Abstract
Medical geneticists and genetic counselors regularly see families attending the genetic counseling clinic with questions about chromosome abnormalities. These families may themselves have had a child affected with a chromosome condition; or, there may have been a history elsewhere in the family. The presentation may have been due to infertility or reproductive loss. Questions may include the following: What is known about this condition? What caused this to happen? Is it likely to happen again? If so, is there a way to prevent it from happening again? The power of molecular approaches to chromosome analysis, coming to be routinely available in this second decade of the twenty-first century, has brought to our knowledge many new “chromosomal syndromes” to add alongside those long known from the days of classical cytogenetics. This new knowledge has increased our ability to answer the questions that families may have; but equally, it has raised challenges in interpretation, as molecular karyotyping has revealed more complexity in the way the human genome is constructed. This book distils the knowledge that has evolved in recent and olden times, and it presents the information in a way that will be helpful to the practitioner. In particular, the risks of recurrence, or of occurrence, of a particular chromosome disorder are clearly set forth. The application of chromosomal knowledge to reproductive conditions, both diagnostically and in management, is rehearsed.