Alpha-1-antitrypsin Phenotyping and Genotyping

"Alpha-1-antitrypsin (A1AT) deficiency may manifest itself in a range of ways from liver disease in the neonatal period to lung disease in adult life depending on the mutation present (i.e. Z or S mutations). Whilst measurement of A1AT concentrations can be useful as a first line screen for deficiency, as A1AT is an acute phase protein, concentrations can approach the normal reference range in acutely ill subjects. Phenotyping, using isoelectric focusing, allows the mutation to be identified and the screening of siblings or other members of the family, who may be asymptomatic at the time.

A1AT genotype analysis is offered as an adjunct to the phenotyping service and for family studies. Homozygosity or heterozygosity for the Z and S mutations can be detected using a real-time Taqman assay. Other variants and null alleles are not detected by this method."