İlker Tolga Özgen

Prof. Dr. İlker Tolga Özgen


Research Focus & Metrics

Academic Career Length

20Years (2007-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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19 October 2010 in Biological Trace Element Research
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MTMehmet Emre Tascilar
Mehmet Emre Tascilar
İÖİlker Tolga Özgen
İlker Tolga Özgen
AAAyhan Abaci
Ayhan Abaci
MSMuhittin Serdar
Muhittin Serdar
OAOsman Aykut
Osman Aykut

7 May 2014 in Pediatric Nephrology
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Journal Article
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NGNilufer Goknar
Nilufer Goknar
FOFaruk Oktem
Faruk Oktem
İÖİlker Tolga Özgen
İlker Tolga Özgen
ETEmel Torun
Emel Torun
MKMehmet Kuçukkoc
Mehmet Kuçukkoc
YCYasar Cesur
Yasar Cesur

5 March 2015 in Journal of Clinical Research in Pediatric Endocrinology
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Journal Article
Open access
EYEdiz Yeşilkaya
Ediz Yeşilkaya
ABAbdullah Bereket
Abdullah Bereket
FDFeyza Darendeliler
Feyza Darendeliler
FBFirdevs Baş
Firdevs Baş
ŞPŞükran Poyrazoğlu
Şükran Poyrazoğlu
CBCarolyn Bondy
Carolyn Bondy
Turner syndrome (TS) is a chromosomal disorder caused by complete or partial X chromosome monosomy that manifests various clinical features depending on the karyotype and on the genetic background of affected girls. This study aimed to systematically investigate the key clinical features of TS in relationship to karyotype in a large pediatric Turkish patient population. Our retrospective study included 842 karyotype-proven TS patients aged 0-18 years who were evaluated in 35 different centers in Turkey in the years 2013-2014. The most common karyotype was 45,X (50.7%), followed by 45,X/46,XX (10.8%), 46,X,i(Xq) (10.1%) and 45,X/46,X,i(Xq) (9.5%). Mean age at diagnosis was 10.2±4.4 years. The most common presenting complaints were short stature and delayed puberty. Among patients diagnosed before age one year, the ratio of karyotype 45,X was significantly higher than that of other karyotype groups. Cardiac defects (bicuspid aortic valve, coarctation of the aorta and aortic stenosis) were the most common congenital anomalies, occurring in 25% of the TS cases. This was followed by urinary system anomalies (horseshoe kidney, double collector duct system and renal rotation) detected in 16.3%. Hashimoto's thyroiditis was found in 11.1% of patients, gastrointestinal abnormalities in 8.9%, ear nose and throat problems in 22.6%, dermatologic problems in 21.8% and osteoporosis in 15.3%. Learning difficulties and/or psychosocial problems were encountered in 39.1%. Insulin resistance and impaired fasting glucose were detected in 3.4% and 2.2%, respectively. Dyslipidemia prevalence was 11.4%. This comprehensive study systematically evaluated the largest group of karyotype-proven TS girls to date. The karyotype distribution, congenital anomaly and comorbidity profile closely parallel that from other countries and support the need for close medical surveillance of these complex patients throughout their lifespan.

5 March 2014 in Journal of Clinical Research in Pediatric Endocrinology
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Journal Article
Open access
ETEmel Torun
Emel Torun
İÖİlker Tolga Özgen
İlker Tolga Özgen
SGSelim Gökçe
Selim Gökçe
SASinem Aydın
Sinem Aydın
YCYaşar Cesur
Yaşar Cesur
We aimed to determine the association of thyroid functions with the components of metabolic syndrome (MS) and non-alcoholic fatty liver disease (NAFLD) in pediatric obese patients. The study included 109 obese children (aged 9-15 years) and a control group of 44 healthy age and gender-matched children of normal weight. NAFLD was diagnosed by conventional ultrasound examination. We assessed the anthropometric data and serum biochemical parameters including lipid profile, alanine aminotransferase (ALT), fasting glucose and insulin levels and thyroid stimulating hormone (TSH), free thyroxine (fT4) and free triiodothyronine (fT3) levels. The homeostasis model assessment of insulin resistance (HOMA-IR) was calculated as a measure of IR. The mean age and gender distributions in the groups were similar (p=0.23). The mean body mass index (BMI) z-scores of obese children with grade 2-3 NAFLD were significantly higher than those of the obese children without hepatic steatosis (p<0.001). Mean ALT, triglyceride (TG) and LDL cholesterol increased and HDL-cholesterol significantly decreased as the hepatic steatosis increased (p<0.05). HOMA-IR levels in obese subjects with grade 2-3 NAFLD were significantly higher than those in both obese children without NAFLD and grade 1 NADFL (p=0.05 and 0.001, respectively). In the obese subjects, TSH levels were increased significantly as the degree of steatosis increased (p=0.04) but fT3 and fT4 levels were not different. In correlation analysis, TSH was significantly correlated with ALT, BMI SDS and the degree of steatosis. Obese children demonstrate an increase in TSH levels as the degree of steatosis increased.

