The Genetics Counselor

The Genetics Counselor is a computer program, written in LISP, designed to handle problems of medical genetics counseling. It is an attempt to apply the methods of artificial intelligence research to medical diagnostic problems. The program attempts to map the data space of a family-tree structure into the hypothesis space of classical Mendelian genetics by use of a heuristic search. The input data are the family members along with their children (or parents), and phenotype. The program generates a family tree and searches for consanguinity. The hypothesis space consists of the Mendelian modes of inheritance. Heuristic conditions are used to search the data space to eliminate untenable hypotheses. If more than one type of inheritance is possible, the program generates the probable genotypes of each member of the family based on the possible hypotheses. It then tests the expected phenotypic expression based on a particular inheritance against observed distribution of the phenotype. After investigating all the hypotheses not expressly invalidated, the program selects the most plausible hypotheses explaining the data, and orders the remaining ones. The likelihood of a parent having an affected offspring is estimated based upon the plausible hypotheses.