Concerns that firms' rights to hold patents on genes linked to breast cancer is pushing up cost of testing for disease

Angelina Jolie's decision to speak out about her decision to have a preventive double mastectomy was intended to highlight the terrible risks of breast cancer. But the film star's move also cast a spotlight on the far less known arena of patent battles over genetic technology which could have far more impact than Jolie's widely applauded move.

Before the end of next month the US supreme court will issue a landmark decision in a case brought against the biotech firm Myriad Genetics, which is based in Utah, by the Association for Molecular Pathology.

The firm owns a patent on the BRCA1 gene, which Jolie carries and which is believed to carry a high risk of causing breast cancer. It also owns a patent on the similar BRCA2 gene.

It means that Myriad has the exclusive right to develop diagnostic tests for those genes – a fact that has implications for other firms, who thus might be prevented from developing innovations in the field.

It also has some serious hard-money business implications: in the wake of Jolie's announcement, Myriad's share price shot up. That has worried some commentators. In a New York Times column describing her decision, Jolie acknowledged she was lucky to be well-off enough to easily afford to take the test for the culpable genes.

Some have complained that the lengthy court battle over Myriad's patents has kept the price of the tests too high and have asked whether patents actually sacrifice patients' interests in favour of protecting corporate profits. "How many more women – and men – might have been able over the past four years to afford BRCA1 or BRCA2 testing in the absence of those protective patents?" wrote Andrew Cohen in Atlantic magazine.

The issue of patents and genetic technology is one of growing importance as a flood of companies enter the booming sector and scientific advances allow more and more advanced genetic manipulation. So far the supreme court has shown a willingness to side with big business. Earlier this month it ruled in favour of agricultural firm Monsanto in defence of a patent it holds on soy beans that dominate the US farming sector.