The pathological Trento variant of alpha-1-antitrypsin (E75V) shows nonclassical behaviour during polymerization
Severe alpha?1?antitrypsin deficiency (AATD) is most frequently associated with the alpha?1?antitrypsin (AAT) Z variant (E342K). ZZ homozygotes exhibit accumulation of AAT as polymers in the endoplasmic reticulum of hepatocytes. This protein deposition can lead to liver disease, with the resulting low circulating levels of AAT predisposing to early?onset emphysema due to dysregulation of elastinolytic activity in the lungs. An increasing number of rare AAT alleles have been identified in patients with severe AATD, typically in combination with the Z allele.