Carrier for Alpha-1 Antitrypsin
Dear Dr. Mahler:
I am 74 years old and was recently hospitalized for a flare-up of my COPD due to a chest cold. The hospital doctor referred me to the local pulmonologist, who told me that my breathing tests show “very severe” COPD. She tested me for alpha-1 antitrypsin deficiency. At my follow-up appointment, she gave me a copy of the test result and told me that I had a normal level (265 mg/dL), but that my Genotype was MF. Based on my discussion with the pulmonologist, I understand this means that I am a carrier for alpha-1 antitrypsin deficiency. Can you help explain what all of this means?
Otherwise, I am doing fine. I take Advair in the round disk and Incruse powder, and do maintenance pulmonary rehab at the nearby hospital.
Gloria from Northbrook, IL
Thanks for your question about being a carrier for alpha-1 antitrypsin deficiency, a hereditary form of emphysema. I will try to provide a simple answer to your question on a topic that can be complicated.
Here is a brief review of the alpha-1 antitrypsin protein. It is made in the liver and released into the blood. One of its functions is to prevent damage to the lung. Some defects in the gene (called an allele) block the release of the protein into the blood resulting in a lower blood level called a deficiency. This makes the lungs more susceptible to injury from cigarette smoking or inhaling irritants in the air. This can cause emphysema which may develop in someone as early as in his/her 40s. The other conditions that can occur in alpha-1 antitrypsin deficiency are shown in the figure.
Structure of the alpha-1 antitrypsin protein
The normal allele (part of a gene) for alpha-1 antitrypsin is called M. Normally, a person is MM. This means that the person inherited one M allele from each parent. The most common abnormal alleles are called S and Z.
You have one normal allele – M, and one abnormal allele F. The good news is that you do not have a deficiency of alpha-1 antitrypsin, and therefore no changes are necessary in your treatment. You may wish to share the test results with family members.
I agree with your pulmonologist that you are a carrier for alpha-1 antitrypsin deficiency. Current evidence suggests that those with the F allele have normal levels of the alpha-1 protein in the blood, but that it may not have totally normal function. As I mentioned earlier in this response, you should continue to use your inhalers and stay active with continued participation in pulmonary rehabilitation.
The Alpha-1 Foundation website [https://www.alpha1.org] is an excellent source of information about the disease.
Donald A. Mahler, M.D.
Conditions associated with Alpha-1 antitrypsin deficiency