Psoriasis vulgaris and psoriatic arthritis share a 100 kb susceptibility region telomeric to HLA-C.
OBJECTIVE
To map the locus for susceptibility to psoriasis in patients with psoriatic arthritis.


METHODS
Seventy-four patients with psoriatic arthritis and 95 patients with psoriasis vulgaris were included in this study. Polymorphic genes and microsatellite markers centromeric (C1_2_5) and telomeric (C1_4_4, OTF3, HCR and the corneodesmosin gene) to HLA-C were studied in an association analysis. Typing was also performed on a control population of 104 matched donors.


RESULTS
The allele Cw*0602 was associated both with psoriasis [49 vs 21%, Pc<0.0003; odds ratio (OR)=3.6, aetiological factor (AF)=0.72] and with psoriatic arthritis (62 vs 21%, Pc<0.000001; OR=6.1, AF=0.83). In psoriatic patients a susceptibility region telomeric to HLA-C that includes C1_4_4 (56 vs 22%, Pc<0.0002; OR=4.39, AF=0.77), OTF3 (85 vs 60%, Pc<0.0002; OR=3.7, AF=0.73) and HCR (63 vs 26%, Pc<0.00001; OR=3.8, AF=0.74) was observed. In psoriatic arthritis patients the susceptibility region was delimited by HLA-C and C1_4_4 (384 allele, 56 vs 22%, Pc<0.0002; OR=4.37, AF=0.77).


CONCLUSIONS
Comparing the susceptibility regions associated with the two diseases, an overlapping interval of 100 kb between HLA-C and OTF3, which might contain the psoriasis gene, can be defined.
Department of Immunology, Hospital Central de Asturias, Oviedo, Spain.
J
J
Martínez-Borra
S
S
González
J
J
Santos-Juanes
J
J
Sánchez del Rio
J C
JC
Torre-Alonso
A
A
López-Vazquez
M A
MA
Blanco-Geláz
C
C
López-Larrea
D000328:Adult; D015535:Arthritis, Psoriatic / Q000235:genetics; D002874:Chromosome Mapping; D020022:Genetic Predisposition to Disease; D005838:Genotype; D015236:HLA-C Antigens / Q000235:genetics*; D006801:Humans; D018895:Microsatellite Repeats / Q000235:genetics; D008875:Middle Aged; D011110:Polymorphism, Genetic / Q000235:genetics; D011565:Psoriasis / Q000235:genetics*; D016615:Telomere / Q000235:genetics
D015236:HLA-C Antigens