The plasma levels of this class of variants are undetectable by conventional techniques such as nephelometry and IEF, and as such, these mutations are classically thought to result in a complete absence of AAT production and therefore a high risk of developing emphysema.32 While the consequence of the null alleles is unified, that is, undetectable plasma levels of AAT, the mutational events from which they arise vary from gene deletions, premature stop codon insertions, to mRNA degradation. The gene discussed is SERPINA1; the disease is pulmonary emphysema.