The Turkish Van (pronounced Von) is a naturally occurring breed of domestic cat that originated in the mountains of Turkey. The Van is classified as a semi-long hair, but it has two lengths of hair, determined by season. In the winter, the hair is thick and long. In the summer, the hair sheds to leave a short light coat. Both coat lengths are typified as being as soft as cashmere, down to the root. There is no evident undercoat on the Van, only one coat. The breed is rare, and is distinguished by the Van pattern (named after the breed), where the color is restricted to the head and the tail, and the rest of the cat is white; this is due to the expression of the piebald white spotting gene, a type of partial leucism.:148 A Turkish Van may have blue or amber eyes, or be odd-eyed (having one eye of each colour). The breed has been claimed to be descended from the landrace of usually all-white Van cats (Turkish: Van kedisi), mostly found near Lake Van. The Western preference for matching eyes in the Van cat is a source of amusement to the people of the Lake Van region.The term "Turkish Vankedisi" is used by some as a name for all-white specimens of the formal Turkish Van breed, although they are not considered show quality and are therefore actively bred against. They are prone to deafness; this is a common defect with many all-white animals.