Affected individuals rarely survive to the age of 30. Failure to recognize the disorder early in life results in mental retardation . Many states require all newborns to be screened for this disease. AAT deficiency is a disorder seen in about 1 out of 10,000 births. The normal function of the protein is to inhibit enzymes which escape from white blood cells in the process of destroying invading bacteria.
Affected individuals are much more likely to develop emphysema than usual.
Sickle cell anemia is a disorder common in individuals with an African ethnic background. The high frequency of the gene probably relates to the fact the the heterozygotes are resistant to malaria . The homozygotes have a predominance of an abnormal hemoglobin in their red blood cells. This abnormal protein causes the red blood cells to assume abnormal shapes and to lyse in small blood vessels under conditions of reduced oxygen pressure. This enzyme is important for the normal function of lymphocytes which are the primary components of the immune system.