Although albinism is rare, many animals (including humans) are at risk of it. Being albino refers to a complete absence, or in some cases a reduction in the levels, of melanin that cause pigmentation of the skin, eyes and hair. This is due to a fault in the function of the enzyme that produces melanin. It is a genetic condition, caused by inheritance of two recessive genes, though this is a very rare occurrence. As well as lightening the colour of skin and hair, albinism can also affect the way the visual system develops and lead to sight problems.