When to Refer to the Geneticist

Abstract

WITH THE recent dramatic advances in medical genetics and the increased interest in genetic counseling, most physicians have lost sight of the fact that they have been involved with genetic evaluations in the private practice of medicine for many years. Essentially, all human beings have normal physical characteristics that have been developed as the result of the interaction between small contributions by multiple genes and the environment. These multiplegene or polygenic multifactorial inheritance patterns have always been noted by lay persons as well as physicians. Both groups expect short parents to produce short children and large parents to produce large children. We expect obese individuals to have family histories of obesity. Characteristics such as height, weight, head circumference, lean body mass, intelligence, and age of sexual maturation represent this polygenic endowment interacting with one's environment. The standards that we physicians use for normalcy are derived from studies of groups of