diplomsko delo univerzitetnega študijskega programa
Urška Gabor (Author), Uroš Potočnik (Mentor)

Abstract

Kronično vnetno črevesno bolezen (KVČB) lahko razdelimo na dva glavna podtipa, in sicer Crohnovo bolezen (CB) ter ulcerozni kolitis (UK). Študije so pokazale, da poleg okoljskih dejavnikov k razvoju bolezni pomemben delež prispevajo genetski dejavniki. Do sedaj je bilo z genetskimi študijami dokazano le približno 20% dednosti. Znano pa je, da je v patogenezo bolezni vpleteno veliko število polimorfizmov posameznega nukleotida (SNP). V analizi z mikromrežo (»Immunochip«) je bila predhodno izvedena genska tipizacija za približno 200 000 polimorfizmov pri 250 slovenskih bolnikih s KVČB in kontrolno skupino 250 zdravih posameznikov. Rezultat asociacijske analize je na kromosomu 13 prikazal 280 SNP-jev s p vrednostjo p<0,05, katere smo razporedili v 42 neodvisnih lokusov. Pri multiplem testiranju lahko pride do lažno pozitivnih rezultatov. Zato smo za potrditev kandidatnih polimorfizmov v raziskavi izvedli potrditveno asociacijsko analizo na dodatnih bolnikih in zdravih kontrolah. Namen dela je bil ugotoviti ali so izbrani SNP-i povezani s slovensko populacijo bolnikov s kronično vnetnimi črevesnimi boleznimi. V raziskavi smo po analizi rezultatov predhodne analize z mikromrežo izbrali 3 polimorfizme posameznega nukleotida iz neodvisnih lokusov na kromosomu 13 z vrednostmi p<0,02 ter izvedli genotipizacijo s PCR-RFLP metodo na 364 vzorcih bolnikov in 147 vzorcih zdravih kontrol. Rezultate smo skupaj z rezultati analize z mikromrežo preverili z asociacijsko analizo. V študiji smo potrdili asociacije med SNP-jema rs7994531 (p = 0,020) in rs2765724 (p = 0,00042). Alel C za SNP rs7994531 zmanjšuje tveganje za razvoj KVČB, alel C za SNP rs2765724 pa povečuje tveganje za razvoj KVČB. Vpliv obeh je bolj izražen pri bolnikih s CB, statistično najbolj signifikantno povezavo pa smo ugotovili pri skupini bolnikov z refraktorno obliko CB (p = 0,0012 za rs7994531 in p = 0,0000076 za rs2765724). Kljub temu, da imajo posamezni SNP-ji le majhen doprinos k tveganju za KVČB, lahko trdimo, da naši rezultati pomembno prispevajo k razumevanju genetike te bolezni. SNP-ji identificirani in potrjeni v naši študiji bodo morda v prihodnosti služili kot diagnostični ali prognostični biomarkerji in prispevali delček k natančnejši in hitrejši diagnostiki, ter s tem pripomogli k boljši kvaliteti življenja bolnikov.

Keywords

inflammatory bowel disease;restriction fragment length polymorphism;genotypization;association study;

Data

Language: English
Year of publishing:
Source: Maribor
Typology: 2.11 - Undergraduate Thesis
Organization: UM FKKT - Faculty of Chemistry and Chemical Engineering
Publisher: [U. Gabor]
UDC: 577.212.088.6:616.34(043.2)
COBISS: 16643862 Link will open in a new window
Views: 2015
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Other data

Secondary language: Slovenian
Secondary title: Association study for confirmation of dna polymorphism on chromosome 13 previously associated with Slovenian Crohn disease patients using microarray (biochips)
Secondary abstract: Inflammatory bowel disease is usually classified into Crohn's disease (CD) and ulcerative colitis (UC). Studies have reported that in addition to environmental factors genetic factors also contribute an important proportion to the development of the disease. To date genetic studies have only explained approximately 20% of the heritability. However, it is known that a substantial number of single nucleotid polymorphisms (SNP) are involved in the pathogenesis of the disease. A previous microarray (»Immunochip«) analysis performed genotypization for approximately 200 000 polymorphisms in 250 slovenian IBD patients and a control group of 250 healthy individuals. The association analysis result reported 280 SNPs on chromosome 13 with a p value of p<0,05, which we spread into 42 independent loci. Multiple testing can form false positive results. For that reason we conducted a confirmational association analysis on additional patients and healthy controls for the confirmation of candidate polymorphisms. The aim of our study was to determine whether the chosen SNPs are associated with slovenian IBD patients population. Firstly we analyzed the results of the previous microarray study and we selected 3 SNPs from independent loci on chromosome 13 with p values p<0,02 and performed genotypization using PCR-RFLP method in 364 patient samples and 147 samples of healthy controls. We analysed the results by association analysis combined with the results from the microarray analysis. The study succeeded in confirming association between SNPs rs7994531 (p = 0,020) and rs2765724 (p = 0,00042). Allele C for SNP rs7994531 decreases risk for the development of IBD, while allele C for SNPs rs2765724 increases risk for the disease. Influence of both alleles is stronger in patients with Crohn's disease. Statistically most significant association was discovered in the group of patients with refractory Crohn's disease (p = 0,0012 for rs7994531 and p = 0,0000076 for rs2765724). Although individual SNPs have only a small contribution to the risk for IBD, we can say that our results have an important role in understanding the genetics of the disease. SNPs identified and confirmed in our study may be used as diagnostic or prognostic biomarkers in the future and they might contribute a small part to more precise and faster diagnostics, thereby helping to provide a better life quality for IBD patients.
Secondary keywords: kronično vnetna črevesna bolezen;polimorfizem dolžin restrikcijskih fragmentov;genotipizacija;asociacijska študija;
URN: URN:SI:UM:
Type (COBISS): Bachelor thesis/paper
Thesis comment: Univ. v Mariboru, Fak. za kemijo in kemijsko tehnologijo
Pages: X, 54 str.
Keywords (UDC): mathematics;natural sciences;naravoslovne vede;matematika;biological sciences in general;biologija;material bases of life;biochemistry;molecular biology;biophysics;biokemija;molekularna biologija;biofizika;applied sciences;medicine;technology;uporabne znanosti;medicina;tehnika;medical sciences;medicina;pathology;clinical medicine;patologija;klinična medicina;pathology of the digestive system;complaints of the alimentary canal;bolezni prebavil;gastroenterologija;
ID: 1026615