Person: POLAT, HAMZA
Loading...
Email Address
Birth Date
Research Projects
Organizational Units
Job Title
Last Name
POLAT
First Name
HAMZA
Name
6 results
Search Results
Now showing 1 - 6 of 6
Publication Metadata only The use of long-range pcr protocol in the diagnosis of friedreich ataxia(2020-11-22) ALAVANDA, CEREN; POLAT, HAMZA; SÖYLEMEZ, MEHMET ALİ; GEÇKİNLİ, BİLGEN BİLGE; ATA, PINAR; ARMAN, AHMET; ALAVANDA C., POLAT H., DEMİR Ş., ARSLAN ATEŞ E., SÖYLEMEZ M. A., GEÇKİNLİ B. B., ATA P., ARMAN A.Introduction: Friedreich ataxia(FRDA) is multisystemic disorder characterized by trinucleotide expansions in FXN gene. It’s one of the most common causes of autosomal recessive ataxia. Material/Method: Fragment analysis method was used to detect GAA triple nucleotide repeat expansions in the first intron of the FXN gene. Long-range PCR was performed with primers selected from both in intron and exon for confirmation in patients with more than two hundred repeats. Results: Fragment analysis was performed in 20 patients with FRDA pre-diagnosis. Long-range PCR was performed in 5 patients with more than 200 GAA repeats. After long-range PCR, the number of repetitions between 180 and 1450 was found in these patients. One allele of two siblings whose fragment analysis gave negative results was found to have an approximately 950 repeats. FXN gene sequence analysis was planned in order not to miss point mutations in patients with negative results. In order to provide appropriate genetic counseling to patients, segregation studies are continuing. Discussion: Although fragment analysis is reliable method in this disease, its reliability decreases when the number of repeats is high. Although Southern-blot method can be used for confirmation, long-range PCR protocols which are cheaper and easier, can also be applied.Publication Metadata only Pelizaeus-merzbacher-benzeri hastalık: GJC 2 gen mutasyonlu pediatrik bir olguda manyetik rezonans görüntüleme bulguları(2021-10-31) YAPICI, ÖZGE; POLAT, HAMZA; ÇİMŞİT, NURİ ÇAGATAY; YAPICI Ö., ALMUS E., ASLAN B., POLAT H., ÖZTÜRK G., ÇİMŞİT N. Ç.Giriş-Amaç: Pelizaeus-Merzbacher benzeri hastalık (PMBH), bir gap-junction proteini olan connexin’i (Cx47) kodlayan GJC2 genindeki mutasyonların neden olduğu otozomal resesif bir hastalıktır (1). PMLD, X’e bağlı Pelizaeus-Merzbacher hastalığı (PMH) ile aynı klinik ve radyolojik özellikleri paylaşır, ancak PMH’da beklendiği gibi PLP1 geninde bir mutasyon yoktur. Manyetik Rezonans Görüntüleme (MRG)’de hipomiyelinasyon ile, klinik açıdan ise erken başlangıçlı nistagmus, gecikmiş motor kilometre taşları, progresif spastisite ve ataksi ile karakterizedir (1,2). Burada, GJC 2 gen mutasyonuna sahip 22 aylık bir erkek çocuğunun MRG bulgularını sunuyoruz. Olgu Sunumu: 22 aylık erkek bebek, konuşma ve motor disfonksiyonu şikayetleri ile kranial MRG için radyoloji bölümüne sevk edildi. Fizik muayenesinde bilateral nistagmus ve görme kaybı mevcuttu. Geçmiş klinik öyküsünde 38. gebelik haftasında 2. derece akraba evliliğinden sezaryen ile doğduğu öğrenildi. 6. ayda başını tutma, 9. ayda desteksiz oturma, 12. ayda emekleme yeteneğine sahipken desteksiz yürüyebilme yeteneği hiç gelişmemişti. Kraniyal MRG’de, subkortikal ve periventriküler beyaz cevherde, internal ve eksternal kapsüllerde, beyin sapı ve korpus kallozumda T2 ağırlıklı görüntülerde (T2AG) simetrik hiperintensite izlendi (Şekil 1). T1 ağırlıklı görüntülerde (T1AG) serebrum ve serebellum’da gri ve beyaz cevher arasındaki ayrımın kaybolması, hipomyelinasyon ile uyumlu olarak değerlendirildi(Şekil 2). Sentrum semiovale, korpus kallozum ve mezensefalonun bazı kısımlarında T1AG’de hafif hiperintensite görülmesi bu düzeylerde az da olsa miyelinasyonun gerçekleştiğini düşündürmekte idi (Şekil 2). MRG’yi takiben genetik test için sevk edilen olgunun, homozigot GJC2 mutasyonuna sahip olduğu bulundu. TartışmaSonuç: PMBH, PMH’dakine benzer şekilde, beyinde miyelin birikiminin kalıcı kaybına bağlı klinik olarak nistagmus, serebellar ataksi ve spastisite ile karakterizedir (3). PMH’nın aksine PMBH’de semptomlar daha yavaş ilerler, kognitif fonksiyonlar daha çok korunur ve MRG’de