Alpha-1 antitrypsin deficiency

Alpha-1 antitrypsin (A1AT) deficiency is a common inherited condition caused by a lack of a protease inhibitor (Pi) normally produced by the liver. The role of A1AT is to protect cells from enzymes such as neutrophil elastase.

Genetics
located on chromosome 14
inherited in an autosomal recessive / co-dominant fashion*
alleles classified by their electrophoretic mobility - M for normal, S for slow, and Z for very slow
normal = PiMM
homozygous PiSS (50% normal A1AT levels)
homozygous PiZZ (10% normal A1AT levels)

Features
patients who manifest disease usually have PiZZ genotype
lungs: panacinar emphysema, most marked in lower lobes
liver: cirrhosis and hepatocellular carcinoma in adults, cholestasis in children

Investigations
A1AT concentrations

Management
no smoking
supportive: bronchodilators, physiotherapy
intravenous alpha1-antitrypsin protein concentrates
surgery: volume reduction surgery, lung transplantation

*trusted sources are split on which is a more accurate description

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