What is Poliosis?
Poliosis is the decrease or absence of melanin (or color) in head hair, eyebrows, or eyelashes. It can give rise to a "Mallen Streak" that can be hereditary. Catherine Cookson wrote a novel and later a TV series called The Mallen Streak, where a family had the condition. Sports presenter Dickie Davies and runner Sam Brown were famous for this feature. People with Waardenburg syndrome usually present this symptom, as do 60% of patients with tuberous sclerosis.