ABSTRACT
In 1999 the European Society for Human Reproduction and Embryology reported referrals for pre-implantation genetic diagnosis (PGD) for some 24 genetic disorders; by 2006 one American clinic was offering PGD for over 100 single gene disorders. With the development of PGD couples can seek in vitro fertilisation and have the resulting embryos tested, having only 'normal' embryos returned to the womb. PGD is already offered for familial adenomatous polyposis (FAP), an autosomal dominant disorder where carriers of the gene have a 95 per cent chance of developing precancerous polyps in the colon by 35 years of age. This late onset disease can be controlled by early molecular genetic testing, surveillance and treatment, but carriers of the gene are at high risk of developing cancer of the colon. Predisposition for ovarian cancer is 55 per cent for BRCA1 and 25 per cent for BRCA2.
