Rapid genotyping of alpha 1 antitrypsin deletion mutation (PI*Mmalton) using bi-directional PCR allele-specific amplification.

Alpha 1 antitrypsin deficiency (AATD) is a well recognized genetic risk factor for pulmonary disease and less common liver disease. The two most common deficiency alleles worldwide PIS and PIZ can be easily detected using several molecular methods. However, there are at least 30 other AATD variants, which are only detectable by alpha 1 antitrypsin (AAT) gene sequencing and, therefore, seem to be more under-recognized than the PIS and PIZ alleles. PIMmalton is the most frequent AATD variant in different regions of the Southern Mediterranean basin countries, where its prevalence seems to prevail over PIS and PIZ. In this work, we report the development of a simple PCR-based analysis designed for the detection of the PIMmalton deficiency alleles using two specific primers. A one-tube reaction enables the distinction between the different genotypes. This reliable, easy, fast, and low-cost technique might be useful for laboratories involved in the study of AATD-related diseases, especially those of the Southern Mediterranean basin area with modest budget or where sophisticated equipment is not available. This will allow larger targeted screening for PI*Mmalton in order to better understand this mutation epidemiology and its origin.