Person: BEREKET, ABDULLAH
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BEREKET
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ABDULLAH
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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 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.Publication Open Access Biallelic and monoallelic ESR2 variants associated with 46,XY disorders of sex development(2018-07) BEREKET, ABDULLAH; Baetens, Dorien; Güran, Tülay; Mendonca, Berenice B.; Gomes, Nathalia L.; De Cauwer, Lode; Peelman, Frank; Verdin, Hannah; Vuylsteke, Marnik; Van der Linden, Malaïka; Stoop, Hans; Looijenga, Leendert H.; De Bosscher, Karolien; Cools, Martine; De Baere, Elfride; Atay, Zeynep; Bereket, Abdullah; de Krijger, Ronald R.; Preter, Katleen de; Domenice, Sorahia; Turan, SerapPublication Open Access A novel deletion involving the first GNAS exon encoding Gsα causes PHP1A without methylation changes at exon A/B(2022-04-01) BEREKET, ABDULLAH; DEMİRCİOĞLU, SERAP; GÜRAN, TÜLAY; Campbell D., Reyes M., Kaygusuz S. B., Abalı S., Güran T., Bereket A., Kagami M., Turan S., Jüppner H.© 2022Individuals affected by pseudohypoparathyroidism type 1A (PHP1A) display hyperphosphatemia and hypocalcemia despite elevated PTH levels, as well as features of Albright Hereditary Osteodystrophy (AHO). PHP1A is caused by variants involving the maternal GNAS exons 1–13 encoding the stimulatory G protein α-subunit (Gsα). MLPA and aCGH analysis led in a male PHP1A patient to identification of a de novo 1284-bp deletion involving GNAS exon 1. This novel variant overlaps with a previously identified 1438-bp deletion in another PHP1A patient (ref. Li et al. (2020) [13], patient 2) that extends from the exon 1 promoter into the up-stream intronic region. This latter deletion is associated with reduced methylation at GNAS exon A/B, i.e. the differentially methylated region (DMR) that is demethylated in most pseudohypoparathyroidism type 1B (PHP1B) patients. In contrast, genomic DNA from our patient revealed no evidence for an epigenetic GNAS defect as determined by MS-MLPA and pyrosequencing. These findings thus reduce the region, which, in addition to other nucleotide sequences telomeric of exon A/B, may undergo histone modifications or interacts with transcription factors and possibly as-yet unknown proteins that are required for establishing the maternal methylation imprints at this site. Taken together, nucleotide deletions or changes within an approximately 1300-bp region telomeric of exon A/B could be a cause of PHP1B variants with complete or incomplete loss-of-methylation at the exon A/B DMR. In addition, when investigating patients with suspected PHP1A, MLPA should be considered to search for structural abnormalities within this difficult to analyze genomic region comprising GNAS exon 1.Publication Open Access Maternal Thyroid Dysfunction and Neonatal Thyroid Problems(HINDAWI LTD, 2013) BEREKET, ABDULLAH; Ozdemir, Hulya; Akman, Ipek; Coskun, Senay; Demirel, Utku; Turan, Serap; Bereket, Abdullah; Bilgen, Hulya; Ozek, ErenAim. To investigate obstetric features of pregnant women with thyroid disorders and thyroid function tests of their newborn infants. Methods. Women with hypothyroidism and having anti-thyroglobulin (ATG) and anti-thyroid peroxidase (anti-TPO) antibodies were assigned as group I, women with hypothyroidism who did not have autoantibodies were assigned as group II, and women without thyroid problems were assigned as group III. Results. Pregnant women with autoimmune hypothyroidism (group I) had more preterm delivery and their babies needed more frequent neonatal intensive care unit (NICU) admission. In group I, one infant was diagnosed with compensated hypothyroidism and one infant had transient hyperthyrotropinemia. Five infants (23.8%) in group II