Person: BEREKET, ABDULLAH
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BEREKET
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ABDULLAH
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Publication Metadata only Oral bisphosphonate therapy for vitamin D intoxication of the infant(AMER ACAD PEDIATRICS, 2003) BEREKET, ABDULLAH; Bereket, A; Erdogan, TVitamin D intoxication in infancy has serious consequences attributable to acute hypercalcemia and subsequent hypercalcuria/nephrocalcinosis. Current treatments of patients with vitamin D intoxication are unsatisfactory and associated with prolonged hypercalcemia. We now report the use of oral alendronate sodium in a 3-month-old infant with vitamin D intoxication. Short-term oral alendronate sodium treatment effectively corrected hypercalcemia/hypercalciuria, decreased the duration of hospitalization, and appears safe in 15 months of observation.Publication Metadata only Clinical Significance of Hypophosphatasemia in Children(SPRINGER, 2020) BEREKET, ABDULLAH; Bayramli, Rana; Cevlik, Tulay; Guran, Tulay; Atay, Zeynep; Bas, Serpil; Haklar, Goncagul; Bereket, Abdullah; Turan, SerapLow serum alkaline phosphatase (sALP)-hypophosphatasemia-is a characteristic of hypophosphatasia (HPP), but related to several clinical conditions. Here, we evaluated the frequency, persistency and the etiology of hypophosphatasemia in children. In retrospective analyses of sALP measurements from children, evaluated according to in-house constructed age- and sex-specific reference ranges, patients with no normal sALP measurement (Unresolved hypophosphatasemia) were invited for reanalysis. Prospectively, ALP substrates, pyridoxal-5-phosphate (PLP), and phosphoethanolamine (PEA) were measured in patients with persistent hypophosphatasemia. Radiographs and ALPL gene sequencing for HPP were performed to the cases with elevated PEA and/or PLP. From 130,340 sALP measurements of 93,162 patients, hypophosphatasemia was detected in 1404 samples from 867 patients (0.9%). Among them, 745 had at least one normal sALP values in laboratory records, grouped as transient hypophosphatasemia. 75 out of 122 patients with unresolved hypophosphatasemia could be reanalyzed for sALP, of whom PLP and PEA measurements were required in 37 due to persistent hypophosphatasemia. Both PEA and PLP were elevated in 4 patients, and ALPL gene analysis showed heterozygous mutations in 3 patients and homozygous in 1 patient. Elevated PEA with normal PLP were detected in 3 patients, and one had a heterozygous ALPL mutation. Anemia was the most common diagnosis, and upper respiratory tract infections and chronic diseases were more common in transient and unresolved hypophosphatasemia, respectively. In conclusion, reflected persistent hypophosphatasemia frequency was 1/1552 (0.06%) in this large pediatric cohort and, ALPL gene mutations were detected in 13.5% (5/37) of the studied cases. Although biochemical hypophosphatasemia is not uncommon, clinically significant HPP is rare.Publication Metadata only Evaluation of therapeutics management patterns and glycemic control of pediatric type 1 diabetes mellitus patients in Turkey: A nationwide cross-sectional study(ELSEVIER IRELAND LTD, 2016) BEREKET, ABDULLAH; Hatun, Sukru; Demirbilek, Huseyin; Darcan, Sukran; Yuksel, Aysegul; Binay, Cigdem; Simsek, Damla Goksen; Kara, Cengiz; Cetinkaya, Ergun; Unuvar, Tolga; Ucakturk, Ahmet; Tutunculer, Filiz; Cesur, Yasar; Bundak, Ruveyde; Saglam, Halil; Simsek, Enver; Bereket, AbdullahAims: To evaluate the management strategies, glycemic control and complications of pediatric type 1 diabetes mellitus (T1DM) patients in Turkey. Methods: Study included 498 patients with T1DM between the ages 1-18. Data provided from patients' hospital files were recorded on standard case report forms by applicant clinicians within the 3 months of data collection period between October 2012 and July 2013. Results: Mean age of patients was 11.3 +/- 3.8 years. Mean duration of DM was determined as 3.7 +/- 3.1 years. Majority of patients (85.5%) used basal/bolus injection (BBI), and 6.5% used continuous subcutaneous insulin infusion pump. Assessment of glycemic control based on HbA1c levels showed that 29.1% of patients had an HbA1c value <7.5% (58 mmol/mol), 16.1% had a value between 7.5% (58 mmol/mol) and 