Why Family Testing Is Important in Alpha1 Antitrypsin Deficiency

December 11, 2017

11/27/17 Posted By: CSL Behring LLC

Why Family Testing Is Important in Alpha1 Antitrypsin Deficiency

Alpha1 antitrypsin (A1AT) deficiency, commonly known as Alpha-1, is a progressive condition affecting the lungs.Because the physical symptoms of Alpha-1 resemble those of other serious lung diseases, it is often missed or misdiagnosed. Alpha-1 can have significant consequences, as it is often the root cause of other serious lung diseases.

Alpha-1 is hereditary, which means it can be passed on from parents to their children through DNA, or genes. People who have Alpha-1 have inherited 2 deficient genes, 1 from each parent. People with 1 normal gene and 1 defective gene are called “carriers.” Carriers may pass the defective gene on to their children.

According to the Alpha-1 Foundation, there may be as manyas 19 million carriers of Alpha-1 in the United States. Because carriers typically don’t have symptoms, they are usually not aware they carry the defective gene. 

 To help explain the genetics of Alpha-1, let’s look at a hypothetical family in which both parents are carriers: Mom is an MZ and Dad is an MS.1


Each child born to this couple has the same chance to inherit 2 normal genes (MM), 1 normal and 1 defective gene (MS or MZ), or 2 defective genes (SZ). Let’s see what each of these gene combinations means in terms of the genetic and health status of each child.1

MM (Normal)­­means that the child does not have the disorder and does not carry any abnormal A1AT genes.1

MZ (Carrier)results in mild to moderate A1AT deficiency, meaning that the child may get disease symptoms and carries an abnormal A1AT gene. For a child with the MS (Carrier)combination, it is unclear whether there is a risk for getting disease symptoms, but the child does carry an abnormal A1AT gene. However, most studies do not show an increased risk for disease.1

SZ(Alpha-1)means the child has moderate to severe (SZ) Alpha-1 deficiency. The child could get the disease and carries 2 abnormal A1AT genes.1

In some cases, there may be other variants.1

Due to an increased understanding of the hereditary nature of Alpha-1, the Alpha-1 Foundation now recommends testing for parents, children, siblings, and extended family of anyone diagnosed with Alpha-1 or identified with an abnormal gene for Alpha-1. Talk to your doctor about your unique risk and testing for Alpha-1.

Read more here.

1. Petrache I, Hajjar J, Campos M. Safety and efficacy of alpha-1- antitrypsin augmentation
therapy in the treatment of patients with alpha-1- antitrypsin deficiency. Biologics.
2. Alpha-1 Foundation website. What is Alpha-1? http://alpha-1foundation.org/what- is-
alpha-1. Accessed April 21, 2017.

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