The Butan tribe is in a remote part of Sulawesi in Indonesia. This is because of a rare genetic disorder called Waardenburg syndrome which causes congenital hearing loss and pigmentation deficiencies, which can include bright blue eyes. Your eye color results from the amount of melanin your body makes. Melanin is a pigment that gives color to your eyes, hair and skin. The colored part of your eye is called the iris. As many as 16 genes influence eye color by determining the amount of melanin inside the specialized cells of the iris. Different eye colors are caused by different amounts of pigment.
Maybe this is not such a fun fact for people affected, however I certainly learnt something this morning.
The members of the Butan tribe have a rare genetic defect that gives them electric blue eyes