Researchers examined 100 people suffering from herniated disks in their backs  Five of them were found to have a defect in a particular gene  The researchers also examined 100 people who had no problems with the disks in their backs; none had the genetic defect
They concluded that the genetic defect increases the likelihood of herniated disks
The researchers also examined a group of 100 people who did not have the defective gene; 80 were found to have herniated disks in their backs.