Genetic screening identifies the presence of inherited gene variants which are known to cause or increase the risk of specific diseases. If early detection of genetic mutations can be followed by subsequent risk factor modification or preventive treatment there should be a decrease in mortality risk in those individuals for that cause.
An example of this could be prescribing women with inherited BRCA2 mutations (indicating greater pre-disposition to breast cancer) preventive tamoxifen or performing a preventative mastectomy.
Genetic testing is only useful to the extent that it is known that a specific genetic mutation causes a condition AND such positive identification can lead to preventative measures. Examples that satisfy this are included in the following table.
Sources for the table are listed at the bottom of this page
Note that despite recent improvements, breast cancer still accounts for around 7.5% of all cancer deaths in England and Wales.
Additionally, there is thought to be a role for genomic sequencing in the treatment of cancer. By sequencing the genetic code of individuals’ cancers and noting that cancers with a different genetic makeup can be better treated by certain drugs, a more effective “bespoke” treatment regime could be prescribed. This emerging field is known as pharmacogenomics.
The cost of genetic tests and genome sequencing, as well as our understanding of the interaction between the genome and disease are vital limiting factors for these catalysts.
As such, the specific trigger in question here is that of the cost of genetic screening (where positive identification is acknowledged as potentially beneficial / preventative) falling to a sufficient extent to make this widely affordable or even available at no cost through the NHS.
It is also worth briefly noting that genetic screening brings with it a number of ethical and moral issues which we do not discuss here.
1) Cancer Research UK
2) Bob Carlson. Familial Hypercholesterolemia Captures Gene Test Controversies. Biotechnol Health c. 2010 Spring; 7(1): 8–9.
3) MacLeod, Erin L.; Ney, Denise M. (1 January 2010). "Nutritional Management of Phenylketonuria". Annales Nestlé (English ed.) 68 (2): 58–69.
BRCA 1 and BRCA 2 genes
45-90% life time chance of breast cancer. Also an increased risk of ovarian, pancreatic and prostate cancer.
Preventative Tamoxifen, preventative mastectomy.
LDL receptor gene
The cause of familial hypercholesterolemia. Half of males with FH are expected to have a heart attack before age 45.
Prescribing statins, dietary modification and increased physical activity.
Phenylketonuria resulting from an inability to break down the amino acid phenylalanine. This can lead to seizures and mental retardation.
A strict dietary regimen restricting phenylalanine intake.