kortikospinal traktların parsiyel miyelinasyonu görülür (3). PMBH olgularında, PMH ile benzer şekilde, kranial MRG’de serebral beyaz cevherde homojen T2 hiperintensite şeklinde prezente olan yaygın hipomiyelinasyon paterni görülür (2). Kortikospinal yolların değişken miyelinasyonu ile birlikte, pons’un T2 hiperintensitesi tipiktir. Olgumuzda gözlemlediğimiz gibi iç kapsülün arka bacağında kısmi miyelinasyon da bildirilmiştir (1,3). Olgumuzda olduğu gibi, serebellar beyaz cevher, korunmuş hacmi ile daha az etkilenebilir. Bazal ganglionlar ve talamus genellikle normaldir (1). Olgumuzun tanısı, daha ileri radyolojik inceleme gerektirmeden genetik çalışmalarla konmuştur. PMBH için spesifik bir tedavi yoktur ve tıbbi bakım çoğunlukla destekleyici tedavi ile sınırlıdır (2)Publication Open Access Gamma, charged particle and neutron radiation shielding capacities of ternary composites having polyester/barite/tungsten boride(2023-11-01) POLAT, HAMZA; Akman F., Ozdogan H., Kilicoglu O., Ogul H., Agar O., Kacal M., Polat H., Tursucu A.The presented work investigates the photon, charged particle and neutron radiation shielding performances of polyester-based composites filled with barite and/or tungsten boride by using experimental, theoretical, and Monte Carlo simulation techniques. The amount of barite/tungsten boride varying from 0 wt% to 50 wt% in the material and polyester resin were exploited as filler and base materials, respectively. Experimental evaluation of BaWB composites has been performed with help of an HPGe detector based gamma spectrometer as well as 22Na, 133Ba, 137Cs and 60Co radioactive point sources with energies in the range of 276.4–1332.5 keV. The experimental data were compared to those theoretically calculated in WinXCOM as well as Monte Carlo (MC) simulations, i.e., MCNP6, GEANT4 and FLUKA codes. The obtained mass attenuation coefficients for the produced composites were in good agreement with the results of MC simulations and WinXCOM software. Comparing to the other polymer composite samples, the sample with the maximum tungsten boride weight percentage has the best radiation shielding property because of having the highest attenuation coefficients and lowest absorption thicknesses.Publication Metadata only Secondary findings in 622 Turkish clinical exome sequencing data(SPRINGERNATURE, 2021) ARMAN, AHMET; Ates, Esra Arslan; Turkyilmaz, Ayberk; Yildirim, Ozlem; Alavanda, Ceren; Polat, Hamza; Demir, Senol; Cebi, Alper Han; Geckinli, Bilgen Bilge; Guney, Ahmet Ilter; Ata, Pinar; Arman, AhmetCES (Clinical Exome Sequencing) is a method that we use to diagnose rare diseases with nonspesific clinical features. Besides primary indication for testing genetic information may be detected about diseases which have not yet emerged. ACMG guidelines recommend to report pathogenic variations in medically actionable 59 genes. In this study we evaluated CES data of 622 cases which were tested for various indications. According to ACMG recommendations 59 genes were screened for reportable variations. The detected variations were reviewed using distinct databases and ACMG variation classification guidelines. Among 622 cases 13 (2.1%) had reportable variations including oncogenetic, cardiogenetic disorders, and malignant hyperthermia susceptibility-related genes. In 15 cases (2.4%) heterozygous pathogenic and likely pathogenic variations were detected in genes showing autosomal recessive inheritance. Ten novel variations causing truncated protein or splicing defect were reported. We detected 11 variations having conflicting interpretations in databases and 30 novel variations, predicted as likely pathogenic via insilico analysis tools which further evaluations are needed. As to our knowledge this is the first study investigating secondary findings in Turkish population. To extract the information that may lead to prevent severe morbidities and mortalities from big data is a valuable and lifesaving effort. Results of this study will contrbute to existing knowledge about secondary findings in exome sequencing and will be a pioneer for studies in Turkish population.Publication Metadata