Alpha-1 Antitrypsin Deficiency (Alpha-1)
Is a genetic/hereditary condition that leads to decreased circulating levels of alpha-1 antitrypsin (AAT) and significantly increases the risk of serious lung disease in adults and liver disease in infants, children and adults. Over 100 abnormal alleles have been identified for the AAT gene and of these about 1/3 are known to cause deficiency. The most common abnormal genes are the S and Z alleles, named according the speed of migration in an isoelectric focusing gel. Normal genes are labeled M (e.g.: M1, M2, M3, M4). Some abnormal alleles lead to a non-translatable gene product and therefore produce no AAT, these are the Null alleles. The most common genotype associated with Alpha-1 is ZZ (also referred to as PiZ). There are about 100,000 people with the ZZ phenotype in the US although less than 10% have been detected to date. AAT is a protein with potent protease inhibitor activity. The main function of AAT is to protect normal lung tissue from proteolytic attack during inflammation, such as that caused by infection and inhaled irritants such as tobacco smoke.
Alpha-1 has been identified in virtually all populations and ethnic groups. It is estimated that about 1 in every 2,500 Americans have Alpha-1. Individuals with Alpha-1 may remain healthy throughout their lives. Early diagnosis and avoidance of risk factors, such as cigarette smoking, can help prevent Alpha-1 from causing disease.
An estimated 20 million people have one normal and one defective AAT gene (carriers). Carriers may pass the defective gene on to their children and there is evidence for some increased risk of lung and liver disease in carriers, as well.
Alpha-1 can lead to emphysema and is often misdiagnosed as asthma or smoking-related Chronic Obstructive Pulmonary Disease (COPD). It is critical to remember that Alpha-1 is a laboratory diagnosis, not a clinical diagnosis. You can’t definitively make the diagnosis based on the patient’s medical history or physical examination. Diagnosis is made by a simple blood test.
Alpha-1 is the most common known genetic risk factor for emphysema and COPD.
About 3% of all people diagnosed with COPD may have undetected Alpha-1.
Alpha-1 can lead to liver disease. The most serious liver diseases are cirrhosis and liver cancer.
Airway pH: why measure
Until the introduction of Restech’s Dx–pH Measurement System, accurate, real-time measurement of airway pH was not possible. Physicians relied largely on subjective and empiric drug trials to confirm a diagnosis.
Acidic or alkaline extremes cause damaging effects in the airway and even worse damage to the lungs. The longer and more severe the exposure, the greater the corresponding damage. Complicating the effects of extreme pH is the similarity in symptoms and visual appearance of the epithelium. Likewise, allergies, vocal abuse, sleep apnea and laryngopharyngeal reflux can manifest as symptoms that are difficult, if not impossible, to differentiate.