27 March 2013 in International Journal of Endocrinology
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Journal Article
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ETEmel Torun
Emel Torun
EGErdem Gönüllü
Erdem Gönüllü
İÖİlker Tolga Özgen
İlker Tolga Özgen
ECErgül Cindemir
Ergül Cindemir
FÖFaruk Öktem
Faruk Öktem
Objectives. We aimed to determine the relationship between insulin resistance and serum 25-hydroxyvitamin D (25-OHD) levels in obese children and their nonobese peers.Materials and Methods. Included in the study group were 188 obese children (aged 9–15 years), and 68 age- and gender-matched healthy children of normal weight as control group. Anthropomorphic data were collected on patients and fasting serum glucose, insulin, serum lipids, alanine aminotransaminase (ALT) and 25-OHD were measured. The homeostatic model assessment of insulin resistance (HOMA-IR) was calculated in both groups.Results. The levels of 25-OHD in the obese group were significantly lower than those of the nonobese (). HOMA-IR, triglycerides, low-density lipoprotein, and ALT levels in the obese group were significantly higher than values of control group ( and , resp.). In the obese group, vitamin D deficiency, insufficiency, and sufficiency (25-OHD < 10 ng/dl, < 20, >10 ng/dl; > 20 ng/dl, resp.) were not correlated with HOMA-IR (, ). HOMA-IR was negatively correlated with BMI, BMI SDS, and BMI%, and triglycerides, low-density lipoprotein, and ALT levels ().Conclusion. The insulin resistance of the obese subjects who were vitamin D deficient and insufficient did not statistically differ from those with vitamin D sufficiency. Low 25-hydroxyvitamin D levels were not related with higher insulin resistance in obese children and adolescents. In obese subjects, insulin resistance was affected more from BMI, BMI SDS, and BMI% than from 25-hydroxyvitamin D levels.

1 September 2016 in Journal of Clinical Research in Pediatric Endocrinology
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Journal Article
Open access
ZSZeynep Siklar
Zeynep Siklar
MGMikayir Genens
Mikayir Genens
ŞPŞükran Poyrazoğlu
Şükran Poyrazoğlu
FBFirdevs Baş
Firdevs Baş
FDFeyza Darendeliler
Feyza Darendeliler
MBMerih Berberoğlu
Merih Berberoğlu
Noonan syndrome (NS) is a multisystem disorder, and short stature is its most striking manifestation. Optimal growth hormone (GH) treatment for NS is still controversial. In this study, using a nationwide registration system, we aimed to evaluate the growth characteristics and the clinical features of NS patients in Turkey and their growth response to GH treatment. Children and adolescents with a diagnosis of NS were included inthe study. Laboratory assessment including standard GH stimulation test results were evaluated. Height increment of patients with or without GH treatment were analyzed after three years of therapy. A total of 124 NS patients from different centers were entered in the web-based system. Short stature and typical face appearance were the most frequently encountered diagnostic features of our patients. Of the 84 patients who were followed long-term, 47 hadreceived recombinant human GH (rhGH). In this group of 47 patients, height standard deviation score (HSDS) increased from -3.62±1.14 to -2.85±0.96 after three years of therapy, indicating significant differences from the patients who did not receive GH treatment. PTPN11 gene was analyzed in 61 patients, and 64% of these patients were found to have a mutation. HSDS at admission was similar in patients with or without PTPN11 gene mutation. A diagnosis of NS should be kept in mind in all patients with short stature showing systemic clinical findings. GH therapy is effective for improvement of short stature especially in the first two years of treatment. Further studies are needed for optimisation of GH therapy and evaluation of final height data in NS patients.