Why Family Testing Is Important in Alpha₁ Antitrypsin Deficiency

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.

References:
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.
2009;3:193-204.
2. Alpha-1 Foundation website. What is Alpha-1? http://alpha-1foundation.org/what- is-
alpha-1. Accessed April 21, 2017.