What is Alpha-1 Antitrypsin Deficiency?
Simply, Alpha-1 Antitrypsin Deficiency is a genetic condition that affects the lungs and the liver.
In "normal" people, the liver produces the Alpha-1 protein (AAT). This protein travels to the lung via the bloodstream and keeps the lungs from becoming inflamed because of tobacco smoke and other irritants. When the gene responsible for production and release of this protein into the bloodstream is not working properly, the AAT builds up in the liver and decreases in the lungs eventually leading to irreversible damage to the tissues.
The condition only develops if both parents pass on defective genes to their children. If only one parent is a carrier, then the children will not develop the condition, but they will become carriers. Research indicates that about 20 million people have one normal and one defective AAT gene. It is estimated that one in every 2,500 Americans have Alpha-1 and about one in every 5,000 to 7,000 people across North America. Alpha-1 is not bound by culture or ethnic group - although the condition is less prevalent in black and asian populations.
Alpha-1 can often be misdiagnosed as asthma or smoking-related COPD and is the leading risk factor for emphysema. It is estimated that approximately 3 percent of all people diagnosed with COPD may actually have underlying Alpha-1. It is because of these findings that the World Health Organization (WHO), the American Thoracic Society (ATS), and the European Respiratory Society (ERS) have collaborated and agreed that all patients diagnosed with COPD be tested for Alpha-1.
It's in the Genes
Specifically, the production and regulation of Alpha-1 is done by the SERPINA1 gene. There are three versions (known as alleles) of the SERPINA1 - the M gene, the S gene, and the Z gene.
Most people have two M genes (MM) in each cell. It is the mutation and combination of the other two allele types that can lead to symptoms. The S allele produces moderately low levels of AAT; the Z allele produces very small amounts of AAT.