only Whole-exome sequencing reveals new potential genes and variants in patients with premature ovarian insufficiency(SPRINGER/PLENUM PUBLISHERS, 2022) ARMAN, AHMET; Turkyilmaz, Ayberk; Alavanda, Ceren; Ates, Esra Arslan; Geckinli, Bilgen Bilge; Polat, Hamza; Gokcu, Mehmet; Karakaya, Taner; Cebi, Alper Han; Soylemez, Mehmet Ali; Guney, Ahmet Ilter; Ata, Pinar; Arman, AhmetPurpose Premature ovarian insufficiency (POI) is a heterogeneous disorder characterized by the cessation of menstrual cycles before the age of 40 years due to the depletion or dysfunction of the ovarian follicles. POI is a highly heterogeneous disease in terms of etiology. The aim of this study is to reveal the genetic etiology in POI patients. Methods A total of 35 patients (mean age: 27.2 years) from 28 different families diagnosed with POI were included in the study. Karyotype, FMR1 premutation analysis, single nucleotide polymorphism (SNP) array, and whole-exome sequencing (WES) were conducted to determine the genetic etiology of patients. Results A total of 35 patients with POI were first evaluated by karyotype analysis, and chromosomal anomaly was detected in three (8.5%) and FMR1 premutation was detected in six patients (17%) from two different families. A total of 29 patients without FMR1 premutation were included in the SNP array analysis, and one patient had a 337-kb deletion in the chromosome 6q26 region including PARK2 gene, which was thought to be associated with POI. Twenty-nine cases included in SNP array analysis were evaluated simultaneously with WES analysis, and genetic variant was detected in 55.1% (16/29). Conclusion In the present study, rare novel variants were identified in genes known to be associated with POI, which contribute to the mutation spectrum. The effects of detected novel genes and variations on different pathways such as gonadal development, meiosis and DNA repair, or metabolism need to be investigated by experimental studies. Molecular etiology allows accurate genetic counseling to the patient and family as well as fertility planning.Publication Open Access Genetic and Clinical Characterization of Patients with Maturity-Onset of Diabetes of the Young (MODY): Identification of Novel Variations(AVES, 2021-09-22) GÜNEY, AHMET İLTER; Ates, Esra Arslan; Ustay, Ozlem; Polat, Hamza; Apaydin, Tugce; Elbasan, Onur; Yildirim, Ozlem; Guney, Ahmet IlterBackground: Maturity-onset diabetes of the young (MODY) is a rare monogenic type of diabetes, and accounts for 2-5% of all diabetes cases. An early age of onset, a family history supporting autosomal-dominant inheritance, insulin resistance, and the absence of autoimmunity are the major characteristics of MODY. However, genetic testing is crucial for diagnosis. Aims: To investigate the 7 MODY-related genes and clinical findings of patients with a preliminary clinical diagnosis of MODY. Study Design: Retrospective cross-sectional study. Methods: In this study, 7 genes (KCNJ11, ABCC8, INS, GCK, HNF4A, HNF1A, and HNF1B) related to MODY were screened via targeted sequencing in 182 cases with a confirmed pre-diagnosis of MODY. The clinical characteristics of the patients were evaluated retrospectively. Results: A total of 182 patients, 48% of whom were women, between the ages of 18-62 were included in the study. In 30 cases (16.4%), 28 different pathogenic variations were found, of which 20 were previously reported and 8 were novel variations segregated by disease within the family. Pathogenic variations were detected in the following genes in order of mutation frequency; GCK, HNF1A, ABCC8, HNF4A, HNF1B and KCNJ11. Interestingly, six of the 30 cases (20%) carried a pathogenic variation in the ABCC8 gene. No mutation was detected in the INS gene. A family history of vertically transmitted diabetes and elevated HbA1C at the time of diagnosis were found in 20 (66%) and 16 (52%) cases, respectively. Conclusion: In this series, 28 different pathogenic variations are identified, 8 of which are novel. The rate of pathogenic variation in the ABCC8 gene is unexpectedly high. Two-thirds of cases have a family history of vertically transmitted diabetes.