Browsing by Author "Guran, Tulay"

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A novel deletion involving the first GNAS exon encoding Gs alpha causes PHP1A without methylation changes at exon A/B
(ELSEVIER SCIENCE INC, 2022-01-01) Campbell, Devon; Reyes, Monica; Kaygusuz, Sare Betul; Abali, Saygin; Guran, Tulay; Bereket, Abdullah; Kagami, Masayo; Turan, Serap; Juppner, Harald
Individuals 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 alpha-subunit (Gs alpha). 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.
Cathepsin K analysis in a pycnodysostosis cohort: demographic, genotypic and phenotypic features
(BIOMED CENTRAL LTD, 2014-01-01) Arman, Ahmet; Bereket, Abdullah; Coker, Ajda; Kiper, Pelin Ozlem Simsek; Guran, Tulay; Ozkan, Behzat; Atay, Zeynep; Akcay, Teoman; Haliloglu, Belma; Boduroglu, Koray; Alanay, Yasemin; Turan, Serap
Background: To characterize cathepsin K (CTSK) mutations in a group of patients with pycnodysostosis, who presented with either short stature or atypical fractures to pediatric endocrinology or dysmorphic features to pediatric genetics clinics. Methods: Seven exons and exon/intron boundaries of CTSK gene for the children and their families were amplified with PCR and sequenced. Sixteen patients from 14 families with pycnodysostosis, presenting with typical dysmorphic features, short stature, frequent fractures and osteosclerosis, were included in the study. Results: We identified five missense mutations (M1I, I249T, L7P, D80Y and D169N), one nonsense mutation (R312X) and one 301 bp insertion in intron 7, which is revealed as Alu sequence
Cranial MRI Abnormalities and Long-term Follow-up of the Lesions in 770 Girls With Central Precocious Puberty
(ENDOCRINE SOC, 2021-01-01) Helvacioglu, Didem; Turan, Serap Demircioglu; Guran, Tulay; Atay, Zeynep; Dagcinar, Adnan; Bezen, Digdem; Ozturan, Esin Karakilic; Darendeliler, Feyza; Yuksel, Aysegul; Dursun, Fatma; Kilinc, Suna; Semiz, Serap; Abali, Saygin; Yildiz, Metin; Onder, Asan; Bereket, Abdullah
Context: Central precocious puberty (CPP) may arise from central nervous system (CNS) lesions in a few affected girls. Recently, the incidence of girls with CPP has increased mostly in 6-8 year olds, in whom the necessity of magnetic resonance imaging (MRI) is debated. Objective: To investigate the frequency, long-term outcome and potential predictors of CNS lesions in a large cohort of girls with CPP. Methods: A multicenter cohort of 770 Turkish girls with CPP who had systematic cranial MRI between 2005 and 2017. Age at puberty onset was <6 years in 116 and 6-8 years in 654. CNS lesions were followed until final decision(6.2 +/- 3.1 years). Potential predictors of CNS lesions were evaluated by univariate analyses. Results: A total of 104/770 (13.5\%) girls had abnormal brain MRI. Of these, 2.8\% were previously known CNS lesions, 3.8\% had newly detected and causally related CNS lesions, 3.1 \% were possibly, related and 3.8\% were incidental. Only 2 (0.25\%) neoplastic lesions (1 low grade glioma and 1 meningioma) were identified
Incidence of Type 1 Diabetes in Children Aged Below 18 Years during 2013-2015 in Northwest Turkey
(GALENOS YAYINCILIK, 2018-01-01) Poyrazoglu, Sukran; Bundak, Ruveyde; Abali, Zehra Yavas; Onal, Hasan; Sarikaya, Sevil; Akgun, Abdurrahman; Bas, Serpil; Abali, Saygin; Bereket, Abdullah; Eren, Erdal; Tarim, Omer; Guven, Ayla; Yildiz, Metin; Aksakal, Derya Karaman; Yuksel, Aysegul; Karabulut, Gulcan Seymen; Hatun, Sukru; Ozgen, Tolga; Cesur, Yasar; Azizoglu, Mehmet; Dilek, Emine; Tutunculer, Filiz; Cakir, Esra Papatya; Ozcabi, Bahar; Evliyaoglu, Olcay; Karadeniz, Songul; Dursun, Fatma; Bolu, Semih; Arslanoglu, Ilknur; Mutlu, Gul Yesiltepe; Kirmizibekmez, Heves; Isguven, Pinar; Ustyol, Ala; Adal, Erdal; Ucar, Ahmet; Cebeci, Nurcan; Bezen, Didem; Binay, Cigdem; Semiz, Serap; Korkmaz, Huseyin Anil; Memioglu, Nihal; Sagsak, Elif; Peltek, Havva Nur; Yildiz, Melek; Akcay, Teoman; Turan, Serap; Guran, Tulay; Atay, Zeynep; Akcan, Nese; Cizmecioglu, Filiz; Ercan, Oya; Dagdeviren, Aydilek; Bas, Firdevs; Issever, Halim; Darendeliler, Feyza
