Psoriasis Susceptibility Locus on 18p Revealed by Genome Scan in Finnish Families Not Associated with PSORS1

• Published in: Journal of investigative dermatology Vol. 121; no. 4; pp. 735 - 740
• Main Authors: Asumalahti, Kati, Laitinen, Tarja, Lahermo, Päivi, Suomela, Sari, Itkonen-Vatjus, Raija, Jansen, Christer, Karvonen, Jaakko, Karvonen, Seija-Liisa, Reunala, Timo, Snellman, Erna, Uurasmaa, Tutta, Saarialho-Kere, Ulpu, Kere, Juha
• Format: Journal Article
• Language: English
• Published: Danvers, MA Elsevier Inc 01.10.2003; Nature Publishing; Elsevier Limited
• Subjects: Adolescent; Adult; Aged; Aged, 80 and over; Biological and medical sciences; Child; Chromosome Mapping; Chromosomes, Human, Pair 18; Dermatology; Family Health; Female; Finland; Genetic Linkage; genetic mapping; Genetic Predisposition to Disease; Genome, Human; Humans; linkage analysis; Male; Medical sciences; Medicin och hälsovetenskap; Middle Aged; multifactorial disease; Pedigree; Psoriasis - genetics; Psoriasis. Parapsoriasis. Lichen; skin; Europe; Finland; skin; genetic mapping; linkage analysis; multifactorial disease; Human; Skin disease; Chromosome E18; Psoriasis; Family study; Genetic linkage; Genetics; Locus; multifactorial disease/genetic mapping/ linkage analysis/skin
• ISSN: 0022-202X; 1523-1747
• DOI: 10.1046/j.1523-1747.2003.12483.x

The major susceptibility locus for psoriasis, PSORS1, resides on chromosome 6p and includes the candidate genes HLA-C, HCR, and CDSN. Based on a nationwide collection of psoriasis patients and genotyping for the PSORS1 susceptibility haplotype, we selected for a genome scan nine families who do not show association with PSORS1 to more easily detect minor loci for psoriasis susceptibility. In the genome scan, five loci gave initial evidence of linkage and were studied with a denser marker map. After fine mapping, only one locus on 18p11.23 showed suggestive evidence of linkage (nonparametric multipoint linkage analysis score, 3.58; p=0.0038). The bootstrapping analysis showed that one large family contributed the majority of the linkage (p=0.0039), but was supported by other families. Haplotype sharing between the linked families and haplotype association analysis gave additional support for the locus. Further, the 18p locus has shown nominal evidence of linkage with psoriasis in the British population. Taken together, these findings confirm the presence of a minor susceptibility locus for psoriasis on 18p11.