Mice homozygous for a targeted mutation in Dsg1b are described to exhibit increased bone mineral content as well as abnormal eye morphology, whereas humans with various heterozygous mutations in the human ortholog DSG1 are described to show palmoplantar keratoderma I (OMIM: 148700) and erythroderma with palmoplantar keratoderma, hypotrichosis, and hyper-IgE (OMIM: 615508) (http://www.informatics. This evidence concerns the gene DSG1 and Palmoplantar keratoderma.