title: Genome-wide linkage scan for psoriasis susceptibility loci in multiplex Tunisian families.
abstract: BACKGROUND
  Psoriasis is a relapsing chronic inflammatory skin disease affecting all population groups, with a peak prevalence of 3% in northern European and Scandinavian caucasians. Epidemiological studies have implicated a genetic component to psoriasis. In the past 12 years multiple genome-wide linkage analyses have identified putative susceptibility loci on several chromosomes, with a major locus in the major histocompatibility complex region.
  
  
  OBJECTIVE
  To investigate the genetic basis of familial psoriasis in the Tunisian population using a genome-wide linkage scan in seven ultiplex psoriatic families from Tunisia.
  
  
  METHODS
  Following single nucleotide polymorphism (SNP) genotyping on the Affymetrix 10K SNP array, we performed nonparametric linkage (NPL) multipoint analyses to identify genotypes and obtain evidence for linkage with psoriasis across the genome.
  
  
  RESULTS
  No chromosomal region gave consistent evidence for linkage, providing evidence for genetic heterogeneity in Tunisian psoriasis families. Significant evidence for linkage of psoriasis to chromosome 2p12 was seen in one family. We also identified several regions of tentative psoriasis linkage on chromosomes 2q, 4q, 6p, 11q, 12q, 9q and 13q. One family exhibiting suggestive evidence for linkage to 17q25 (PSORS2) was identified and all affected members harboured a p.Gly117Ser mutation in CARD14 (caspase recruitment domain family, member 14), recently reported to lead to psoriasis in a large family from the U.S.A.
  
  
  CONCLUSIONS
  Our results support the genetic heterogeneity of psoriasis in the Tunisian population, provide confirmatory evidence for a novel psoriasis locus at chromosome 2p12 and reveal a psoriasis family with a mutation at PSORS2.
authors.affiliation: Département de Biologie, Laboratoire de Génétique, Immunologie et Pathologie Humaine, Faculté des Sciences de Tunis, Tunis, Tunisia.
authors.forename: M
authors.initials: M
authors.lastname: Ammar
authors.forename: C
authors.initials: C
authors.lastname: Bouchlaka-Souissi
authors.forename: C A
authors.initials: CA
authors.lastname: Helms
authors.forename: I
authors.initials: I
authors.lastname: Zaraa
authors.forename: C T
authors.initials: CT
authors.lastname: Jordan
authors.forename: H
authors.initials: H
authors.lastname: Anbunathan
authors.forename: R
authors.initials: R
authors.lastname: Bouhaha
authors.forename: S
authors.initials: S
authors.lastname: Kouidhi
authors.forename: N
authors.initials: N
authors.lastname: Doss
authors.forename: R
authors.initials: R
authors.lastname: Dhaoui
authors.forename: A
authors.initials: A
authors.lastname: Ben Osman
authors.forename: A
authors.initials: A
authors.lastname: Ben Ammar El Gaied
authors.forename: R
authors.initials: R
authors.lastname: Marrakchi
authors.forename: M
authors.initials: M
authors.lastname: Mokni
authors.forename: A M
authors.initials: AM
authors.lastname: Bowcock
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D053468:CARD Signaling Adaptor Proteins; D002648:Child; D002889:Chromosomes, Human, Pair 2 / Q000235:genetics*; D005260:Female; D008040:Genetic Linkage / Q000235:genetics; D020022:Genetic Predisposition to Disease / Q000235:genetics*; D015894:Genome, Human / Q000235:genetics; D055106:Genome-Wide Association Study; D005838:Genotype; D006162:Guanylate Cyclase; D006801:Humans; D008297:Male; D008565:Membrane Proteins; D008875:Middle Aged; D010375:Pedigree; D020641:Polymorphism, Single Nucleotide / Q000235:genetics*; D011506:Proteins / Q000235:genetics*; D011565:Psoriasis / Q000235:genetics*; D014416:Tunisia; D055815:Young Adult
chemical_list: D053468:CARD Signaling Adaptor Proteins; D008565:Membrane Proteins; D011506:Proteins; C426243:CARD14 protein, human; D006162:Guanylate Cyclase