Utility of the affected sib pair method to detect linkage of a sex-linked dominant disease with a sex-linked recessive trait.

Use of affected sib-pairs for linkage determination of a sex-linked dominant disease with a recessive X-chromosome marker will require extremely large sample sizes, particularly when the marker is marginally polymorphic. In addition, this method should not be used without caution on data collected for a traditional LOD score analysis, without considering the parental mating types involved in the informative families. Nevertheless, ascertainment adjustment and correction for dependence of multiple pairs of affected sib-pairs in families suggests that this method provides linkage inference concordant with that of the traditional LOD score analysis.