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).

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index case n

1) an instance of a disease or a genetically determined condition that is discovered first and leads to the discovery of others in a family or population

2) index patient <we first examined the index case when he was aged 59 years (Stephanie B. Matthews & Anthony Campbell)>

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1. the first case observed in a family or other defined group, which provides the stimulus for a genetic study; the affected individual is called the propositus. 2. in epidemiology of contagious disease, the first case of a disease, as opposed to subsequent cases.