Public awareness raised by Jolie dilemma

Genetic testing first attracted the attention of the Chinese public when Angelina Jolie opted for radical surgery after tests indicated she was genetically disposed to certain cancers. The news prompted widespread debate and also provided publicity for the country’s genetic-testing industry.

In 2015, tests indicated that the US actress and campaigner had a defective BRCA1 gene. When healthy, the gene acts as a tumor suppressor, but faulty genes are thought to actively promote the growth of cancer cells.

Jolie announced that she had undergone a double mastectomy and had both ovaries removed because the presence of the faulty gene suggested she had an 80 percent chance of contracting breast cancer and a 40 percent chance of ovarian cancer.

Genetic testing allows the detection of changes in chromosomes, genes or proteins. The results can help to confirm or contradict suspected genetic anomalies and assess a person’s chances of developing, or passing on, certain genetic disorders. About 1,000 different tests are available in hospitals and nonclinical facilities.

As scientists have delved deeper into the mysteries of DNA, more tests have been developed.

In China, demand for personal tests rose dramatically in the wake of Jolie’s announcement, with the most popular focusing on the potential risk of developing illnesses such as cancer and diabetes. Away from the field of medicine, the most popular commercial tests are those used to trace genetic ancestry or assess an individual’s reaction to excessive consumption of alcohol.

Molecular testing studies individual genes or short strings of DNA to identify variations or mutations that may result in serious illnesses, while chromosomal tests assess entire chromosomes or long strings of DNA in search of major genetic changes, such as extra chromosomes, which could cause genetic conditions. Biochemical tests focus on the number of proteins and their levels of activity, because abnormalities in either can indicate changes to DNA that may result in genetic disorders.