Genes And Medicine
1. AAT (alpha-1-antitrypsin) is a glycoprotein that inhibits the enzyme elastase (produced by white
blood cells). Elastase breaks down elastic tissue in the lungs, causing emphysema. The Z-allele of
AAT is a mutant gene, resulting in the production of faulty AAT and therefore emphysema.
2. Working AAT can be produced using transgenic organisms:
a. Mature eggs are removed from the ovary of a sheep and fertilised in vitro.
b. Plasmids containing the gene for AAT are inserted into the cells with a micropipette.
c. The embryos are developed to the 16-cell stage and inserted into surrogate mothers.
d. Some of the lambs produced will (hopefully) be transgenic. AAT will be produced in the
milk of the transgenic sheep.
3. People with the Z-allele can be treated using an aerosol spray containing the AAT in liposomes.
This will temporarily inhibit the elastase and give temporary relief from emphysema. There is,
however, no permanent cure, and lifelong treatment…