Skip to contentSkip to navigation

A1AT, AAT, Alpha-1-Antitrypsin


Most cells contain digestive enzymes in inactive form. To control their action, these enzymes must be neutralized. Alpha-1-antitrpysin (A1AT, AAT, A-1-antitrypsin) is a blood protein that protects the lungs and liver from damage that could be caused by activating the elastase in white blood cells, a normal body defence mechanism. Levels of alpha-1-antitrypsin (A1AT, AAT, A-1-antitrypsin) are determined by two copies of a gene, each responsible for the synthesis of half of the available alpha-1-antitrypsin (A1AT, AAT, A-1-antitrypsin). More specific tests (genotype) identify the nature of the genes present.

Levels of alpha-1-antitrypsin (A1AT, AAT, A-1-antitrypsin) below 30% of normal values indicate that the person has inherited at least one defective gene. There is therefore a risk of damage caused by the activation of the elastase in the lungs and liver (early pulmonary emphysema or cirrhosis). Lower levels can also be observed in other situations that lead to a general decline in serum proteins such as kidney disease, malnutrition and certain cancers.

Alpha-1-antitrypsin (A1AT, AAT, A-1-antitrypsin) is an “acute-phase protein”. Levels will increase under acute or chronic inflammatory conditions, infections and certain cancers. These acute-phase increases could temporarily mask an otherwise genetically depressed protein level.

Term of the Week

Predictive medicine

Medicine that links medical knowledge with data to predict a patient’s potential health problems. Examples include artificial intelligence and genetics.