Answer : 4. "A rare heart disease"
Explanation :

Two girls suffering from Kawasaki disease were successfully treated at Coimbatore Medical College and Hospital (CMCH). Kawasaki disease, a rare heart disease, mainly affects children under 5 years of age, causing high fever and swelling of the blood vessels. It is a significant cause of heart disease in children, targeting the coronary arteries. Symptoms include fever, rash, swollen hands and feet, and swollen mucous membranes.