Prenatal diagnosis of single gene disorders

Genetic disease can be due to imbalance of whole chromosomes, smaller microdeletions/duplications or at the single gene level where even a single base change can cause significant disease. This review focuses on those disorders caused by single gene defects and their diagnosis during pregnancy. In many cases the genomic location of a specific gene is known and the disease-causing mutation in a particular family may have been identified. In others, diagnosis may rely on other methodologies such as ultrasound or biochemical testing. Until recently this testing has relied upon invasive testing of a pregnancy. However non-invasive prenatal diagnosis to detect fetal DNA in maternal blood has now been introduced and its current and future utility is discussed.