had thyroid-stimulating hormone (TSH) levels >20 mIU/mL. Only two of them had TSH level >7 mIU/L at the 3rd postnatal week, and all had normal free T4 (FT4). Median maternal TSH level of these five infants with TSH >20 mIU/mL was 6.6 mIU/mL. In group III, six infants (6.5%) had TSH levels above >20 mIU/mL at the 1st postnatal week. Conclusion. Infants of mothers with thyroid problems are more likely to have elevated TSH and higher recall rate on neonatal thyroid screening. Women with thyroid disorders and their newborn infants should be followed closely for both obstetrical problems and for thyroid dysfunction.Publication Open Access Homozygous Loss-of-function Mutations in SOHLH1 in Patients With Nonsyndromic Hypergonadotropic Hypogonadism(OXFORD UNIV PRESS INC, 2015-05) BEREKET, ABDULLAH; Bayram, Yavuz; Gulsuner, Suleyman; Guran, Tulay; Abaci, Ayhan; Yesil, Gozde; Gulsuner, Hilal Unal; Atay, Zeynep; Pierce, Sarah B.; Gambin, Tomasz; Lee, Ming; Turan, Serap; Bober, Ece; Atik, Mehmed M.; Walsh, Tom; Karaca, Ender; Pehlivan, Davut; Jhangiani, Shalini N.; Muzny, Donna; Bereket, Abdullah; Buyukgebiz, Atilla; Boerwinkle, Eric; Gibbs, Richard A.; King, Mary-Claire; Lupski, James R.Context: Hypergonadotropic hypogonadism presents in females with delayed or arrested puberty, primary or secondary amenorrhea due to gonadal dysfunction, and is further characterized by elevated gonadotropins and low sex steroids. Chromosomal aberrations and various specific gene defects can lead to hypergonadotropic hypogonadism. Responsible genes include those with roles in gonadal development or maintenance, sex steroid synthesis, or end-organ resistance to gonadotropins. Identification of novel causative genes in this disorder will contribute to our understanding of the regulation of human reproductive function. Objectives: The aim of this study was to identify and report the gene responsible for autosomal-recessive hypergonadotropic hypogonadism in two unrelated families. Design and Participants: Clinical evaluation and whole-exome sequencing were performed in two pairs of sisters with nonsyndromic hypergonadotropic hypogonadism from two unrelated families. Results: Exome sequencing analysis revealed two different truncating mutations in the same gene: SOHLH1 c.705delT (p.Pro235fs*4) and SOHLH1 c.27C>G (p.Tyr9stop). Both mutations were unique to the families and segregation was consistent with Mendelian expectations for an autosomal-recessive mode of inheritance. Conclusions: Sohlh1 was known from previous mouse studies to be a transcriptional regulator that functions in the maintenance and survival of primordial ovarian follicles, but loss-of-function mutations in human females have not been reported. Our results provide evidence that homozygous-truncating mutations in SOHLH1 cause female nonsyndromic hypergonadotropic hypogonadism.Publication Open Access Constitutional Growth Delay Pattern of Growth in Velo-Cardio-Facial Syndrome: Longitudinal follow up and final height of two cases(2008) BEREKET, ABDULLAH; Turan, Serap; Ozdemir, Nihal; Güran, Tülay; Akalın, Figen; Akçay, Teoman; Ayabakan, Canan; Yılmaz, Yüksel; Bereket, AbdullahWe report two patients with velo-cardio-facial syndrome (VCFS) who were admitted to our pediatric endocrinology clinic because of short stature and followed longitudinally until attainment of final height. Both patients followed a growth pattern consistent with constitutional delay of puberty with normal and near normal final height. Case 2 also had partial growth hormone (GH) deficiency and severe short stature (height SDS -3.4 SDS), but showed spontaneous catch-up and ended up with a final height of -2 SDS. These cases suggest that short stature in children with VCFS is due to a pattern of growth similar to that observed in constitutional delay of growth and puberty.