title: Departure from the triangle constraints in discordant sib pairs: a test for genetic heterogeneity.
abstract: For any genetic model, Holmans showed that the proportions of affected sibs sharing 2, 1, or 0 identical-by-descent parental marker alleles are constrained to belong to a specific triangle. The triangle constraints do not hold when the sib phenotypes are determined by different models. We test the rejection of triangle constraints on affected sib pairs discordant for severity, to determine whether different models control the severe and mild forms of the disease in the simulated data. With this method we show that a locus on chromosome 5 plays a different role in the two forms of the disease.
authors.affiliation: INSERM U155, Bois de Boulogne, Paris, France.
authors.forename: H
authors.initials: H
authors.lastname: Quesneville
authors.forename: M H
authors.initials: MH
authors.lastname: Dizier
authors.forename: F
authors.initials: F
authors.lastname: Clerget-Darpoux
mesh_terms: D008040:Genetic Linkage; D005819:Genetic Markers; D020022:Genetic Predisposition to Disease; D005820:Genetic Testing; D006801:Humans; D016013:Likelihood Functions; D008126:Lod Score; D008957:Models, Genetic; D015233:Models, Statistical; D009679:Nuclear Family; D010641:Phenotype; D011110:Polymorphism, Genetic
chemical_list: D005819:Genetic Markers