A curious genetic coincidence found in a study of palmoplantar keratoderma

In a study of hereditary palmoplantar keratoderma of the Unna Thost variety in the northernmost county of Sweden (Norrbotten) a genetic coincident between this inherited disorder and the autosomal dominant form of ichthyosis vulgaris was found. In the same family a patient with ichthyosis vulgaris combined with palmoplantar hyperkeratosis and hyperkeratotic plaques on the knees and the elbows appeared.