A person who first draws attention to their family. For example, if my eye doctor discovers i have glaucoma and subsequently other cases of glaucoma are found in my family, i am the index case. Also called the propositus (if male) or proposita (if female). ... (12 Dec 1998) ... 
The index case is the first disease case in an epidemic. Sometimes called 
Type: Term Synonyms: proband
Index case: A person who first draws attention to their family. For example, if my eye doctor discovers I have glaucoma and subsequently other cases of glaucoma are found in my family, I am the index case. Also called the propositus (if male) or proposita (if female).
The patient in an outbreak of a disease who is first identified by health authorities.