title: Genetic associations of psoriasis in a Pakistani population.
abstract: BACKGROUND
  Genetic predisposition to psoriasis, an inflammatory skin disease affecting 0·2-4% of the world population, is well established. Thus far, 41 psoriasis susceptibility loci reach genome-wide significance (P ≤ 5 × 10(-8) ). Identification of genetic susceptibility loci in diverse populations will help understand the underlying biology of psoriasis susceptibility.
  
  
  OBJECTIVE
  The primary objective of this study was to examine psoriasis susceptibility associations previously reported in Chinese and caucasian populations in a Pakistani cohort.
  
  
  METHODS
  Blood samples and phenotype data were collected from psoriasis cases and controls in Islamabad, Pakistan. DNA was isolated and genotypes of selected susceptibility markers were determined. The data were analysed using χ(2) tests or logistic regression for psoriasis association.
  
  
  RESULTS
  HLA-Cw6 showed the strongest association [odds ratio (OR) 2·43, P = 2·3 × 10(-12) ]. HLA-Cw1 showed marginally significant association (OR 1·66, P = 0·049), suggesting that the HLA-Cw1-B46 risk haplotype may be present in the Pakistani population. Three other loci (IL4/IL13, NOS2, TRAF3IP2) showed nominally significant association (P < 0·05).
  
  
  CONCLUSIONS
  HLA-Cw6 is strongly associated with psoriasis susceptibility in the Pakistani population, as has been found in every other population studied. In addition, HLA-Cw1 showed marginal association, reflecting the relative geographical proximity and thus likely genetic relatedness to other populations in which the HLA-Cw1-B46 haplotype is known to be associated. A larger cohort and a denser marker set will be required for further analysis of psoriasis associations in the South Asian population.
authors.affiliation: PMAS-Arid Agriculture University Rawalpindi, Rawalpindi, Pakistan.
authors.forename: P A
authors.initials: PA
authors.lastname: Shaiq
authors.forename: P E
authors.initials: PE
authors.lastname: Stuart
authors.forename: A
authors.initials: A
authors.lastname: Latif
authors.forename: C
authors.initials: C
authors.lastname: Schmotzer
authors.forename: A H
authors.initials: AH
authors.lastname: Kazmi
authors.forename: M S
authors.initials: MS
authors.lastname: Khan
authors.forename: M
authors.initials: M
authors.lastname: Azam
authors.forename: T
authors.initials: T
authors.lastname: Tejasvi
authors.forename: J J
authors.initials: JJ
authors.lastname: Voorhees
authors.forename: G K
authors.initials: GK
authors.lastname: Raja
authors.forename: J T
authors.initials: JT
authors.lastname: Elder
authors.forename: R
authors.initials: R
authors.lastname: Qamar
authors.forename: R P
authors.initials: RP
authors.lastname: Nair
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D000328:Adult; D017668:Age of Onset; D005260:Female; D056426:Genetic Loci / Q000235:genetics*; D020022:Genetic Predisposition to Disease / Q000235:genetics; D055106:Genome-Wide Association Study; D005838:Genotype; D015236:HLA-C Antigens / Q000235:genetics; D006239:Haplotypes; D006801:Humans; D018793:Interleukin-13 / Q000235:genetics; D008297:Male; D052247:Nitric Oxide Synthase Type II / Q000235:genetics; D010154:Pakistan / Q000208:ethnology; D020641:Polymorphism, Single Nucleotide; D011565:Psoriasis / Q000235:genetics*; D047988:Tumor Necrosis Factor Receptor-Associated Peptides and Proteins / Q000235:genetics
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D015236:HLA-C Antigens; C528994:HLA-C*06 antigen; C047431:HLA-Cw1 antigen; D018793:Interleukin-13; C414202:TRAF3IP2 protein, human; D047988:Tumor Necrosis Factor Receptor-Associated Peptides and Proteins; C496319:NOS2 protein, human; D052247:Nitric Oxide Synthase Type II