ON THIS PAGE: You will find out more about the factors that increase the chance of developing this type of tumor. To see other pages, use the menu on the side of your screen.
A risk factor is anything that increases a person’s chance of developing a tumor. Although risk factors often influence the development of a Wilms tumor, most do not directly cause it. Some children with several risk factors never develop a tumor, while others with no known risk factors do.
Most often, Wilms tumor is not inherited, but there can be genetic reasons for the tumor’s development.
Children may have a mutated (changed), damaged, or missing gene. This change can also cause other birth defects. About 15% of children with a Wilms tumor were born with other health problems.
Children with WAGR syndrome, a condition that causes a number of birth defects, have a 33% chance of developing Wilms tumor. WAGR stands for Wilms tumor, aniridia (no iris in the eye), genitourinary abnormalities (changes to the reproductive and urinary organs) or gonadoblastoma (a rare tumor of the reproductive organs), and mental retardation.
Beckwith-Wiedemann syndrome  is a condition that causes enlarged internal organs and limbs. Children with this syndrome have a higher risk of developing Wilms tumor, kidney cysts, and tumors of the liver (hepatoblastoma), pancreas, and adrenal glands.
Boys with Deny-Drash syndrome, a condition in which the male sex organs do not develop correctly, have a higher risk of developing Wilms tumor.
A small number of children with Wilms tumor have a relative in their family with the disease.
The next section in this guide is Symptoms and Signs , and it explains what body changes or medical problems this type of tumor can cause. Or, use the menu on the side of your screen to choose another section to continue reading this guide.