There comes a time in the life of every vitiligo patient when we ask ourselves: „Will my children develop vitiligo ?”
The frequency of vitiligo among siblings is 6.1% which is about 18 times higher then the usual population frequency, suggesting a major genetic component in the disease. The probability that a pair of twins will both have vitiligo is 23% indicating that a non-genetic component also plays a role. 

According to a study published in the Pigment Cell Research magazine, vitiligo occurs with a frequency of 0.1 to 2.0% in various populations. The study surveyed a number of 2642 subjects from North America and UK regarding the disease characteristics and familial background. More then 83% of subjects were Caucasian with equal distribution of the disease in both males and females.

Subjects with an earlier disease onset were more prone to have relatives with vitiligo. Also, vitiligo patients and their first degree relatives were found to have an elevated frequency of some other autoimmune diseases: vitiligo itself, autoimmune thyroid disease (particularly hypothyroidism), pernicious anemia, Addison's disease, systemic lupus erythematosus. This associations reveal that vitiligo shares the same genetic background as these other autoimmune disorders.

Source:
Pigment Cell Research. 16(3):208-214, June 2003.
Alkhateeb, Asem 1; Fain, Pamela R. 1,2,3; Thody, Anthony 4; Bennett, Dorothy C. 5; Spritz, Richard A. 1,2