel variants overall included 15 TG, six TPO, and three DUOX2 mutations. Genetic basis was not ascertained in 20 patients, including 14 familial cases. Conclusions: The etiology of CH with GIS remains elusive, with only 59% attributable to mutations in TSHR or known dyshormonogenesis-associated genes in a cohort enriched for familial cases. Biallelic TG or TPO mutations most commonly underlie severe CH. Triallelic defects are frequent, mandating future segregation studies in larger kindreds to assess their contribution to variable phenotype. A high proportion (-41%) of unsolved or ambiguous cases suggests novel genetic etiologies that remain to be elucidated.
Locus heterogeneity and novel TSHR mutations in consanguineous families with congenital non-goitrous hypothyroidism
(BMJ Publing Group, 2010-09) Cangül, Hakan; Aycan, Zehra; Morgan, Neil; Forman, Julia; Çetinkaya, Semra; Baş, Veysel; Demir, Korcan; Yuca, Sevil Arı; Kirby, Gail; Pasha, Shanaz; Kendall, Michaela; Hoegler, Wolfgang; Barret, T. G.; Maher, E. R.; Sağlam, Halil; Yakut, Tahsin; Gülten, Tuna; Karkucak, Mutlu; Eren, Erdal; Uludağ Üniversitesi/Tıp Fakültesi/Çocuk Sağlığı ve Hastalıkları Anabilim Dalı.; Uludağ Üniversitesi/Tıp Fakültesi/Tıbbi Genetik Anabilim Dalı.; 0000-0003-0710-5422; 0000-0002-1684-1053; C-7392-2019; AAM-1734-2020
Novel TSHR mutations in consanguineous families with congenital nongoitrous hypothyroidism
(Wiley, 2010-11) Morgan, Neil V.; Forman, Julia R.; Aycan, Zehra; Böber, Ece; Cesur, Yaşar; Kirby, Gail A.; Pasha, Shanaz S.; Çetinkaya, Semra Çağlar; Baş, Veysel Nihat; Demir, Korcan; Yuca, Sevil Arı; Meyer, Esther; Högler, Wolfgang; Timothy Barrett, Timothy; Mäher, Eamonn Richard; Cangül, Hakan; Sağlam, Halil; Yakut, Tahsin; Gülten, Tuna; Tarım, Ömer Faruk; Karkucak, Mutlu; Eren, Erdal; Kendall, Michaela; Uludağ Üniversitesi/Tıp Fakültesi/Tıbbi Genetik Anabilim Dalı.; Uludağ Üniversitesi/Tıp Fakültesi/Çocuk Sağlığı ve Hastalıkları Anabilim Dalı.; Uludağ Üniversitesi/Tıp Fakültesi/Halk Sağlığı Anabilim Dalı.; 0000-0003-0710-5422; 0000-0002-1684-1053; C-7392-2019; AAM-1734-2020; 8911611600; 35612700100; 6602802424; 6505944216; 6701427186; 35388323500; 36113153400; 8062516400
Objective Nonsyndromic autosomal recessively inherited non-goitrous congenital hypothyroidism (CHNG) can be caused by mutations in TSHR, PAX8, TSHB and NKX2-5. We aimed to investigate mutational frequencies of these genes and genotype/phenotype correlations in consanguineous families with CHNG. Design Because consanguinity in individuals with a presumptive genetic condition is often an indicator of an autosomal recessive inheritance and allows firmer correlations to be established between genotype and phenotype, we planned to execute our study in consanguineous families. Patients Hundred and thirty-nine children with CHNG phenotype born to consanguineous families. Measurements First, we investigated cases for evidence of linkage to the four known CHNG genes by microsatellite marker analysis. Mutation analysis by direct sequencing was then performed in those cases in whom linkage to the relevant candidate gene could not be excluded. In addition, in silico analysis of the predicted structural effects of TSHR mutations was performed and related to the mutation-specific disease phenotype. Results Homozygous germline TSHR mutations were detected in six families (5%), but no mutations were detected in PAX8, TSHB and NKX2-5. Four of TSHR mutations had not previously been described. Genotype-phenotype correlations were established and found to be related to the predicted structural effects of the mutations. Conclusions Known causative genes account for the development of CHNG only in a minority of cases, and our cohort should provide a powerful resource to identify novel causative genes and to delineate the extent of locus heterogeneity in autosomal recessively inherited CHNG.
