Some human diseases are caused by a defective gene. An example is cystic fibrosis, a disease of mucous glands throughout the body that usually develops during childhood and makes breathing increasingly difficult. IF a child receives two copies of the defective gene call the CF gene -- one copy from each parent -- then the child will develop the disease. Biotechnology is used in several ways in detecting, diagnosing and treating cystic fibrosis.
Genetic testing or "screening" enables healthy people to know whether they carry one copy of the CF gene. If both potential parents have one copy each of the CF gene, then the genetic counselor can provide information and help assess whether the couple may have a child who will develop cystic fibrosis.
Genetic testing can alert parents their child has two copies of the CF gene, permitting diagnosis even before the disease develops in the child.
Children with cystic fibrosis can enjoy some relief from the mucus buildup in their lungs by breathing in a mucus-breaking drug made with recombinant DNA technology. The drug contains a protein that chews up the DNA so the mucus is easier to remove from the lungs by coughing.
An experimental approach to curing cystic fibrosis uses a genetically engineered cold virus that delivers to the patient's lung cells a working version of the defective gene. The new gene enables lung cells to make the protein that is lacking in cystic fibrosis patients.