We propose to investigate the genetics of the scaling disorders and other genodermatoses which are believed to behave in a Mendelian manner. Families for study will be ascertained through articles in the Ichthyosis Focus, (the newsletter of the Foundation for Ichthyosis and Related Skin Types), physician referrals, and patient self-referrals. Efforts will be made to further characterize the clinical findings in both affected persons and unaffected gene carriers. Using candidate genes, especially those known to be involved in structural abnormalities of skin, we will attempt to map and isolate major genes contributing to expression of the disease phenotype. Failing this direct approach, a random search of the genome (so-called, "reverse genetics") will be utilized. In addition, normal and diseased skin will be used in cell culture and animal experiments (under a separate protocol) to test new therapeutic modalities.