It is considered to be autosomal (not linked to sex) and polygenic. Polygenic means that unlike other genetic diseases involving single genes, Vitiligo and other autoimmune diseases appear to involve many susceptibility genes. Some of these genes might be importantly related to the function of the immune system. At least in some Vitiligo patients the immune system attacks and destroy melanocytes, the pigment-producing cells of the skin. In some families it is associated to other autoimmune diseases, like thyroid disease and pernicious anaemia. One family member may have a thyroid problem and another may have Vitiligo. Vitiligo appears to be not only polygenic (a genetic defect would make melanocytes susceptible to injury) but also multifactorial. These means that there are other factors that probably work in combination and cause the disease. These factors may include the body’s immune system that may destroy melanocytes; abnormally functioning nerve cells that may produce toxic substances that injure melanocytes; production of toxic byproducts that could injure and destroy melanocytes while pigment is forming; and environmental factors, such as infections or damage to the skin. Vitiligo itself is not inherited, but the disposition to have it can be inherited. It is probably a combination of genes that may be the critical factor plus some stimulus capable of starting it off. In the future, a deeper knowledge of which genes are involved may allow genetic testing for individuals that might be predisposed to having Vitiligo. In those individuals environmental risk factors could be more carefully avoided in order to prevent the onset of Vitiligo depigmentation.