Prenatal diagnosis of single-gene disorders: case studies

In volume 13 issue 3 of this journal, various methods for diagnosing single-gene disorders in the antenatal period were reviewed. The general principles remain the same and have not been discussed again in detail here. Instead, four cases are described that illustrate the points made in this original article, with reference to background information where necessary. Molecular biology is playing an increasingly important role in the prenatal diagnosis of single-gene disorders. In the absence of a family history, or a previously affected sibling, it is usually ultrasound, however, that first raises the possibility of one of these diagnoses in the prenatal period. Clinical investigations, histopathology and molecular testing following birth, or termination of pregnancy, usually combine to provide a precise diagnosis, after which molecular testing in a future pregnancy often becomes possible if the recurrence risks are high.