One of the books I’ve read recently, mentioned that if your family has a history of autoimmune diseases of one sort or another, that there is an increased likelihood that you might be susceptible to an autoimmune problem. There is no “close” connection between thyroid and vitiligo in the sense of cause and effect, necessarily. It’s just that the presence of one or more autoimmune problems in a family indicate that there is a genetic predisposition for them. And even given the predisposition, there’s no way of telling if anybody will get one or not.
My best friend has vitiligo (and no thyroid problems). Her condition has been kept under control for the most part in recent years.
Take care,
Bobbi