FAQ’s and Facts
What is Alpha-1 Antitrypsin?
Alpha-1 antitrypsin is an important protein produced by the liver. Once the protein is released into the bloodstream and travels to the lungs, it protects the lungs from the destructive actions of common illnesses and exposures, particularly tobacco smoke.
What is Alpha-1 Antitrypsin Deficiency?
Alpha-1 antitrypsin deficiency is an inherited disorder that may cause lung or liver disease. Adults with a deficiency of this protective protein often suffer from progressive lung damage known as emphysema. While the common form of emphysema is seen in otherwise healthy individuals who have smoked for many years, this alpha-1 antitrypsin deficiency form of emphysema may occur at an unusually young age and often after only minimal exposure to tobacco smoke.
What is Emphysema?
Emphysema is an irreversible condition that results from the destruction of air sacs in lungs. These air sacs, known as alveoli, allow for the absorption of oxygen into the bloodstream and for the elimination of carbon dioxide waste. If they are destroyed, shortness of breath and a chronic cough may result. Not everyone with alpha-1 antitrypsin deficiency will develop emphysema. In most cases the amount of alpha-1 antitrypsin present will be enough to protect the lung from severe destruction.
What is Cirrhosis?
Cirrhosis is a chronic degenerative disease of the liver. Alpha-1 antitrypsin deficiency is a risk factor for cirrhosis. The liver deteriorates as the lobes become bibulous and fat accumulates. The liver becomes unable to detoxify drugs and alcohol. Vitamin absorption is inhibited. Both gastrointestinal bilirubin and hormonal metabolic functions are affected. Symptoms of cirrhosis include nausea, weakness, abdominal pain, weight loss and flatulence.
What is Panniculitis?
Panniculitis is an inflammation of the fat beneath the skin, causing the skin to harden and form lumps, patches or lesions. People with Alpha-1 antitrypsin deficiency have an increased risk of developing Panniculitis.
Smoking is the number one risk factor. Cigarette smoke renders the available alpha-1 antitrypsin useless. Smoking cessation can improve the survival rate.
Any type of irritant, bacteria or virus can also further decrease lung health.
How is Alpha-1 Antitrypsin Deficiency Diagnosed?
Diagnosis involves two tests. The first is a simple blood test to detect levels of alpha-1 antitrypsin circulating in your blood. Most, but not all people with levels less than 30% of normal will develop emphysema. Levels above 30% of normal are seen to give adequate protection unless the person is a heavy smoker. A blood test is recommended if you have relatives, especially siblings, who have been diagnosed with alpha-1 antitrypsin deficiency or if there is a family history of early emphysema, with or without smoking.
The second test is called phenotyping and is a genetic test. Phenotyping is only done when alpha-1 levels come back low. Results will indicate which alpha-1 genes you have. M refers to the normal gene. S, Z, and Null genes are the most common ones that cause A1AD. Null gene produces no detectable levels of AAT. They are at greatest risk of developing emphysema, yet none have suffered liver damage as a result of A1AD.
A person with the phenotype “MM” has normal alpha-1 function. A person with the phenotype “MZ” or “MS” is called a heterozygote. Heterozygotes have a mildly increased risk of lung and liver disease but are generally normal. A person with two deficient genes, like “ZZ” or “SZ” is considered to have alpha-1 antitrypsin deficiency.
How did I inherit this deficiency?
You inherit one gene from each parent at birth from a choice of two. If one of your parents had normal levels of AAT (i.e. phenotype MM) and the other had very low levels (i.e. phenotype ZZ) then your phenotype would be MZ (one gene from each parent) and your lungs would be protected but you would still be a carrier. If both parents have the MM or ZZ phenotype then you would either be MM or ZZ. Alpha-1 antitrypsin levels usually depend on the phenotype, as listed below:
MM: normal level
MS: 80% of normal
MZ: 60% of normal
SZ: 40% of normal
ZZ: 10% of normal level
For more answers to these and other FAQ’s, take a look at the European Lung Foundation’s factsheet about Alpha1 Antitrypsin Deficiency, available here.