Rare causes of primary adrenal insufficiency: Genetic and clinical characterization of a large nationwide cohort
(Endocrine Soc, 2016-01) Güran, Tülay; Buonocore, Federica; Saka, Nurçin; Özbek, Mehmet Nuri; Aycan, Zehra; Bereket, Abdullah; Baş, Firdevs; Darcan, Sükran; Bideci, Aysun; Güven, Ayla; Demir, Korcan; Akıncı, Ayşehan; Büyükinan, Muammer; Aydın, Banu Küçükemre; Turan, Serap; Ağladıoğlu, Sebahat Yılmaz; Atay, Zeynep; Abalı, Zehra Yavaş; Çatlı, Gönül; Yüksel, Bilgin; Akçay, Teoman; Yıldız, Metin; Özen, Samim; Doger, Esra; Demirbilek, Hüseyin; Uçar, Ahmet; Işık, Emregül; Özhan, Bayaram; Bolu, Semih; Özgen, İlker Tolga; Suntharalingham, Jenifer P.; Achermann, John C.; Tarım, Ömer; Uludağ Üniversitesi/Tıp Fakültesi/Pediatrik Endokrinoloji ve Diyabet Anabilim Dalı.; 6701427186
Context: Primary adrenal insufficiency (PAI) is a life-threatening condition that is often due to monogenic causes in children. Although congenital adrenal hyperplasia occurs commonly, several other important molecular causes have been reported, often with overlapping clinical and biochemical features. The relative prevalence of these conditions is not known, but making a specific diagnosis can have important implications for management. Objective: The objective of the study was to investigate the clinical and molecular genetic characteristics of a nationwide cohort of children with PAI of unknown etiology. Design: A structured questionnaire was used to evaluate clinical, biochemical, and imaging data. Genetic analysis was performed using Haloplex capture and next-generation sequencing. Patients with congenital adrenal hyperplasia, adrenoleukodystrophy, autoimmune adrenal insufficiency, or obvious syndromic PAI were excluded. Setting: The study was conducted in 19 tertiary pediatric endocrinology clinics. Patients: Ninety-five children (48 females, aged 0-18 y, eight familial) with PAI of unknown etiology participated in the study. Results: A genetic diagnosis was obtained in 77 patients (81%). The range of etiologies was as follows: MC2R (n = 25), NR0B1 (n = 12), STAR (n = 11), CYP11A1 (n = 9), MRAP (n = 9), NNT (n = 7), ABCD1 (n = 2), NR5A1 (n = 1), and AAAS (n = 1). Recurrent mutations occurred in several genes, such as c.560delT in MC2R, p.R451W in CYP11A1, and c. IVS3ds + 1delG in MRAP. Several important clinical and molecular insights emerged. Conclusion: This is the largest nationwide study of the molecular genetics of childhood PAI undertaken. Achieving a molecular diagnosis in more than 80% of children has important translational impact for counseling families, presymptomatic diagnosis, personalized treatment (eg, mineralocorticoid replacement), predicting comorbidities (eg, neurological, puberty/fertility), and targeting clinical genetic testing in the future.
Thyroid dyshormonogenesis is mainly caused by TPO mutations in consanguineous community
(Wiley, 2013-08) Cangül, Hakan; Aycan, Zehra; Nappa, Alvaro Olivera; Schoenmakers, Nadia A.; Boelaert, Kristien; Çetinkaya, Semra Çaǧlar; Böber, Ece; Darendeliler, Feyza F.; Baş, Veysel Nijat; Demir, Korcan; Saǧlam, Halil; Tarım, Ömer Faruk; Uludağ Üniversitesi/Tıp Fakültesi/Pediatrik Endokrinoloji Anabilim Dalı.; 0000-0003-0710-5422; C-7392-2019; 35612700100; 6701427186
Objective In this study, we aimed to investigate the genetic background of thyroid dyshormonogenesis (TDH). Context Thyroid dyshormonogenesis comprises 10-15% of all cases of congenital hypothyroidism (CH), which is the most common neonatal endocrine disorder, and might result from disruptions at any stage of thyroid hormone biosynthesis. Currently seven genes (NIS, TPO, PDS, TG, IYD, DUOX2 and DUOXA2) have been implicated in the aetiology of the disease. Design As TDH is mostly inherited in an autosomal recessive manner, we planned to conduct the study in consanguineous/multi-case families. Patients One hundred and four patients with congenital TDH all coming from consanguineous and/or multi-case families. Measurements Initially, we performed potential linkage analysis of cases to all seven causative-TDH loci as well as direct sequencing of the TPO gene in cases we could not exclude linkage to this locus. In addition, in silico analyses of novel missense mutations were carried out. Results TPO had the highest potential for linkage and we identified 21 TPO mutations in 28 TDH cases showing potential linkage to this locus. Four of 10 distinct TPO mutations detected in this study were novel (A5T, Y55X, E596X, D633N). Conclusions This study underlines the importance of molecular genetic studies in diagnosis, classification and prognosis of CH and proposes a comprehensive mutation screening by new sequencing technology in all newly diagnosed primary CH cases.