ABSTRACT
This chapter explores the range and limitations of tests of carrier status and attempts to show how the information can be used in conjunction with other genetic and clinical data to make as accurate a determination as possible. When the testing of carriers is being considered, it is often not recognised that, in addition to individuals at a higher or lower risk of being a carrier, there are those who, on genetic grounds, must be carriers. Rare autosomal recessive disorders are the ones about which advice is most commonly sought, and family members may be greatly worried and alarmed by having been told they may be carriers. The common autosomal recessive disorders provide a much more important indication for carrier detection, although the disorders have to be extremely common to present a significant risk to individual couples. A relatively small number of X-linked recessive disorders provide the most important of all applications of carrier detection.
