This happens from time to time. It seems likely that pigmentation (not perjorative!) is a addition to survival. Having it enables survival where sunshine is strong and the individual is outdoors a lot. Having it in a weak sunshine environment or where the individual is is indoors, means rickets and cancer and many other disorders, related to Vitamin D deficiency. Thus the possibly not random loss of additional pigmentation may increase. I am nopt fully convinced by the out of Africa theory, but this occurence supports it. Low pigmentation individuals, (pigment challenged!) may also produce darker pigmentation children. Indians depict Aryans with blue skin, arising from the veins being visible through poorly pimented skin. Blue bloods! It reflects their ability to survive without working in the sun. Octaroons etc is also a term like mulatto. Niger, Negro means "black" Alba means "white". Latin, doncha'know!
Albino is now a medical term meaning no pigment at all. Eyes therefore are red. Low pigment get a choice! Skin will not freckle, but burn at the slightest provocation.