Invited commentary: The need for human genetics and genomics in dental school curricula.

There are currently 67 dental schools in the United States and Puerto Rico. According to the 2014 edition of the Official Guide to Dental Schools For Students Entering in Fall 2015 published by the American Dental Education Association (www.adea.org), no dental schools currently require genetics prior to admission. Only one school, the University of Florida, requires one semester of molecular biology or genetics for admission. When last surveyed in 2001, only eight of 53 dental schools had a formal course in human genetics in their curricula (Dudlicek et al. 2004). Only one school did not respond to the survey. Despite calls from a variety of individuals and professional organizations that genetics should be an integral part of dental school curricula (Wright and Hart 2002; Behnke and Hassell 2004; Collins and Tabak 2004; Johnson et al. 2008; Slavkin 2014), little progress has been made to improve the teaching of human genetics to dental students. With this in mind, we once again call for dental schools to include human genetics as a formal course in their curricula. A search of the scientific literature reveals how the contribution of genetic factors to missing or misshapen teeth, cleft lip/palate, oral cancer, caries, periodontal disease and other oral pathologies and conditions continues to expand. The effects that systemic disorders can have on an individual’s oral health are also well known. Gingival hyperplasia can be an isolated condition, part of a syndrome, or a side effect of certain medications. If a side effect of medication, it is reversible simply by stopping the drug. Inherited forms require surgical resection. Thus, a dentist needs to able to take a family and medical history to distinguish the forms. Associations have been made between enamel defects and kidney disease (Jaureguiberry et al. 2013), between missing teeth and colon cancer (Lammi et al. 2004), and between microdontia and deafness (Riazuddin et al. 2011). Knowing whether a dental phenotype is an isolated finding or is associated with other systemic manifestations with broader healthcare implications can lead to appropriate referrals. Dentists clearly have patients with genetic disorders in their practice. These genetic disorders may or may not have an impact on their oral health. These include Mendelian traits such as amelogenesis imperfecta and cystic fibrosis, cytogenetic disorders such as Smith–Magenis and Williams syndromes, as well as multifactorial traits such as cleft lip/cleft palate or diabetes. The last decade has seen an explosion in the number of genes associated with craniofacial development and diseases. Currently, mutations in at least seven genes are associated with amelogenesis imperfecta, a disorder of qualitative or quantitative defects of enamel (Table 1). There are several reasons why genetics and genomics should be included in dental school criteria beyond the obvious value of making a dental diagnosis. Being able to take a family history to construct a three-generation pedigree is crucial. While one should not discount the psychological or financial burden of missing or malformed teeth, genetic disorders may also have extraoral health consequences. For example, dentinogenesis imperfecta (DI) may occur as an isolated finding or as part of a syndrome such as osteogenesis imperfecta (OI), which is associated with bone fragility and hearing loss (Hart and Hart 2007). Mild type 1 OI may be mistaken for isolated DI (Pallos et al. 2001). Making a correct diagnosis is crucial for a discussion of phenotypic consequences, management, and genetic counseling for recurrence risks. Enamel