A study of candidate genes for psoriasis near HLA-C in Chinese patients with psoriasis.
BACKGROUND
Genetic analyses have identified the HLA-Cw6 allele as the major risk allele for psoriasis in many racial groups. However, by serological typing, HLA-Cw6 is not considered a risk factor in Chinese psoriatics. There are several susceptibility genes for psoriasis residing in chromosome 6p near the HLA-C locus, including the corneodesmosin (CDSN) gene, the octamer transcription factor-3 (POU5F1) gene, the major histocompatibility complex class I chain-related gene A (MICA), and the gene for tumour necrosis factor (TNF)-alpha. However, the information about their role in psoriasis in Chinese patients is limited.


OBJECTIVE
We aimed to determine whether Cw6 and the genetic polymorphism of the CDSN gene, POU5F1 gene, MICA gene and the gene for TNF-alpha promoter region were associated with an increased risk of psoriasis in Chinese patients.


METHODS
We conducted a case-control association study in 105 Chinese patients with psoriasis vulgaris and 160 control subjects of similar ages. Genotypes of Cw6, the CDSN gene, the POU5F1 gene, and the gene for the TNF-alpha promoter region were determined by polymerase chain reaction (PCR) followed by restriction enzyme digestion. Genotyping of MICA was determined by PCR combined with fluorescent-based automated fragment detection technology. Results The allele frequencies showed no differences between patients and controls for the POU5F1 gene, MICA gene and the gene for TNF-alpha promoter region. The frequency of the HLA-Cw6 allele in the psoriasis group was significantly higher than that in the control group (18.6% vs. 6.56%, P < 0.00005). For the CDSN gene, patients were more likely to have C allele at position +619 (P = 0.006) and C allele at position +1243 (P = 0.007), but the significance disappeared after correction for multiple testing (Pc > 0.05).


CONCLUSIONS
HLA-Cw6 remains the most significant susceptibility gene in Chinese patients with psoriasis. However, the role of the CDSN gene in the pathogenesis of psoriasis deserves further scrutiny.
Chang
Y T
YT
Department of Dermatology, Taipei Veterans General Hospital and National Yang-Ming University, Taiwan, Republic of China.
Tsai
S F
SF
Lee
D D
DD
Shiao
Y M
YM
Huang
C Y
CY
Liu
H N
HN
Wang
W J
WJ
Wong
C K
CK
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D002681:China / Q000208:ethnology; D004268:DNA-Binding Proteins / Q000235:genetics; D005260:Female; D005838:Genotype; D006023:Glycoproteins / Q000235:genetics; D015236:HLA-C Antigens / Q000235:genetics*; D015395:Histocompatibility Antigens Class I / Q000235:genetics; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins; D008297:Male; D008875:Middle Aged; D050814:Octamer Transcription Factor-3; D011565:Psoriasis / Q000235:genetics*; D012307:Risk Factors; D013624:Taiwan / Q000208:ethnology; D014157:Transcription Factors / Q000235:genetics; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics
C109656:CDSN protein, human; D004268:DNA-Binding Proteins; D006023:Glycoproteins; D015236:HLA-C Antigens; C528994:HLA-C*06 antigen; D015395:Histocompatibility Antigens Class I; D036341:Intercellular Signaling Peptides and Proteins; C099187:MHC class I-related chain A; D050814:Octamer Transcription Factor-3; C494173:POU5F1 protein, human; D014157:Transcription Factors; D014409:Tumor Necrosis Factor-alpha