8% (64 mmol/mol), 19.1% had a value between 8.1% (64 mmol/mol) and 9%(75 mmol/mol) and 35.7% a value >9%(75 mmol/mol). Hypoglycemia was reported in 145 (29.1%) patients and the number of severe hypoglycemic attacks in the last 3 months was 1.0 +/- 2.4. Taking into consideration the carbohydrate count and insulin correction dose and parents with high socioeconomic status was related to have better glycemic control. The most common comorbidities were Hashimoto's thyroiditis/hypothyroidism (6.2%) followed by celiac disease (3.8%), epilepsy(1.2%), and asthma(1.0%). Conclusions: BBI insulin therapy is widely used among pediatric T1DM patients in Turkey. However, despite improvements in treatment facilities and diabetic care, glycemic control is not at a satisfactory level. Therefore, new and comprehensive initiatives require for pediatric T1DM patients with poor glycemic control. Promoting use of carbohydrate count and insulin correction doses may improve the glycemic control of pediatric T1DM in Turkey. (C) 2016 Elsevier Ireland Ltd. All rights reserved.Publication Metadata only The role of leptin, soluble leptin receptor, resistin, and insulin secretory dynamics in the pathogenesis of hypothalamic obesity in children(SPRINGER, 2009) BEREKET, ABDULLAH; Guran, Tulay; Turan, Serap; Bereket, Abdullah; Akcay, Teoman; Unluguzel, Goksenin; Bas, Firdevs; Gunoz, Hulya; Saka, Nurcin; Bundak, Ruveyde; Darendeliler, Feyza; Isguven, Pinar; Yildiz, Metin; Adal, Erdal; Sarikaya, Sevil; Baygin, Leyla Akin; Memioglu, Nihal; Onal, Hasan; Ercan, Oya; Haklar, GoncagulIn 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. 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. 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). 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.Publication Open Access Normative Data of Thyroid Volume-Ultrasonographic Evaluation of 422 Subjects Aged 0-55 Years(GALENOS YAYINCILIK, 2015-06-05) BEREKET, ABDULLAH; Aydiner, Omer; Aydiner, Elif Karakoc; Akpinar, Ihsan; Turan, Serap; Bereket, AbdullahObjective: To establish local normative data of thyroid volume assessed by ultrasonography in subjects aged 0-55 years living in Istanbul, Turkey. Methods: Subjects without any known history of thyroid disease, of major surgery and/or chronic disease were enrolled in the study and evaluated by physical examination and thyroid ultrasonography. Thyroid gland and isthmus at usual location, each lateral lobe volume with three dimensions, ectopic thyroid tissue and echogenicity of the gland were assessed. Results: Initially, 494 subjects were enrolled in the study. Subjects showing heterogeneous thyroid parenchyma (n=21) and/or nodule (n=51) in ultrasonography were excluded. Final analysis covered 422 subjects (216 males, 206 females). Thyroid volume was found to significantly correlate with height, weight, age and body surface area (r=0.661, r=0.712, r=0.772 and r=0.779, respectively; p<0.0001 for all). These correlations were even stronger in subjects younger than 18 years (r=0.758, r=0.800, r=0.815 and r=0.802, respectively; p<0.0001 for all). Conclusion: The study provides updated reference norms for thyroid volume in Turkish subjects which can be used in the diagnosis and follow-up of patients with thyroid diseases.Publication Open Access Growth curves for Turkish Girls with Turner Syndrome: Results of the Turkish Turner Syndrome Study Group(GALENOS YAYINCILIK, 2015-09-05) BEREKET, ABDULLAH; Darendeliler, Feyza; Yesilkaya, Ediz; Bereket, Abdullah; Bas, Firdevs; Bundak, Ruveyde; Sari, Erkan; Aydin, Banu Kucukemre; Darcan, Sukran; Dundar, Bumin; Buyukinan, Muammer; Kara, Cengiz; Mazicioglu, Mumtaz M.; Adal, Erdal; Akinci, Aysehan; Atabek, Mehmet Emre; Demirel, Fatma; Celik, Nurullah; Ozkan, Behzat; Ozhan, Bayram; Orbak, Zerrin; Ersoy, Betul; Dogan, Murat; Atas, Ali; Turan, Serap; Goksen, Damla; Tarim, Omer; Yuksel, Bilgin; Ercan, Oya; Hatun, Sukru; Simsek, Enver; Okten, Aysenur; Abaci, Ayhan; Doneray, Hakan; Ozbek, Mehmet Nuri; Keskin, Mehmet; Onal, Hasan; Akyurek, Nesibe; Bulan, Kezban; Tepe, Derya; Emeksiz, Hamdi Cihan; Demir, Korcan; Kizilay, Deniz; Topaloglu, Ali Kemal; Eren, Erdal; Ozen, Samim; Demirbilek, Huseyin; Abali, Saygin; Akin, Leyla; Eklioglu, Beray Selver; Kaba, Sultan; Anik, Ahmet; Bas, Serpil; Unuvar, Tolga; Saglam, Halil; Bolu, Semih; Ozgen, Tolga; Dogan, Durmus; Cakir, Esra