1986 Volume 17 Issue 1 Pages 71-80
Estimation of genetic risk is of importance in genetic counseling. Recently, remarkable advances have been made in the methods of prenatal diagnosis and detection of carriers, but when these cannot be employed, estimation of genetic risk must be made on the basis of the Mendelian segregation ratio. The authors, therefore, devised equations for estimating genetic risk which simultaneously take into account such genetic parameters as mutation rate, gene frequency, penetrance and prenatal selection coefficient under the assumption of simple autosomal dominant and recessive inheritance. We studied the influence of these parameters, in particular the latter two genetic parameters, on the estimation of genetic risk and the following results were obtained. The influence of penetrance is very large in autosomal dominant inheritance and in many cases low penetrance increases the genetic risk with increase of healthy carriers. The influence of penetrance in autosomal recessive inheritance is smaller than in dominant inheritance and in many cases low penetrance decreases the genetic risk. When prenatal selection exists, the genetic risk slightly decreases in both dominant and recessive inheritance.
