Alpha-1-antitrypsin genotyping with mouthwash specimens

alpha (1)-antitrypsin (alpha (1)-AT) deficiency is diagnosed as a two-stage procedure (concentration and phenotype), However the latter does not provi de clues to the presence of null genes without family studies and obtaining blood from patients at a distance often proves difficult. The aim of the s tudy was to assess the feasibility of genotyping alpha (1)-AT using buccal cells. Mouthwash specimens mere sent by 84 patients (with a variety of phenotypes of al-antitrypsin) through the post. Deoxyribonucleic acid (DNA) was isolat ed from buccal cells in each sample and subjected to polymerase chain react ion (PCR) using a genotyping kit to detect the S and Z alleles. Eighty-three of 84 samples received were suitable for amplification. The sp ecific primers successfully identified the S and Z alleles in each case. Ho wever, five of the 35 samples obtained from patients thought to be Z allele homozygotes were found to be heterozygotes for another severe deficiency a llele. These data confirm the feasibility of "at distance" testing for al-antitryp sin deficiency alleles using buccal cells from mouthmash samples. The resul ts raise the possibility that other deficiency alleles are more common than has previously been suspected.