A piebald person can be perfectly normal whereas Waardenburg syndrome is a group of genetic conditions that can cause hearing loss and hypopigmentation of the hair, skin, and eyes.

Pietrus sp? Waardenburg discovered Waardenburg syndrome in the Netherlands. It was the early 50s. I think it was 1951. He was a Dutch ophthmologist (eye doctor MD) who discovered many school children with different colored eyes (heterochromatica ) were deaf. WS is a leading cause of deafness.

Autosomal dominant allele

Waardenburg syndrome affects people of all ethnicities equally. However, certain features of the syndrome may be more noticeable in individuals with lighter skin and hair due to the contrast in pigmentation.

Glaucoma, Waardenburg syndrome, Neurofibromatosis, or some mild infection infecting one eye.