Alpha 1 Antitrypsin Deficiency

Alpha-1 antitrypsin deficiency is a disorder that can cause liver disease in adults and children, and lung disease in adults. The disorder is inherited, and symptoms usually start to occur between the ages of 20 and 50.

Symptoms of Alpha-1 Antitrypsin Deficiency

Early symptoms will include shortness of breath and wheezing, though other symptoms such as weight loss, fatigue, abnormalities in vision and recurring respiratory infection may also occur. Once lung disease advances it may also lead to emphysema, which can lead to difficulty breathing and a hacking cough.

In the case of liver disease due to alpha-1 antitrypsin deficiency (which occurs in about 10% of children and 15% of adults who have the deficiency) the signs may include swollen legs, yellowing skin and a swollen abdomen.

The Genetics Behind Alpha-1 Antitrypsin Deficiency

The deficiency is inherited and is caused by SERPINA1 gene mutations. This is the gene responsible for making a certain protein (alpha-1 antitrypsin) that can protect the body against powerful enzymes.

The most common version of the SERPINA1 gene will produce normal levels of the alpha-1 antitrypsin protein, and most people have two copies of this version of the gene known as MM. However, there are other versions of the gene which lead to reduced levels of alpha-1 antitrypsin. The S version of this gene produces low levels, as does the Z version.

If an individual has a ZZ version of the gene then they will usually have alpha-1 antitrypsin deficiency, and those with the SZ combination will be at an increased risk of developing a lung disorder.

Many people have one copy of the S or Z version of the gene, but those with the combination MS or MZ usually have enough alpha-1 antitrypsin to protect their lungs and stay healthy.