Objective: To assess the incidence of type I diabetes mellitus (T1DM) in children under 18 years of age in the northwest region of Turkey during 2013-2015. Methods: All newly diagnosed T1DM cases were recorded prospectively during 2013-2015. Total, as well as gender and age group specific (0-4, 5-9. 10-14 and 15-17 age) mean incidences per 100,000 per year were calculated. Results: There were 1,773 patients diagnosed during 2013-2015 (588 cases in 2013, 592 cases in 2014, 593 cases in 2015). Of these, 862 (48.6 \%) were girls and 911 (51.4\%)were boys. The mean age at diagnosis was 9.2 +/- 4.2 years and it was not significantly different between girls (9.0 +/- 4.1 years) and boys (9.4 +/- 4.4 years) (p = 0.052). The crude mean incidence was 8.99/100.000 confidence interval (CI) (95\% CI: 8.58-9.42). Although mean incidence was similar between boys {[}8.98/100.000 (CI: 8.40 to 9.58)] and girls {[}9.01/100.000 (CI: 8.42 to 9.63)], there was male predominance in all groups except for 5-9 year age group. The standardized mean incidence was 9.02/100.000 according to the World Health Organization standard population. The mean incidence for the 0-4, 5-9, 10-14 and 15-17 age groups was 6.13, 11.68, 11.7 and 5.04/1 00.000 respectively. The incidence of T1DM was similar over the course of three years (p = 0.95). A significant increase in the proportion of cases diagnosed was observed in the autumn-winter seasons. Conclusion: The northwest region of Turkey experienced an intermediate incidence of T1DM over the period of the study.
The Distribution of Different Types of Diabetes in Childhood: A Single Center Experience
(GALENOS YAYINCILIK, 2018-01-01) Haliloglu, Belma; Abali, Saygin; Bugrul, Fuat; Celik, Enes; Bas, Serpil; Atay, Zeynep; Guran, Tulay; Turan, Serap; Bereket, Abdullah
Objective: Type I diabetes (T1D) is the most common cause of diabetes in childhood but type 2 diabetes (T2D) and maturity onset diabetes of the young (MODY) are emerging as noteworthy causes of diabetes at young ages. The aim is to determine the distribution, trends and clinical features of the different types of diabetes in childhood in one tertiary center. Methods: The records of children and adolescents aged 0-18 years who were diagnosed as ``diabetes/persistent hyperglycemia{''} between January 1999 and December 2016, were reviewed. Clinical and laboratory characteristics of the patients at diagnosis and type of diabetes were recorded. Results: The mean +/- standard deviation age of 835 patients (48.7\% females) at diagnosis was 8.8 +/- 4.4 years. Eighty-four percent of the patients were diagnosed as T1D, 5.7\% as T2D, 5.3\% as clinical MODY and 5\% as being cases of other types of diabetes. The frequency of diabetic ketoacidosis (DKA) and severe DKA in T1D were 48.4\% and 11.6\%, respectively. Fourteen patients (29.2 \%) with T2D presented with ketosis and two of them (4.2 \%) had DKA at diagnosis. Antibody positivity was 83.1 \% in T1D and 14.8\% in T2D. A statistically significant increase in the frequency of T2D has clearly been demonstrated in recent years with a frequency of 1.9\%, 2.4\% and 7.9\% in 1999-2004, 2005-2010 and 2011-2016, respectively (p <0.001). In MODY, genetic analysis was performed in 26 (59\%) patients and NNF1A and GCK gene mutations were detected in 3 (11.5\%) and 14 (53.8\%) patients, respectively. Conclusion: Although the most frequent cause of DM is T1D in childhood, a trend towards increase in the frequency of T2D in recent years is notable in our population.