SERPINA1 and chronic obstructive pulmonary disease: Worldwide, it is estimated that there are at least 116 million alpha one carriers (PiMS and PiMZ: M, normal genetic Pi Type; S, lower than normal; Z, lower than S) and 3.4 million with deficiency allele combinations (PiSS, PiSZ, and PiZZ) 14, 17, all of whom are sensitive to environmental conditions to develop COPD.