title: Follow-up analysis of 180 Chinese Han families: identification of a novel locus for psoriasis at 2p22.3-11.2.
abstract: BACKGROUND
  Psoriasis is a common inflammatory and hyperproliferative skin disease. The pathogenesis of psoriasis remains obscure. Family and twin studies have suggested a strong genetic susceptibility to psoriasis. Eight linkage loci (PSORS1-7, PSORS9) were identified and accepted by the OMIM and an additional 16 susceptibility loci have been suggested so far.
  
  
  OBJECTIVE
  To investigate further three suggested psoriasis susceptibility loci at 2p22.3-11.2, 13q21-32 and 17q22-25.3 in a Chinese population. Using an expanded sample of 180 Chinese families with psoriasis and improved marker coverage, we verified whether they were Chinese Han psoriasis susceptibility loci.
  
  
  METHODS
  In total, 180 Chinese Han families with psoriasis vulgaris (including the 61 families used in the original genome-wide scan and 119 new families) were recruited from the Dermatology Department at the First Hospital Affiliated to Anhui Medical University. Two-point and multipoint parametric and nonparametric linkage (NPL) analyses were performed at 2p, 13q and 17q in the total 180 families as well as the 61 original and 119 new families separately.
  
  
  RESULTS
  At the region 2p, a maximum multipoint NPL score of 4.11 was identified at locus D2S337 (P=0.000003), and a maximum multipoint heterogeneity LOD (HLOD) score of 4.93 (alpha=54%) was identified at the same locus in the analysis of the 180 families. However, the analysis of the 180 families did not identify any significant linkage evidence at the region 13q21-32 [a maximum multipoint HLOD score of 0.10 (alpha=7%) and NPL score of 0.95 (P=0.14)] or the region 17q22-25.3 [a maximum multipoint HLOD score of 0.08 (alpha=6%) and NPL value of 0.94 (P=0.14)]. For these two regions, the LOD scores from the 180 families as well as the 119 new families were much smaller than the ones obtained from the original 61 families.
  
  
  CONCLUSIONS
  Our study indicates that 2p22.3-11.2 is a novel psoriasis susceptibility locus in the Chinese Han population and confirms that psoriasis is a genetically heterogeneous disease.
authors.affiliation: Institute of Dermatology & Department of Dermatology at No. 1 Hospital, Anhui Medical University, 69 Meishan Road, Hefei, Anhui 230032, China.
authors.forename: L D
authors.initials: LD
authors.lastname: Sun
authors.forename: S
authors.initials: S
authors.lastname: Yang
authors.forename: J J
authors.initials: JJ
authors.lastname: Liu
authors.forename: Y Q
authors.initials: YQ
authors.lastname: Ren
authors.forename: X
authors.initials: X
authors.lastname: Fan
authors.forename: S X
authors.initials: SX
authors.lastname: Xu
authors.forename: L
authors.initials: L
authors.lastname: Zhou
authors.forename: C J
authors.initials: CJ
authors.lastname: Yang
authors.forename: F L
authors.initials: FL
authors.lastname: Xiao
authors.forename: M
authors.initials: M
authors.lastname: Gao
authors.forename: Y
authors.initials: Y
authors.lastname: Cui
authors.forename: W H
authors.initials: WH
authors.lastname: Du
authors.forename: W
authors.initials: W
authors.lastname: Huang
authors.forename: X J
authors.initials: XJ
authors.lastname: Zhang
mesh_terms: D000293:Adolescent; D000328:Adult; D017668:Age of Onset; D000368:Aged; D000369:Aged, 80 and over; D044466:Asian People / Q000235:genetics*; D002648:Child; D002675:Child, Preschool; D002681:China / Q000453:epidemiology; D002877:Chromosomes, Human / Q000235:genetics*; D004198:Disease Susceptibility / Q000453:epidemiology / Q000276:immunology; D005260:Female; D005500:Follow-Up Studies; D008040:Genetic Linkage; D005838:Genotype; D006801:Humans; D007223:Infant; D008297:Male; D008875:Middle Aged; D010375:Pedigree; D011565:Psoriasis / Q000209:etiology / Q000235:genetics* / Q000276:immunology; D040641:Quantitative Trait Loci / Q000235:genetics*