title: Ascertainment models for human families selected through several affected children.
abstract: Sampling models for families having normal and affected children and being selected through information about two or more of the affected ones have been developed. Such a model, a so-called ascertainment model, yields the conditional probability that a family has r affected children given that it has s children altogether and that it has been selected or ascertained with a probability which is proportional to a given power of the number of different groups of m less than or equal to r affected children. When the power equals zero or one the model is simplified considerably. If also m = 1 we get the well-known complete ascertainment and single ascertainment model as special cases.
mesh_terms: D002648:Child; D030342:Genetic Diseases, Inborn / Q000235:genetics*; D006801:Humans; D008954:Models, Biological; D010375:Pedigree; D011336:Probability