Introduction to genetics

© 2019 American Society for Bone and Mineral Research. Genetic mutations causing Mendelian diseases usually have a large effect, whereas oligogenic or polygenic disorders summate smaller effects, sometimes with contributions from the environment. This chapter briefly reviews mineral metabolism and skeletal diseases with a genetic element underpinning their identification and characterization based on clinical evaluation. It includes a detailed medical history and physical examination, and their mode of inheritance based on appropriate interpretation using genetic testing. Many mineral metabolic and skeletal disorders have a monogenic etiology. Several factors must be considered before requesting genetic testing. These include the phenotype of the patient, the likely mode of inheritance, the potential genetic etiology and availability of additional pedigree members if necessary to aid diagnosis. Single nucleotide polymorphism arrays detect copy number variations as well as genome-wide genotyping. Prenatal genetic testing is used once pregnancy is established to identify fetuses at risk of genetic disease.