A susceptibility gene for psoriatic arthritis maps to chromosome 16q: evidence for imprinting.
Several genetic loci have been reported for psoriasis, but none has been specifically linked to psoriatic arthritis (PsA), a condition that affects >10% of patients with psoriasis. A genetic component for PsA is suggested by segregation within families and high concordance among identical twins. We performed a linkage scan to map genes contributing to PsA. We identified 178 patients with PsA out of 906 patients who were included in our genetic study of psoriasis. Using a comprehensive genealogy database, we were able to connect 100 of these into 39 families. We genotyped the patients using a framework marker set of 1,000 microsatellite markers, with an average density of 3 cM, and performed multipoint, affected-only, allele-sharing linkage analysis using the Allegro program. On the basis of the initial results, we genotyped more markers for the most prominent loci. A linkage with a LOD score of 2.17 was observed on chromosome 16q. The linkage analysis, conditioned on paternal transmission to affected individuals, gave a LOD score of 4.19, whereas a LOD score of only 1.03 was observed when conditioned for maternal transmission. A suggestive locus on chromosome 16q has previously been implicated in psoriasis. Our data indicate that a gene at this locus may be involved in paternal transmission of PsA.
Karason
Ari
A
deCODE Genetics, Reykjavik, Iceland. akarason@decode.is
Gudjonsson
Johann E
JE
Upmanyu
Ruchi
R
Antonsdottir
Arna A
AA
Hauksson
Valdimar B
VB
Runasdottir
E Hjaltey
EH
Jonsson
Hjortur H
HH
Gudbjartsson
Daniel F
DF
Frigge
Michael L
ML
Kong
Augustine
A
Stefansson
Kari
K
Valdimarsson
Helgi
H
Gulcher
Jeffrey R
JR
D000483:Alleles; D015535:Arthritis, Psoriatic / Q000235:genetics*; D002874:Chromosome Mapping; D002885:Chromosomes, Human, Pair 16 / Q000235:genetics*; D005260:Female; D020022:Genetic Predisposition to Disease / Q000235:genetics*; D018392:Genomic Imprinting / Q000235:genetics*; D006801:Humans; D008126:Lod Score; D008297:Male; D018895:Microsatellite Repeats / Q000235:genetics