By Sharon Cotliar

05/16/2013 at 07:00 AM EDT

Angelina Jolie says she underwent a double mastectomy after she found out she carried the “faulty” BRCA1 gene and was told she had an 87 percent chance of developing breast cancer.

The announcement not only made headlines around the world, but prompted questions of whether other women need to be concerned if they too carry the mutated gene.

Here are seven things to know:

1. What is BRCA1 and BRCA 2?
They’re genes everyone has. But those who have a bad copy or mutation are at increased risk for developing breast and ovarian cancer.

2. How common is it?
Less than 1 percent of people in the U.S. have one of these mutated genes, but the prevalence is higher among Ashkenazi Jews and among those with a personal or family history of breast or ovarian cancer. Still, only 5 percent of the 220,000 cases of breast cancer diagnosed in the U.S. each year are related to the defective genes.

3. What are the odds of inheriting the mutated gene?
If one parent has the gene mutation, there’s a 50-50 chance of getting a bad copy of the gene. “Both your mother and father’s side matters,” say Dr. Susan Domchek, director of the Basser Research Center at the University of Pennsylvania.

4. What are the odds of developing breast or ovarian cancer if you have one of the mutated genes?
“They’re dramatically higher than the general population,” says Dr. Mehra Golshan, director of breast surgical services at Brigham and Women’s Hospital in Boston.

Between 60 percent to 85 percent develop breast cancer and between 20 percent to 50 percent develop ovarian cancer. “That’s why it’s important to consider genetic testing if you have a family history,” says Dr. Golshan.

5. What can you do about it if you’re a carrier?
More women are choosing to undergo preventive mastectomies, as Jolie did. Women can also opt to be monitored closely for signs of cancer or precancerous red flags, undergoing more frequent mammograms and MRIs.

For those concerned about developing ovarian cancer, there are fewer options. “It’s recommended that BRCA1/2 mutation carriers have their ovaries and fallopian tubes removed by age 40 as screening for ovarian cancer is not effective,” says Dr. Domchek.

Others suggest it be done after child bearing, even though it can trigger early menopause. Jolie, who also revealed she has a 50 percent chance of developing ovarian cancer, has chosen to undergo surgery to remove her ovaries at a later date and will likely undergo a laparoscopic or minimally invasive procedure, which offers a quick recovery.

6. Who should be tested?
If you have a personal or family history of breast cancer under age 50; ovarian cancer at any age; breast cancer in both breasts; male breast cancer; multiple cases of breast cancer within a family; or breast cancer with Ashkenazi Jewish ancestry, genetic counseling is recommended to determine if genetic testing is appropriate. “The best defense is to talk to your doctor and develop a plan of action,” says Dr. Domchek.

7. What does the test involve? And does insurance cover it?It’s a simple blood or saliva test, but it can cost more than $3,000 for the genetic analysis. Insurance typically covers it for those deemed high-risk but some insurance plans, including Medicaid in some states, don’t.