Young Red Haired Girl Portrait

Red hair of pathological origin
Most red hair is caused by the MC1R gene and is non-pathological. However, in rare cases red hair can be associated with disease or genetic disorder:
• In cases of severe malnutrition, normally dark human hair may turn red or blonde. The condition, part of a syndrome known as kwashiorkor, is a sign of critical starvation caused chiefly by protein deficiency, and is common during periods of famine.