The impact of molecular genetics on oral health paradigms

As a result of our increased understanding of the human genome, and the fun ctional interrelationships of gene products with each other and with the en vironment, it is becoming increasingly evident that: many human diseases ar e influenced by heritable alterations in the structure or function of genes . Significant advances in research methods and newly emerging partnerships between private and public sector interests are creating new possibilities for utilization of genetic information for the diagnosis and treatment of h uman diseases. The availability and application of genetic information to t he understanding of normal and abnormal human growth and development are fu ndamentally changing the way we approach the study of human diseases. As a result, the issues and principles of medical genetics are coming to bear ac ross all disciplines of: health care. In this review, we discuss some of th e potential applications of human molecular genetics for the diagnosis and treatment of oral diseases. This discussion is presented in the context of the ongoing technological advances and conceptual changes that are occurrin g in the field of medical genetics. To realize the promise of this new mole cular genetics, we must be prepared to foresee the possibilities and to inc orporate these newly emergent technologies into the evolving discipline of dentistry. By using examples of human conditions, we illustrate the broad a pplication of this emerging technology to the study of simple as well as co mplex genetic diseases. Throughout this paper, we will use the following te rminology: Penetrance-In a population, defined as the proportion of individ uals posessing a disease-causing genotype who express the disease phenotype . When this proportion is less than 100%, the disease is said to have reduc ed or incomplete penetrance. Polymerase chain reaction (PCR)-A technique fo r amplifying a large number of copies of a specific DNA sequence flanked by two oligonucleotide primers. The DNA is alternately heated and cooled in t he presence of DNA polymerase and free nucleotides, so that the specified D NA segment is denatured, hybridized with primers, and extended by DNA polym erase. MIM-Mendelian Inheritance in Man catalogue number from V. McKusick's Mendelian Inheritance in man (OMIM, 1998).