Deniz; Sen, Yasar; Andiran, Nesibe; Cizmecioglu, Filiz; Evliyaoglu, Olcay; Karaguzel, Gulay; Pirgon, Ozgur; Catli, Gonul; Can, Hatice Dilek; Gurbuz, Fatih; Binay, Cigdem; Bas, Veysel Nijat; Saglam, Celal; Gul, Davut; Polat, Adem; Acikel, Cengizhan; Cinaz, PeyamiObjective: Children with Turner syndrome (TS) have a specific growth pattern that is quite different from that of healthy children. Many countries have population-specific growth charts for TS. Considering national and ethnic differences, we undertook this multicenter collaborative study to construct growth charts and reference values for height, weight and body mass index (BMI) from 3 years of age to adulthood for spontaneous growth of Turkish girls with TS. Methods: Cross-sectional height and weight data of 842 patients with TS, younger than 18 years of age and before starting any therapy, were evaluated. Results: The data were processed to calculate the 3rd, 10th, 25th, 50th, 75th, 90th and 97th percentile values for defined ages and to construct growth curves for height-for-age, weight-for-age and BMI-for-age of girls with TS. The growth pattern of TS girls in this series resembled the growth pattern of TS girls in other reports, but there were differences in height between our series and the others. Conclusion: This study provides disease-specific growth charts for Turkish girls with TS. These disease-specific national growth charts will serve to improve the evaluation of growth and its management with growth-promoting therapeutic agents in TS patients.Publication Open Access A Rare Cause of Hypophosphatemia: Raine Syndrome Changing Clinical Features with Age(SPRINGER, 2020-07) DAĞÇINAR, ADNAN; Eltan, Mehmet; Alavanda, Ceren; Yavas Abali, Zehra; Ergenekon, Pinar; Yalindag Ozturk, Nilufer; Sakar, Mustafa; Dagcinar, Adnan; Kirkgoz, Tarik; Kaygusuz, Sare Betul; Gokdemir, Yasemin; Elcioglu, Huriye Nursel; Guran, Tulay; Bereket, Abdullah; Ata, Pinar; Turan, SerapRaine 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.Publication Open Access Familial Hypomagnesemia with Hypercalciuria and Nephrocalcinosis Due to CLDN16 Gene Mutations: Novel Findings in Two Cases with Diverse Clinical Features(SPRINGER, 2021-11-11) BEREKET, ABDULLAH; Eltan, Mehmet; Abali, Zehra Yavas; Turkyilmaz, Ayberk; Gokce, Ibrahim; Abali, Saygin; Alavanda, Ceren; Arman, Ahmet; Kirkgoz, Tarik; Guran, Tulay; Hatun, Sukru; Bereket, Abdullah; Turan, SerapBiallelic loss of function mutations in the CLDN16 gene cause familial hypomagnesemia with hypercalciuria and nephrocalcinosis (FHHNC), and chronic kidney disease. Here we report two cases of FHHNC with diverse clinical presentations and hypercalcemia in one as a novel finding. Pt#1 initially presented with urinary tract infection and failure to thrive at 5.5 months of age to another center. Bilateral nephrocalcinosis, hypercalcemia (Ca: 12.2 mg/dl), elevated parathyroid hormone (PTH) level, and hypercalciuria were detected. Persistently elevated PTH with high/normal Ca levels led to subtotal-parathyroidectomy at the age of 2.5. However, PTH levels remained elevated with progressive deterioration in renal function. At 9-year-old, she was referred to us for evaluation of hyperparathyroidism and, hypomagnesemia together with hypercalciuria, elevated PTH with normal Ca levels, and medullary nephrocalcinosis were detected. Compound heterozygosity of CLDN16 variants (c.715G>A, p.G239R; and novel c.360C>A, p.C120*) confirmed the diagnosis. Pt#2 was a 10-month-old boy, admitted with irritability and urinary crystals. Hypocalcemia, hypophosphatemia, elevated PTH and ALP, low 25(OH)D levels, and radiographic findings of rickets were detected. However, additional findings of hypercalciuria and bilateral nephrocalcinosis were inconsistent with the nutritional rickets. Low/normal serum Mg levels suggested the diagnosis of FHHNC which was confirmed genetically as a homozygous missense (c.602G > A; p.G201E) variant in CLDN16. Yet, hypocalcemia and hypomagnesemia persisted in spite of treatment. In conclusion, FHHNC may present with diverse clinical features with mild hypomagnesemia leading to secondary hyperparathyroidism with changing Ca levels from low to high. Early and accurate clinical and molecular genetic diagnosis is important for proper