Gene expression has been proposed as an intermediate phenotype that can increase power in complex trait gene-mapping studies. Psoriasis, an immune-mediated, inflammatory and hyperproliferative disease of the skin and joints, provides an ideal model system to evaluate this paradigm, as conclusive evidence demonstrates that psoriasis has a genetic basis and the disease tissue is readily accessible. To better understand the complex nature of processes in psoriasis, we characterize gene expression profiles in uninvolved and involved skin from affected individuals as well as normal skin from control individuals.
Keywords: disease state analysis
Overall design
We extracted total RNA from punch biopsies taken from 58 psoriatic patients and 64 normal healthy controls. Two biopsies were taken from each patient; one 6mm punch biopsy was obtained from lesional skin of each patient (involved sample) and the other from non-lesional skin (uninvolved sample), taken at least 10 cm away from any active plaque. One biopsy was obtained from each healty control. Totally 180 samples were run on Affymetrix HU133 Plus 2.0 microarrays containing >54,000 gene probes. The raw data from 180 microarrays were processed using the Robust Multichip Average (RMA) method. The expression values in the table were after adjustment of RMA expression values (on the log scale) to account for batch and sex effects. Definition of abbreviations used in Sample records: NN = normal skin from controls; PN = uninvolved skin from cases; PP = involved skin from cases.