Vol.19 No.4

Original Article

Lack of association between tyrosine kinase 2 (TYK2) gene polymorphisms and susceptibility to SLE in a Japanese population

Authors

Chieko Kyogoku1 , Akio Morinobu1 , Kunihiro Nishimura2 , Daisuke Sugiyama2 , Hiroshi Hashimoto3 , Yoshiaki Tokano3 , Tsuneyo Mimori4 , Chikashi Terao4 , Fumihiko Matsuda5 , Takayoshi Kuno6 , Shunichi Kumagai1

  • Department of Clinical Pathology and Immunology, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo-ku, Kobe Hyogo, 650-0017, Japan
  • Department of Evidence-based Laboratory Medicine, Kobe University Graduate School of Medicine, Kobe, Japan
  • Department of Internal Medicine and Rheumatology, Juntendo University School of Medicine, Tokyo, Japan
  • Department of Rheumatology and Clinical Immunology, Kyoto University Graduate School of Medicine, Kyoto, Japan
  • Center for Genomic Medicine, Kyoto University Graduate School of Medicine, Kyoto, Japan
  • Division of Molecular Pharmacology and Pharmacogenomics, Department of Biochemistry and Molecular Biology, Kobe University Graduate School of Medicine, Kobe, Japan
Received:

24 February 2009

Accepted:

31 March 2009

Published online:

8 May 2009

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Abstract

Tyrosine kinase 2 (TYK2) is a type I interferon (IFN) signaling pathway gene and was previously reported to be a risk factor for systemic lupus erythematosus (SLE) in Caucasian populations. In order to test for its genetic association with SLE in a Japanese population, TYK2 single nucleotide polymorphisms (SNPs), rs2304256, rs12720270 and rs280519, were genotyped. A case-control association study was performed in a total of 411 Japanese SLE patients and 467 healthy controls. Linkage disequilibrium (LD) among TYK2 SNPs was examined. According to the data from 94 healthy controls, non-synonymous rs2304256 resulting in Val → Phe substitution was revealed to be in a LD with rs12720270 and rs280519. Therefore, we further genotyped rs2304256 as a tag SNP in the full sample sets. As a result, no differences in genotype distribution and allelic frequencies of rs2304256 were found between SLE patients and healthy controls. In conclusion, TYK2 is not a genetic risk factor for SLE in a Japanese population. Our result suggests that there is an ethnic difference in the susceptibility genes for SLE.

Key words

Systemic lupus erythematosus (SLE) - Tyrosine kinase 2 (TYK2) - Single nucleotide polymorphism (SNP) - Type I interferon (IFN) signaling pathway - Association study