It is noteworthy that AAT levels were similar in all asymptomatic ZZ AAT cases independent of age (0.27 ± 0.05 mg/ml, n = 48, mean age 32 years and 0.2 ± 0.03 mg/ml, n = 10, mean age 53 years), while ZZ COPD patients had 25% higher plasma AAT levels compared to asymptomatic ZZ cases, although this was not statistically significant. The gene discussed is SERPINA1; the disease is chronic obstructive pulmonary disease.