Half Italian, half-Scottish forensic expert Enzo Macleod has distinctive good looks: long hair with a streak of white pulled back in a ponytail, and eyes of different colors. This is because Macleod has a genetic syndrome, called Waardenburg Syndrome, affecting hair color, eye pigmentation and sometimes hearing. It's so named for the Dutch eye doctor, Petrus Johannes Waardenburg, who first noticed that people with differently colored eyes often had a hearing impairment, and defined the syndrome in 1951.
Overall, the syndrome affects an estimated 1 in 42,000 people; about 1 in 30 students in schools for the deaf have Waardenburg syndrome. The condition is usually inherited from one parent with the altered gene that carries it, though in rare cases it can be caused by a new mutation to the gene. It is also very rarely associated with slightly diminished cognitive function, cleft lip, intestinal and spinal defects, and other congenital disorders.