Person: BEREKET, ABDULLAH
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BEREKET
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ABDULLAH
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Publication Metadata only Effects of leukemia inhibitory receptor gene mutations on human hypothalamo-pituitary-adrenal function(SPRINGER, 2015) BEREKET, ABDULLAH; Guran, Tulay; Guran, Omer; Paketci, Cem; Kipoglu, Osman; Firat, Irfan; Turan, Serap; Atay, Zeynep; Haliloglu, Belma; Bereket, AbdullahStuve-Wiedemann syndrome (STWS) (MIM #601559) is a rare autosomal recessive disorder caused by mutations in the leukemia inhibitory factor receptor (LIFR) gene. STWS has a diverse range of clinical features involving hematopoietic, skeletal, neuronal and immune systems. STWS manifests a high mortality due to increased risk of sudden death. Heterodimerization of the LIFR mediates leukemia inhibitory factor (LIF) signalling through the intracellular Janus kinase (JAK)/STAT3 signalling cascade. The LIF/LIFR system is highly expressed in and regulates the hypothalamo-pituitary-adrenal (HPA) axis. HPA function was investigated in three STWS patients to characterise consequences of impaired LIF/LIFR signalling on adrenal function. Six genetically proven STWS patients from four unrelated Turkish families were included in the study. Sudden death occurred in three before 2 years of age. Basal adrenal function tests were performed by measurement of early morning serum cortisol and plasma ACTH concentrations on at least two different occasions. Low dose synacthen stimulation test and glucagon stimulation tests were performed to explore adrenal function in three patients who survived. All patients carried the same LIFR (p.Arg692X) mutation. Our oldest patient had attenuated morning serum cortisol and plasma ACTH levels at repeated measurements. Two of three patients had attenuated cortisol response (< 18 mu g/dl) to glucagon, one of whom also had borderline cortisol response to low dose (1 mu g) ACTH stimulation consistent with central adrenal insufficiency. STWS patients may develop central adrenal insufficiency due to impaired LIF/LIFR signalling. LIF/LIFR system plays a role in human HPA axis regulation.Publication Open Access GCK gene mutations are a common cause of childhood-onset MODY (maturity-onset diabetes of the young) in Turkey(WILEY-BLACKWELL, 2016-09) BEREKET, ABDULLAH; Haliloglu, Belma; Hysenaj, Gerald; Atay, Zeynep; Guran, Tulay; Abali, Saygin; Turan, Serap; Bereket, Abdullah; Ellard, SianObjectiveInactivating heterozygous mutations in the GCK gene are a common cause of MODY and result in mild fasting hyperglycaemia, which does not require treatment. We aimed to identify the frequency, clinical and molecular features of GCK mutations in a Turkish paediatric cohort. Design and PatientsFifty-four unrelated probands were selected based on the following criteria: age of diagnosis 17years, family history of diabetes in at least two generations, anti-GAD/ICA negative, BMI<95.p and follow-up with diet, oral antidiabetic drug or low-dose insulin treatment (05U/kg/d). A MODY probability score () was calculated and 21 patients with a score 75%, HbA1c levels 75% (585mmol/mol) and fasting blood glucose (FBG) levels 99-145mg/dl (55-80mmol/l) were selected for Sanger sequencing of the GCK gene. Targeted next-generation sequencing for all known monogenic diabetes genes was undertaken for any patient without a GCK gene mutation. ResultsGCK gene mutations (pathogenic or likely pathogenic variants) and a novel intronic variant of uncertain significance (c.208+3A>T) were identified in 13/54 probands (24%). Twelve of these patients had a MODY probability score 75%. FBG level and 2-h glucose level in OGTT were 12314mg/dl (68 +/- 07mmol/l) (107-157mg/dl) and 181 +/- 30mg/dl (101 +/- 16mmol/l) (136-247mg/dl), respectively. Average of glucose increment in OGTT was 58 +/- 27mg/dl (32 +/- 15mmol/l) (19-120mg/dl), and mean HbA1c level was 65 +/- 05% (475 +/- 55mmol/mol) (59-76%). Five novel missense mutations were identified (p.F123S, p.L58P, p.G246A, p.F419C, and p.S151C). Two patients treated with low-dose insulin before the molecular analysis were able to stop treatment. ConclusionsApproximately 1 in 4 MODY cases in this Turkish paediatric cohort have a GCK mutation. Selection of patients for GCK gene analysis using the MODY probability score was an effective way of identifying most (11/12) patients with a GCK mutation.Publication Metadata only Evaluation and Treatment Results of Ovarian Cysts in Childhood and Adolescence: A Multicenter, Retrospective Study of 100 Patients(ELSEVIER SCIENCE INC, 2017) BEREKET, ABDULLAH; Aydin, Banu Kucukemre; Saka, Nurcin; Bas, Firdevs; Yilmaz, Yasin; Haliloglu, Belma; Guran, Tulay; Turan, Serap; Bereket, Abdullah; Mutlu, Gul Yesiltepe; Cizmecioglu, Filiz; Hatun, Sukru; Bezen, Digdem; Tutunculer, Filiz; Cebeci, Nurcan; Isguven, Pinar; Memioglu, Nihal; Ercan, Oya; Poyrazoglu, Sukran; Bundak, Ruveyde; Darendeliler, FeyzaStudy Objective: To investigate the characteristics of children with ovarian cysts and evaluate treatment strategies. Design: Retrospective study. Setting: Eight pediatric endocrinology clinics, Turkey. Participants: A total of 100 children and adolescents with ovarian cysts. Interventions: Patient data collected via retrospective chart review. Patients were stratified according to age into 4 groups (newborns, 1-12 months, 1-8 years, and 8-18 years). Main Outcome Measures: Special emphasis was given to torsion and tumor cases, concomitant diseases, treatment modalities, and problems during follow-up. Results: Most newborns and infants were asymptomatic with the cysts being discovered incidentally; in girls ages 1-8, symptoms were common, including breast budding (47.1%, 16 of 34) and vaginal bleeding (29.4%, 10 of 34). Girls older than 8 years mostly presented with abdominal pain (31.6%, 12 of 38) and menstrual irregularity (21.1%, 8 of 38). Most of our patients were diagnosed with a simple ovarian cyst, but 9 patients were found to have ovarian tumors. Ovarian torsion was detected in 7 patients; 5 with large and 2 with small cysts (! 20 mm). Two patients had central precocious puberty (CPP) at presentation and 5 patients developed CPP during follow-up. The surgical intervention rate was high (38%, 38 of 100), but was associated with earlier treatment year, and this association remained significant after adjusting for confounders (P = .035). Conclusion: Most girls have simple cysts, which have a favorable prognosis without intervention; however, there might be coexisting pathologies or complications such as tumors, torsion, and CPP; hence these patients should be evaluated accordingly and treated with a multidisciplinary approach.