management.Publication Metadata only Revisiting Classical 3 beta-hydroxysteroid Dehydrogenase 2 Deficiency: Lessons from 31 Pediatric Cases(ENDOCRINE SOC, 2020) BEREKET, ABDULLAH; Guran, Tulay; Kara, Cengiz; Yildiz, Melek; Bitkin, Eda C.; Haklar, Goncagul; Lin, Jen-Chieh; Keskin, Mehmet; Barnard, Lise; Anik, Ahmet; Catli, Gonul; Guven, Ayla; Kirel, Birgul; Tutunculer, Filiz; Onal, Hasan; Turan, Serap; Akcay, Teoman; Atay, Zeynep; Yilmaz, Gulay C.; Mamadova, Jamala; Akbarzade, Azad; Sirikci, Onder; Storbeck, Karl-Heinz; Baris, Tugba; Chung, Bon-Chu; Bereket, AbdullahContext: The clinical effects of classical 3 beta-hydroxysteroid dehydrogenase 2 (3 beta HSD2) deficiency are insufficiently defined due to a limited number of published cases. Objective: To evaluate an integrated steroid metabolome and the short- and long-term clinical features of 3 beta HSD2 deficiency. Design: Multicenter, cross-sectional study. Setting: Nine tertiary pediatric endocrinology clinics across Turkey. Patients: Children with clinical diagnosis of 3 beta HSD2 deficiency. Main Outcome Measures: Clinical manifestations, genotype-phenotype-metabolomic relations. A structured questionnaire was used to evaluate the data of patients with clinical 3 beta HSD2 deficiency. Genetic analysis of HSD3B2 was performed using Sanger sequencing. Novel HSD3B2 mutations were studied in vitro. Nineteen plasma adrenal steroids were measured using LC-MS/MS. Results: Eleven homozygous HSD3B2 mutations (6 novel) were identified in 31 children (19 male/12 female; mean age: 6.6 +/- 5.1 yrs). The patients with homozygous pathogenic HSD3B2 missense variants of > 5% of wild type 3 beta HSD2 activity in vitro had a non-salt-losing clinical phenotype. Ambiguous genitalia was an invariable feature of all genetic males, whereas only 1 of 12 female patients presented with virilized genitalia. Premature pubarche was observed in 78% of patients. In adolescence, menstrual irregularities and polycystic ovaries in females and adrenal rest tumors and gonadal failure in males were observed. Conclusions: Genetically-documented 3 beta HSD2 deficiency includes salt-losing and non-salt-losing clinical phenotypes. Spared mineralocorticoid function and unvirilized genitalia in females may lead to misdiagnosis and underestimation of the frequency of 3 beta HSD2 deficiency. High baseline 17OHPreg to cortisol ratio and low 11-oxyandrogen concentrations by LC-MS/MS unequivocally identifies patients with 3 beta HSD2 deficiency.Publication Open Access Homozygosity for a novel INHA mutation in two male siblings with hypospadias, primary hypogonadism, and high-normal testicular volume(2022-03-23) ŞAHİN, BAHADIR; DEMİRCİOĞLU, SERAP; BEREKET, ABDULLAH; GÜRAN, TÜLAY; Arslan Ateş E., Eltan M., Sahin B., Gurpinar Tosun B., Seven Menevse T., Geckinli B. B., Greenfield A., Turan S., Bereket A., Güran T.Background: The human INHA gene encodes the inhibin subunit alpha protein, which is common to both inhibin A and B. The functional importance of inhibins in male sex development, sexual function, and reproduction remain largely unknown. Objective: We report for the first time two male siblings with homozygous INHA mutations. Methods: The medical files were examined for clinical, biochemical, and imaging data. Genetic analysis was performed using next-generation and Sanger sequencing methods. Results: Two brothers complained of gynecomastia, testicular pain, and had a history of hypospadias. Biochemistry revealed low serum testosterone, high gonadotropin and anti-Mullerian hormone, and very low/undetectable inhibin concentrations, where available. Both patients had azoospermia in the spermiogram. We have identified a homozygous 2 bp deletion (c.208_209delAG, R70Gfs*3) variant, which leads to a truncated INHA protein in both patients, and confirmed heterozygosity in the parents. The external genital development, pubertal onset and progression, reproductive functions, serum gonadotropins, and sex hormones of mother and father, who were heterozygous carriers of the identified mutation, were normal. Conclusion: Homozygosity for INHA mutations causes decreased prenatal and postnatal testosterone production and infertility in males, while the heterozygous female and male carriers of INHA mutations do not have any abnormality in sex development and reproduction.