People with the MZ genotype do not have severe AATD but are genetic carriersAn Alpha-1 Carrier is a person who has one normal ATT gene (M) and one defective AAT gene (usually S or Z). It does NOT mean you cannot get sick. More of the Z mutation. The Z mutation is a deficiency allele (version of the gene) that reduces the quantity of alpha-1 antitrypsin (AATalpha-1 antitrypsin More) in the blood, and causes AATD in people with two mutations (e.g. ZZ, SZ). The MZ genotype is not associated with an increased risk for lung disease in nonsmokers. Higher risk is seen in MZ individuals who smoke. A slightly increased risk for liver disease has been seen in MZ populations.
Alpha-1 at MUSC – Genetic Counseling
Because Alpha-1 is a genetic condition, your result means that your relatives are at increased risk to also have abnormal alpha-1 genes. We encourage you to make your family members and any reproductive partner aware of your result and the availability of testing. Reproductive partners of people with abnormal alpha-1 genes should be offered testing to assess risk to children.
Z:
What is Your Phenotype and What Does it Mean? – Kimberly Foil, MS, CGC, Genetic Counseling Program, Alpha-1 Foundation; Division of PulmonaryMedical term referring to the lungs. and Critical Care Medicine, Medical University of South Carolina (MUSC)
• the most common clinically significant allele
• causes misfolding of antitrypsin in the liver – making normal quantities of the protein but it misfolds, gets stuck to others and forms polymers which get stuck in the liver.
• 85% trapped in the liver
• originated in Scandinavia
• estimated that 2-3% of people in North America have one copy of the Z allele
The management of individuals with the PI*MZ genotype, characterized by mild or moderate AATalpha-1 antitrypsin More deficiency, is less clear than of those with the most common severe deficiency genotype (PI*ZZ). Recent genetic data suggest that the PI*MZ genotype may be significantly more prevalent than currently thought. The only specific treatment for lung disease associated with severe AATD is the intravenous infusion of AATalpha-1 antitrypsin More augmentation therapy, which has been shown to slow disease progression in PI*ZZ individuals. There is no specific evidence for the clinical benefit of AATalpha-1 antitrypsin More therapy in PI*MZ individuals, and the risk of emphysemaObstructive airway disease in which the walls of the alveoli (air sacs) are damaged or destroyed. More development in this group remains controversial. As such, current guidelines do not support the use of AATalpha-1 antitrypsin More augmentation in PI*MZ individuals.
Alpha-1 antitrypsin (AAT) augmentation therapy in individuals with the PI*MZ genotype: a pro/con debate on a working hypothesis – BMC PulmonaryMedical term referring to the lungs. More Medicine
The use of IV augmentation therapy with plasma-derived alpha1-antitrypsin (AATalpha-1 antitrypsin More) has become the standard of care for the treatment of pulmonaryMedical term referring to the lungs. More disease associated with the severe genetic deficiency of AATalpha-1 antitrypsin More. The Medical and Scientific Advisory Committee of the Alpha-1 Foundation has become aware that physicians are prescribing this expensive blood product for the treatment of individuals with a single abnormal AATalpha-1 antitrypsin More gene, primarily the PIMZ genotype. We are aware of no evidence that such therapy is effective in this patient population. The most important therapeutic interventions in such patients remain smoking cessation and elimination of other risk factors for lung disease. This commentary discusses the treatment of AATalpha-1 antitrypsin More deficiency and the concerns regarding treatment of PIMZ individuals. We conclude that clinicians should avoid prescribing augmentation therapy for this heterozygote population.
alpha1-Antitrypsin augmentation therapy for PI*MZ heterozygotes: a cautionary note – National Library of Medicine
Resources
- Am I an Alpha-1 Carrier? – Alpha-1 Foundation