SERPINA1 Homozygous ZZ Genotype Positive

**Semantic type:** Laboratory or Test Result

**Definition:** An indication that homozygous expression of the SERPINA1 Z allele has been detected in a sample. The Z allele is both a loss of function mutation and a toxic mutation. It encodes a form of the alpha-1-antitrypsin protein with an E366K substitution that is not secreted effectively and forms aggregates in the endoplasmic reticulum (ER), which decreases the amount of circulating enzyme and interferes with the protein folding machinery, leading to ER stress.

**Synonyms:** - A1AT ZZ Phenotype - Alpha-1 Protease Inhibitor Homozygous Z Mutation - Alpha-1 Protease Inhibitor Homozygous Z Mutation Positive - PiZZ - PiZZ Genotype - PiZZ Genotype Positive - SERPINA1 Homozygous ZZ Genotype - ZZ-AAT Genotype Positive