When Genae Girard received a diagnosis of breast cancer in 2006, she knew she would be facing medical challenges and high expenses. But she did not expect to run into patent problems.

Myriad sells a test costing more than $3, 000 that looks for mutations in the two genes to determine if a woman is at a high risk of getting breast cancer and ovarian cancer.

In contrast, there is solid evidence of serious and common harms, and the screening programme is very costly.