Previous studies have provided evidence suggesting common genetic factors for psoriasis and Crohn's disease. The latter has also been associated with variants in genes coding for the interleukin 23 (IL-23) receptor and its ligand IL-12B. German researchers recently conducted a study that analyzed four variants of the IL12B and IL23R genes in patients with psoriasis vulgaris (n=1,114), psoriatic arthritis (n=748) and healthy controls (n=937) to determine the association between these genetic variants and the risk of psoriatic skin and joint disease. Both psoriasis vulgaris and psoriatic arthritis were most strongly associated with the two single-nucleotide polymorphisms (SNPs) and the corresponding haplotype of the IL12B gene, while a weaker association was found with ...