Characterization of three new variants PiQ0, PiQ0 and PiQ0 in patients with severe alpha-1 antitrypsin deficiency.

Background: The clinical and molecular characteristics of three patients with previously unreported mutations associated with severe alpha-1 antitrypsin deficiency (AATD) are described. The pathophysiology of the chronic obstructive pulmonary disease (COPD) present in these patients was characterized through clinical, biochemical, and genetic examinations.

Case Presentations: Case 1: A 73-year-old male with bilateral centri-to panlobular emphysema and multiple increasing ventrobasal bullae and incomplete fissures, COPD (Global Initiative for Chronic Obstructive Lung Disease (GOLD) grade III B), progressive dyspnea on exertion (DOE), AAT level of 0.1-0.2 g/L. Genetic testing revealed a unique mutation: Pi*Z/c.1072C > T. This allele was designated PiQ0. Case 2: A 47-year-old male with severely heterogenous centri-to panlobular emphysema concentrated in the lower lobes, COPD GOLD IV D with progressive DOE, AAT <0.1 g/L. He also had a unique Pi*Z/c.10del mutation in . This allele was named PiQ0. Case 3: A 58-year-old female with basally accentuated panlobular emphysema, GOLD II B COPD, progressive DOE. AAT 0.1 g/L. Genetic analysis revealed Pi*Z/c.-5+1G > A and c.-472G > A mutations in . This variant allele was named PiQ0.

Conclusions: Each of these patients had a unique and previously unreported mutation. In two cases, AATD and a history of smoking led to severe lung disease. In the third case, timely diagnosis, and institution of AAT replacement stabilized lung function. Wider screening of COPD patients for AATD could lead to faster diagnosis and earlier treatment of AATD patients with AATD which could slow or prevent progression of their disease.