title: Identification and characterisation of eight novel SERPINA1 Null mutations.
abstract: BACKGROUND
  Alpha-1 antitrypsin (AAT) is the most abundant circulating antiprotease and is a member of the serine protease inhibitor (SERPIN) superfamily. The gene encoding AAT is the highly polymorphic SERPINA1 gene, found at 14q32.1. Mutations in the SERPINA1 gene can lead to AAT deficiency (AATD) which is associated with a substantially increased risk of lung and liver disease. The most common pathogenic AAT variant is Z (Glu342Lys) which causes AAT to misfold and polymerise within hepatocytes and other AAT-producing cells. A group of rare mutations causing AATD, termed Null or Q0, are characterised by a complete absence of AAT in the plasma. While ultra rare, these mutations confer a particularly high risk of emphysema.
  
  
  METHODS
  We performed the determination of AAT serum levels by a rate immune nephelometric method or by immune turbidimetry. The phenotype was determined by isoelectric focusing analysis on agarose gel with specific immunological detection. DNA was isolated from whole peripheral blood or dried blood spot (DBS) samples using a commercial extraction kit. The new mutations were identified by sequencing all coding exons (II-V) of the SERPINA1 gene.
  
  
  RESULTS
  We have found eight previously unidentified SERPINA1 Null mutations, named: Q0cork, Q0perugia, Q0brescia, Q0torino, Q0cosenza, Q0pordenone, Q0lampedusa, and Q0dublin . Analysis of clinical characteristics revealed evidence of the recurrence of lung symptoms (dyspnoea, cough) and lung diseases (emphysema, asthma, chronic bronchitis) in M/Null subjects, over 45 years-old, irrespective of smoking.
  
  
  CONCLUSIONS
  We have added eight more mutations to the list of SERPINA1 Null alleles. This study underlines that the laboratory diagnosis of AATD is not just a matter of degree, because the precise determination of the deficiency and Null alleles carried by an AATD individual may help to evaluate the risk for the lung disease.
authors.affiliation: Centre for Diagnosis of Inherited Alpha-1 Antitrypsin Deficiency, Laboratory of Biochemistry and Genetics, Institute for Respiratory Disease, Fondazione IRCCS Policlinico San Matteo, Pavia, Italy. i.ferrarotti@smatteo.pv.it.|Department of Molecular Medicine, University of Pavia, Pavia, Italy. i.ferrarotti@smatteo.pv.it.
authors.forename: Ilaria
authors.initials: I
authors.lastname: Ferrarotti
authors.affiliation: Respiratory Research, Department of Medicine, Royal College of Surgeons in Ireland Education and Research Centre, Beaumont Hospital, Dublin, Ireland. tcarroll@rcsi.ie.
authors.forename: Tomás P
authors.initials: TP
authors.lastname: Carroll
authors.affiliation: Centre for Diagnosis of Inherited Alpha-1 Antitrypsin Deficiency, Laboratory of Biochemistry and Genetics, Institute for Respiratory Disease, Fondazione IRCCS Policlinico San Matteo, Pavia, Italy. stefania.ottaviani@yahoo.it.
authors.forename: Stefania
authors.initials: S
authors.lastname: Ottaviani
authors.affiliation: Department of Molecular and Translational Medicine, University of Brescia, Brescia, Italy. fra@med.unibs.it.
authors.forename: Anna M
authors.initials: AM
authors.lastname: Fra
authors.affiliation: Respiratory Research, Department of Medicine, Royal College of Surgeons in Ireland Education and Research Centre, Beaumont Hospital, Dublin, Ireland. geraldineobrienster@gmail.com.
authors.forename: Geraldine
authors.initials: G
authors.lastname: O'Brien
authors.affiliation: Respiratory Research, Department of Medicine, Royal College of Surgeons in Ireland Education and Research Centre, Beaumont Hospital, Dublin, Ireland. kmolloy@rcsi.ie.
authors.forename: Kevin
authors.initials: K
authors.lastname: Molloy
authors.affiliation: Department of Internal Medicine, Respiratory Disease Unit, Spedali Civili, Brescia, Italy. luciano.corda@spedalicivili.brescia.it.
authors.forename: Luciano
authors.initials: L
authors.lastname: Corda
authors.affiliation: Department of Pathology, Spedali Civili of Brescia, Brescia, Italy. daniela.medicina@spedalicivili.brescia.it.
authors.forename: Daniela
authors.initials: D
authors.lastname: Medicina
authors.affiliation: Respiratory Department, Mercy University Hospital, Cork, Ireland. dcurran@muh.ie.
authors.forename: David R
authors.initials: DR
authors.lastname: Curran
authors.affiliation: Respiratory Research, Department of Medicine, Royal College of Surgeons in Ireland Education and Research Centre, Beaumont Hospital, Dublin, Ireland. gmcelvaney@rcsi.ie.
authors.forename: Noel G
authors.initials: NG
authors.lastname: McElvaney
authors.affiliation: Centre for Diagnosis of Inherited Alpha-1 Antitrypsin Deficiency, Laboratory of Biochemistry and Genetics, Institute for Respiratory Disease, Fondazione IRCCS Policlinico San Matteo, Pavia, Italy. m.luisetti@smatteo.pv.it.|Department of Molecular Medicine, University of Pavia, Pavia, Italy. m.luisetti@smatteo.pv.it.
authors.forename: Maurizio
authors.initials: M
authors.lastname: Luisetti
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D008168:Lung / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D009154:Mutation; D010641:Phenotype; D015842:Serine Proteinase Inhibitors / Q000235:genetics*; D000515:alpha 1-Antitrypsin / Q000235:genetics*; D019896:alpha 1-Antitrypsin Deficiency / Q000235:genetics* / Q000503:physiopathology
chemical_list: D015842:Serine Proteinase Inhibitors; D000515:alpha 1-Antitrypsin