If you inherit only one, you won't get sick. You will, however, be a carrier to the next generation. This means that you may pass on the mutated gene to your children without ever showing any symptoms yourself. Your children will be at risk for getting the disease only if they inherit the disease-causing gene mutation from both you and their other parent. An example of a recessive disorder is sickle cell anemia, which was discussed in the last chapter.
Some disorders occur when healthy genes become damaged.
Gene damage can be caused by exposure to radiation or by a viral infection. It also can happen if you come into contact with cancer-causing substances, called carcinogens . Depending on which genes have been damaged, and how many, different disorders may be triggered. Some people's genes appear to be more easily damaged than others. Such people are at higher risk for disorders caused by damage to healthy genes.