PURPOSE: Non-MM phenotype's serum concentration of alpha-1 antitrypsin (AAT) were reported to be lower than the levels in MM phenotype subjects. This study is to determine the correlation between serum AAT levels and phenotype in less commonly reported phenotypes.
METHODS: A prospective chart review of patients in an outpatient Pulmonary Medicine clinic in Easter Kentucky, included all patients who were screened for AAT deficiency between JUN 2006 through APR 2008. Only subjects tested positive for a non-MM phenotype and had reports of serum AAT concentration levels on records were included in the study. The data were then analyzed comparing the average AAT level and the reported phenotypes.
RESULTS: A total of 147 subjects met the inclusion criteria. The most common non-MM phenotypes found were MS (78 subjects), MZ (48 subjects), ZZ (7 subjects) followed by GM, SS, FM, IS, FF, CM, GS, SZ, IM and EM. The lowest average levels were found in subjects with ZZ (22.4 mg/ dL), SZ (26 mg/dL) followed by SS (74 mg/dL). The highest levels were found in subjects with FF (299 mg/dL), EM (253 mg/dL) followed by IM (156 mg/ dL).
CONCLUSION: This study confirms previous studies findings that the Z and S alleles are responsible for the lowest AAT levels, and reports that other rare phenotypes are associated with higher AAT levels mainly the E, I, G, C, and F alleles.
CLINICAL IMPLICATIONS: There are many AAT phenotypes that are infrequantly reported in the literature and more prevalent in Eastern Kentucky. These results should be validated and more screening of affected subject need to be proactively tested to combine the effect of those phenotypes and existence of clinically significant airway obstruction. In summary, as more cases are detected, a better understanding of rare phenotypes could aid in the cumulative evaluation of patients and their families.
DISCLOSURE: Firas Koura, Consultant fee, speaker bureau, advisory committee, etc. Baxter, CSL; No Product/Research Disclosure Information