title: Rapid detection of Mmalton α1-antitrypsin deficiency allele by real-time PCR and melting curves in whole blood, serum and dried blood spot samples.
abstract: BACKGROUND
  α1-Antitrypsin deficiency (AATD) is an autosomal codominant disorder associated with a high risk of developing lung and liver disease. The most common deficient alleles are known as Z and S. However, another deficient variant, called Mmalton, which causes a deficiency similar to variant Z, is considered to be the second cause of severe AATD in Spain. Nevertheless, the Mmalton allele is not recognizable by usual diagnostic techniques and therefore, its real prevalence is underestimated. We describe a rapid real-time PCR and melting curves assay designed for the detection of Mmalton AATD.
  
  
  METHODS
  We tested the applicability of this new technique for the identification of the Mmalton allele in AATD screening using whole blood, dried blood spot (DBS) and serum samples. Mmalton heterozygote and homozygote samples and samples without this allele were included in the study.
  
  
  RESULTS
  This new assay is able to detect homozygous and heterozygous genotypes in the same reaction and in a single step, giving matching results with those obtained by SERPINA1 gene sequencing.
  
  
  CONCLUSIONS
  This technology is optimal for working with small amounts of DNA, such as in DBS and even with residual DNA present in serum samples, allowing improvement in routine algorithms of AATD diagnosis or large-scale screening. This method will be useful for obtaining more in depth knowledge of the real incidence of the Mmalton variant.
authors.forename: Irene
authors.initials: I
authors.lastname: Belmonte
authors.forename: Luciana
authors.initials: L
authors.lastname: Montoto
authors.forename: Marc
authors.initials: M
authors.lastname: Miravitlles
authors.forename: Miriam
authors.initials: M
authors.lastname: Barrecheguren
authors.forename: Cristina
authors.initials: C
authors.lastname: Esquinas
authors.forename: Esther
authors.initials: E
authors.lastname: Rodríguez
authors.forename: Marina
authors.initials: M
authors.lastname: Giralt
authors.forename: Francisco
authors.initials: F
authors.lastname: Rodríguez-Frías
mesh_terms: D000465:Algorithms; D000483:Alleles; D001483:Base Sequence; D004247:DNA / Q000097:blood* / Q000737:chemistry / Q000302:isolation & purification; D059788:Dried Blood Spot Testing; D031541:Fluorescence Resonance Energy Transfer; D005456:Fluorescent Dyes / Q000737:chemistry; D005838:Genotype; D006579:Heterozygote; D006801:Humans; D060888:Real-Time Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D044366:Transition Temperature; D000515:alpha 1-Antitrypsin / Q000235:genetics*
chemical_list: D005456:Fluorescent Dyes; C043392:SERPINA1 protein, human; D000515:alpha 1-Antitrypsin; D004247:DNA