Huntington disease: estimation of heterozygote status using linked genetic markers

The recent finding of a closely linked DNA marker to the Huntington Disease gene allows the opportunity for prenatal and preclinical diagnosis. The methodology for using these markers for prediction in late age of onset disorders is discussed. Since these methods are both difficult and complex for the majority of genetic counselors, a simple solution is suggested. This involves using the well known linkage program LIPED and running it twice for a given consultand, once assuming he carries the gene and once that he is homozygous normal. This will allow accurate predictions for counselors with limited backgrounds in pedigree analysis.