Basic Principles of Human Genetics: A Primer for Oral Medicine

Humans have known for several 1000 years that heredity affects health. However, it was only 150 years ago when Gregor Mendel first described the mechanism by which genotype results in phenotype. It was less than 100 years ago when Garrod began to apply genetic knowledge to human diseases and disorders. Ironically, for most of the 20th century, clinicians viewed genetics as a somewhat esoteric academic specialty until rather recently with the completion of the Human Genome Project (HGP) in October 2004.1–3 Meanwhile, rapid advances in high throughput gene sequencing and related bioinformatics have realized that the human genome can be achieved for $1000 per person thereby introducing a tool for diagnostics and prognosis that emphasizes individualized or personalized health care.4–6 Despite enormous public interest in genomics and the thousands of articles published about the completion of the human genome, neither medicine nor dentistry would abruptly change or transform. Medicine and dentistry have not been gene free for the last 100 years. Increasingly, a growing and evolving body of knowledge and information has significantly expanded how we think about and how we use human genetics in medicine and dentistry to address epidemiology, public health and risk assessment, single and multiple predictive and prognostic gene-based diagnostics, and pharmacogenomics and pharmacogenetics with customized drug selection specific for individualized metabolism. We are experiencing an expanding knowledge base for Mendelian inheritance, complex Chapter 25