For instance, for hystrix ichthyoses, it has been postulated that mutations in KRT1 result in a phenotype with the presence of palmoplantar keratoderma, the IH-CM type, while mutations in KRT10 cause the Lambert type (IH-L), in which palmoplantar keratoderma is absent [25, 26]. This evidence concerns the gene KRT1 and hereditary palmoplantar keratoderma.