Smith-Lemli-Opitz Syndrome (SLOS) Montana State University Shodair Hospital Pathology Medal of Honor of the DGofH (German Society of Hum Genet) John M. Opitz (August 15, 1935 – August 31, 2023) was a German-American medical geneticist and professor at the University of Utah School of Medicine.

[1] It was at the age of 15 that his uncle introduced him to Emil Witschi, an internationally acclaimed embryologist, endocrinologist, and zoologist at the University of Iowa, who fanned Opitz' interest in embryology, genetics and evolution.

After completing high school, Opitz studied Zoology at the University of Iowa under Witschi's tutelage, receiving his bachelor's degree in 1956.

[3] While attending medical school, Opitz was engaged in a variety of other research projects including: glucose metabolism (with N. Halmi),[4] prostate cancer (R. Flocks),[5] and hereditary hematuria (W.W.

Smith introduced him to the University of Wisconsin Children's Hospital where he began his work on the physical and biological manifestations of syndromes.

He also gained experience in the evaluation of normal developmental variability by examining the newborn infants at St. Mary's Hospital in Madison for Smith's study of minor anomalies.

[7] In 1979, at the invitation of Philip D. Pallister, Opitz left the University of Wisconsin to become the Director of the Shodair-Montana Regional Genetic Service Program in Helena, Montana.

Later he served as chair of the Department of Medical Genetics at Shodair Children's Hospital and as an adjunct professor in Biology, History and Philosophy, Medicine, and Veterinary Science at Montana State University.

This collaboration also led to the discovery of the first human X-autosome translocation which, according to McKusick, was a jumping off point for the era of chromosome mapping.