Sickle cell disease is a blood disorder where red blood cells become sickle-shaped, clogging blood vessels and limiting oxygen flow. It is most common among those with ancestry from sub-Saharan Africa, India, and Saudi Arabia. The disease is inherited, with a 25% chance of being affected if both parents carry the recessive gene. Treatment focuses on preventing infections and complications to help manage the condition and improve life expectancy, now into the 40s.