Читать книгу Genetic Analysis of Complex Disease - Группа авторов - Страница 64

There are three basic designs of case ascertainment for a genetic analysis of a binary (present/absent) trait: collection of a single affected individual (case), relative pairs from a family, and extended families with multiple affected and unaffected individuals. Examples of these ascertainment schemes are shown in Figure 3.1. As shown below, certain sampling schemes limit the types of analyses that can be performed. However, one’s sampling scheme is often dictated by the natural history of the condition under investigation. For example, with late‐onset disorders such as Alzheimer disease, Parkinson disease, and chronic obstructive pulmonary disease, collection of the parents of an affected individual is often not feasible as the parents are often already deceased. In such cases, one may be restricted to collection of affected sibpairs, or a case‐control sample.

Figure 3.1 Ascertainment schemes for genetic analysis.