Tyrosine kinase-2 gene polymorphisms are associated with ulcerative colitis and Crohn's disease in Turkish Population.
OBJECTIVE
Inflammatory bowel disease is a group of chronic inflammatory conditions affecting gastrointestinal tract. Lots of genes have been identified resulting in susceptibility to inflammatory bowel disease. Any polymorphism leading to functional modifications in tyrosine kinase-2 may precipitate excessive immune response in the intestinal mucosa. The aim of our study is to investigate the involvement of tyrosine kinase-2 polymorphisms in the patients with inflammatory bowel disease in Turkish population.


METHODS
Four single nucleotide polymorphisms in tyrosine kinase-2 (rs280523, rs2304256, rs280519 and rs280496) were genotyped in 60 Crohn's disease, 151 ulcerative colitis patients and 89 unrelated healthy controls. These polymorphisms were detected by real-time polymerase chain reaction.


RESULTS
The presence of genotype (CC) in rs2304256 and (AA) in rs280519 were found to increase the susceptibility to ulcerative colitis (P=0.024, 0.025, respectively). rs2304256 (CA) and rs280519 (AG) have provided protection against ulcerative colitis (P=0.021, 0.012, respectively). rs280519 (AG) was protective against Crohn's disease (P=0.045). rs2304256 (CC) increased the susceptibility to inflammatory Crohn's disease (P=0.014). The presence of rs2304256 (A) increased the susceptibility to perianal Crohn's disease (P=0.03). Both rs280519 and rs2304256 polymorphisms were associated with the requirement of corticosteroid and immunosuppressive therapy in ulcerative colitis.


CONCLUSIONS
This study is the first demonstration of the single marker association of tyrosine kinase-2 polymorphisms with ulcerative colitis and Crohn's disease in Turkish population. They may be effective in the etiology of inflammatory bowel disease in our population. Disparity between our study and others may be related to ethnic differences.
Department of Gastroenterology, Abant İzzet Baysal University Faculty of Medicine, Gölköy, 14280 Bolu, Turkey. Electronic address: dr_guraycan@yahoo.com.
Güray
G
Can
Department of Gastroenterology, Trakya University Faculty of Medicine, Edirne, Turkey. Electronic address: atezel22@ttmail.com.
Ahmet
A
Tezel
Department of Genetics, Trakya University Faculty of Medicine, Edirne, Turkey. Electronic address: dr_hakangurkan@yahoo.de.
Hakan
H
Gürkan
Department of Internal Medicine, Abant İzzet Baysal University Faculty of Medicine, Bolu, Turkey. Electronic address: yailaslan@yahoo.com.
Hatice
H
Can
Department of Gastroenterology, Bolu İzzet Baysal State Hospital, Bolu, Turkey. Electronic address: yilmazb76@mynet.com.
Bülent
B
Yılmaz
Department of Gastroenterology, Trakya University Faculty of Medicine, Edirne, Turkey. Electronic address: gulunsal22@yahoo.com.
Gülbin
G
Ünsal
Department of Gastroenterology, Trakya University Faculty of Medicine, Edirne, Turkey. Electronic address: alrsoylu@yahoo.com.
Ali Rıza
AR
Soylu
Department of Gastroenterology, Trakya University Faculty of Medicine, Edirne, Turkey. Electronic address: hasanumit@hotmail.com.
Hasan Celalettin
HC
Ümit
D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D003093:Colitis, Ulcerative / Q000235:genetics*; D003424:Crohn Disease / Q000235:genetics*; D005260:Female; D020022:Genetic Predisposition to Disease; D005838:Genotype; D006801:Humans; D008297:Male; D008875:Middle Aged; D020641:Polymorphism, Single Nucleotide; D060888:Real-Time Polymerase Chain Reaction; D053634:TYK2 Kinase / Q000235:genetics*; D014421:Turkey; D055815:Young Adult
D053634:TYK2 Kinase; C070139:TYK2 protein, human