2. Overview of Disease
• Alpha-1-antitrypsin
deficiency leads to a
condition known as Chronic
Obstructive Pulmonary
Disease (COPD) or
emphysema of the lungs.
• Clinically
– Shortness of breath
– ‘barrel chest’
3. Overview of Disease
• Liver Disease
– Alpha 1 Antritrypsin secreted from the liver
– The improperly folded protein cannot be secreted,
and buildup causes liver damage.
• Clinically
– Cirrhosis may develop in patients with alpha-1-
antitrypsin deficiency
– Reduced liver function
– Inflammation of liver severe fibrosis of the liver
– Liver failure
4. Genotype
• There are many variants for alpha1 AT
Deficiency
• Most common in the United States is the S
variant (SS) others include MS, MZ, or ZZ
• The Z variant is due to a substitution on
the distal end of chromosome 14,
(Location: 14q32.1 ) worst variant
• Most commonly the substitution is
Glutamic acid is replaced by lysine at
position 342 (Glu342Lys).
5. Protein Function
• The normal function of the alpha 1
antitrypsin is to counteract the effects of
neutrophil elastase
– Enzyme in the lung used to destroy bacteria,
cellular debri
– Without the inhibition of neutrophil elastase,
the enzyme destroys tissue surrounding
alveoli, causing trapped air emphysema.
– A1AT functions in other organs, but main
damage occurs in lungs
9. Changes in Function of Protein
• The variant of glutamic acid to lysine
causes a slight difference in the folding of
the protein which inhibits normal function.
• The amino acid interacts with surrounding
amino acids causing the abnormal fold.
10. Changes in Phenotype
• The abnormal folding inhibits proper
function of the protein. It therefore cannot
escape the liver, causing liver disease and
cirrhosis due to scarring. The non-
functioning protein cannot protect the
lungs against the enzyme nuetrophil
elastase, and emphysema develops.
11. Works Cited
Lai, E. C.; Kao, F.-T.; Law, M. L.; Woo, S. L. C. :
Assignment of the alpha-1-antitrypsin gene
and a sequence-related gene to human
chromosome 14 by molecular hybridization.
Am. J. Hum. Genet. 35: 385-392, 1983.
PubMed ID : 6602546
• Bethesda (MD). Genes and disease. National
Library of Medicine (US), NCBI.
• Axelsson, U.; Laurell, C. B. : Hereditary
variants of serum alpha-1-antitrypsin. Am. J.
Hum. Genet. 17: 466-472, 1965.
PubMed ID : 4158556