Two to six percent of all newborn children have a disorder with a genetic cause (1-3).
For an increasing number of these diseases, the precise genetic cause is known and
this can lead to new treatment opportunities (see Appendix A for a basic description
of the mechanisms of genetic inheritance). However, for most disorders total cure is
not yet possible. For example, complications in patients with cystic fibrosis can be
reduced by intensive treatment, but many patients will still die of lung problems
caused by the disease. For diseases for which cure is not yet possible genetic
screening might be a (temporary) solution. For example, a genetic screening
programme in most Western countries is the offer of amniocentesis to pregnant
women of a specified age (36 years and older in The Netherlands) to detect Down
syndrome. Women in whom a foetus with Down syndrome is detected can then
decide to prepare for the birth of an affected child or to avoid its birth by induced
abortion. A list with examples of tests to detect disorders with a genetic cause or
component currently offered in The Netherlands is given in Table 1.1. Because of the
increasing number of genetic diseases that can be detected early, this list will
probably continue to be extended
