An extension of the Maximum Lod Score method to X‐linked loci
CORDELL HJ., KAWAGUCHI Y., TODD JA., FARRALL M.
SUMMARYThe Maximum Lod Score method for affected relative‐pair analysis, introduced by Risch, is a powerful method for detecting linkage between an autosomal marker locus and disease. In order to use the method to detect linkage to markers on the X‐chromosome, some modification is necessary. Here we extend the method to be applicable to X‐chromosomal data, and derive genetic restrictions on the haplotype‐sharing probabilities analogous to the ‘possible triangle’ restrictions described by Holmans for the autosomal case. Size criteria are derived using asymptotic theory and simulation, and the power is calculated for a number of possible underlying models. The method is applied to data from 284 type 1 diabetic families and evidence is found for the presence of one or more diabetogenic loci on the X‐chromosome.