Unlike other pediatric specialties, which usually started as offspring of internal medicine subspecialty development, medical genetics emerged from a basic science only one-half century ago. Scientists and physicians housed in a variety of basic science and clinical departments accomplished many of the major advances in the study of genetic diseases in children. In this article, we trace the development of medical genetics as a scientific and clinical discipline and concentrate on contributions of pediatricians or from departments of pediatrics.

Genetics had its roots in the 19th century when, in 1865, Gregor Mendel, a monk and then abbot in an Augustinian monastery, discovered the laws of inheritance in garden peas, a feat that was overlooked until “Mendelism” was rediscovered in 1900 (1). Walther Flemming first visualized human chromosomes in tumour cells in 1882, and Waldeyer introduced the term “chromosome” in 1888 (2). During the 1880s, Roux, deVries, and Weismann developed the theory that chromosomes carry determinants of heredity and development, and in 1903, Walter Sutton and Theodor Boveri proposed the chromosomal theory of Mendelism. In this same decade, the concept of “inborn errors of metabolism” was introduced by Archibald Garrod, which he formally proposed in his Croonian lectures, published in 1909, discussing alkaptonuria, pentosuria, cystinuria, and albinism (3).

During the next half century, genetics developed as a basic science, with a focus on Drosophila, the mouse, and corn as experimental systems; most human studies were based on biostatistics and population-based mathematical analyses. However, during this time, Mendelian inheritance was defined in a number of disorders, such as albinism, brachydactyly, and symphalangism (4,5). During this era, the concept of “eugenics” evolved, resulting in a societal attempt to improve the gene pool and prevent dissemination of bad genes into future generations. This led to a variety of eugenic practices throughout the world, where individuals with mental deficiency as well as those with physical malformations were prohibited from reproducing, with programs of forced sterilization, etc. The eugenics movement culminated in the “justification” of the Nazi holocaust, but after the Second World War, eugenics and its base in human genetics fell into disrepute.

A scientific approach to human genetics emerged in 1948 with the establishment of the American Society of Human Genetics (ASHG), but it must be stated that the majority of its founding board of directors were members of the American Eugenics Society. Few medical doctors were involved in human genetics at that time, the majority being PhDs with backgrounds in formal (population or statistical genetics), Drosophila, or mouse genetics. Many of these PhD geneticists began studying the inheritance of single gene disorders in human, and some became excellent clinicians in the description of syndromes and birth defects. These included such individuals as Curt Stern in Berkeley, Norma Ford Walker in Toronto, and F. Clarke Fraser in Montreal (who gained an MD after his earlier PhD but never took an internship). Annual meetings of the ASHG began in 1948, and the first International Congress of Human Genetics was held in Copenhagen in 1956, with regular congresses occurring every 5 y since then.

A History of Medical Genetics in Pediatrics