Strategy for the active search of patients with Alpha1 antitrypsin deficiency (A1AD)
The services of Internal Medicine and Clinical Analysis Laboratory of Asunción Klinika have set up a strategy for the early detection of Alpha 1 Antitrypsin deficiency, a rare disorder of genetic origin which confers a predisposition to developing diseases such as pulmonary emphysema or various types of liver diseases. A simple blood test carried out on risk groups (patients with COPD, with asthma or other respiratory diseases) can detect the existence of this deficiency and enable measures to be taken to prevent the development of the disease.
Alpha-1-antitrypsin deficiency (A1ATD) is the most frequent potentially fatal congenital disease in adulthood. In spite of this, it continues to be an under diagnosed disease and when it comes to its diagnosis, it is usually made in very advanced phases with the therapeutic limitations that this brings. It is estimated that Alpha-1 Antitrypsin Deficiency (in its most severe form) affects 1 in every 2500 people. According to the Spanish Registry, there are around 500 diagnosed ZZ patients in our country, of the 12000 of those estimated to suffer from it.
In addition, it is estimated that there are approximately 150,000 patients with different genotypes (SZ...) which, although they will not suffer from the most serious form of the disease, they may end up showing the disease in different intensities, and they could benefit from specific health interventions if they know about it in time.
A simple routine blood test, as simple as carrying out a cholesterol test, enables the detection of the Alpha 1 Antitrypsin deficiency. Once detected, the diagnoses should be extended with the genetic study. There is also the possibility of carrying out the genetic study directly in those highly suspicious cases or when the inflammatory situation may cause falsely elevated results.
Experts, as well as the scientific organisations linked to lung and liver health and to Alpha 1 antitrypsin deficiency, categorically recommend carrying out the Alpha 1 antitrypsin deficiency test to the following risk groups:
All patients with COPD
Adults with partially reversible asthma
Adults with bronchiectasis, chronic bronchitis or non- reversible asthma.
People with a family history of Alpha 1 Antitrypsin deficiency.
History of dyspnoea and chronic cough in various members of a family.
Patients with liver alterations or disease of an unknown or dubious origin.
Decrease in peak of alpha-1 protein in the proteinogram.
Those affected by necrotizing panniculitis.
Once the analysis to establish AAT values has been carried out, a phenotype study will be performed on individuals who have lower than normal concentrations, and another genotype study on those individuals who reflect discrepancies between the AAT values and the technically non-deficient phenotypes.
What is Alpha 1 Antitrypsin Deficit?
The Alpha 1 Antitrypsin Deficit is a hereditary genetic condition which is passed on by simple mendelian inheritance through two alleles, one from each parent, that the children receive 50%. When one of the parents passes the condition on, there is a partial Deficiency; and when both parents pass it on, the deficiency is more severe.
The S and Z alleles encode abnormal proteins, which polymerise in the liver, so that 80-90% of the AAT-Z molecules and 40-50% of the AAT-S are kept grouped in the liver, and are not released into the bloodstream to carry out their function of slowing down the destructive effects of the proteases.
Alpha-1 Antitrypsin Deficiency (A1ATD) presents a predisposition to developing diseases throughout life, mainly pulmonary emphysema and various liver diseases, so it should be considered a systemic disease. Whilst liver diseases are related to the accumulation of intrahepatic polymers, the development of emphysema is favoured by the low plasma and tissue concentrations of AAT, insufficient to protect the connective tissue of the lung from the destructive effects of the proteases.
In practice, the risk of the disease presenting itself in its severe form is limited to ZZ phenotypes (96%). Smoking is the most significant risk factor, which indicates that A1ATD by itself, is not usually sufficient to develop the disease and other genetic and environmental factors must exist.