Mutations in the EDA gene cause anhidrotic ectodermal dysplasia (EDA), with lesions in skin appendage formation. To begin to analyze EDA pathways, we have used expression profiling on 15,000-gene mouse cDNA microarrays, comparing adult mouse skin from wild-type, EDA-defective (Tabby) mice, and Tabby mice supplemented with the EDA-A1 isoform, which is sufficient to rescue multiple Tabby phenotypes. Given the sensitivity of the current microarray system, 8500 genes (60%) were estimated to be expressed, including transcription factors and growth-regulatory genes that had not previously been identified in skin; but only 24 (0.16%), one-third of them novel, showed significant differences between wild type and Tabby. An additional eight genes not included in the 15,000 gene set were shown to have expression differences by real-time RT-PCR. Sixteen of 32 affected genes were restored significantly toward wild-type levels in EDA-A1 transgenic Tabby mice. Significant up-regulation in Tabby skin was observed for several dermal matrix genes, including Col1a1, Col1a2, Col3a1 and SPARC: In contrast, down-regulation occurred for the NEMO/NF-kappa B pathway, already implicated in skin appendage formation, and even more markedly for a second pathway, JNK/c-jun/c-fos and their target genes, that has not previously been clearly associated with skin development. These data are consistent with the regulation of the NF-kappa B pathway by EDA, and support its involvement in the regulation of the JNK pathway as well.