Genetics beyond Mendel - Understanding nontraditional inheritance patterns

As the Human Genome Project unfolds, more and more genetic disorders are be ing found that are not transmitted in the usual dominant, recessive, or X-l inked pattern. How do you explain these strange exceptions to Mendelian rul es to your patients and their families? In this article, Dr Wagstaff discus ses imprinting, trinucleotide repeat expansion, mitochondrial inheritance, and mosaicism and explains how they occur and how they affect transmission of inherited diseases.