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 will focus 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, more recently techniques have been developed to diagnose genetic disorders by testing maternal blood for the presence of foetal DNA. The current and future uses of this non-invasive prenatal diagnosis will be discussed.