The FOLD mutation induces the folded ear phenotype characteristic of the Scottish Fold breed. Cats with this mutation may also have cartilage and bone related health problems, including deformed limbs, thickened and stiffened tails and progressive osteoarthritis. The age of onset and progression of these side effects is highly variable. Cats with two copies of the FOLD mutation are more prone to these health problems than heterozygotes (carriers of only one copy).
