title: [PI*S and PI*Z alpha 1-antitrypsin deficiency: estimated prevalence and number of deficient subjects in Spain].
abstract: OBJECTIVE
  Alpha-1-antitrypsin deficiency (AATD) is an hereditary disorder with increased risk of pulmonary emphysema and chronic liver diseases in children and adults. Since it is possible currently in Spain to apply alpha-1-antitrypsin replacement therapy to AATD patients, the objective of this study was to calculate the total number of subjects affected by PIS and PIZ AATD, and its phenotypic distribution. SUBJECTS, MATERIAL AND METHOD: Selection of published studies on allelic frequencies PIS and PIZ according to the following criteria: a) alpha-1-antitrypsin phenotyping performed by isoelectrofocusing; b) rejection of "screening studies"; c) statistic precision factor score of 5, and d) samples representative of the Spanish general population.
  
  
  RESULTS
  Four out 34 cohorts were selected. Mean gene frequencies (per 1,000) were: 104 (95% confidence interval [CI], 96-113) for PI*S and 17 (95% CI, 14-21) for PI*Z. These data indicated that it would exist in Spain 9,173,181 AATD subjects (95% CI, 9,167,966-9,178,398), with the following phenotypic distribution: 7,358,263 (95% CI, 6,696,222-8, 072,328) for PIMS; 1,222,041 (95% CI, 972,767-1,539,805) for PIMZ; 436,023 (95% CI, 369,057-514,244) for PISS; 144,827 (95% CI, 107,227-195,038) for PISZ; and 12,026 (95% CI, 7,788-18,493) for PIZZ. The global prevalence was 1 out of 4.4 individuals, with the following distribution: PIMS 1/5; PIMZ 1/33; PISS 1/92; PISZ 1/278; and PIZZ 1/3,344.
  
  
  CONCLUSIONS
  AATD is a frequent but underdiagnosed disease in Spain.
authors.affiliation: Sección de Neumología, Servicio de Medicina Interna, Hospital Valle del Nalón, Langreo, Principado de Asturias, Spain. ignacio.blanco@sespa.princast.es
authors.forename: Ignacio
authors.initials: I
authors.lastname: Blanco
authors.forename: Enrique
authors.initials: E
authors.lastname: Fernández-Bustillo
authors.forename: Frederick J
authors.initials: FJ
authors.lastname: de Serres
authors.forename: Daniel
authors.initials: D
authors.lastname: Alkassam
authors.forename: Carmen
authors.initials: C
authors.lastname: Rodríguez Menéndez
mesh_terms: D000328:Adult; D002648:Child; D016021:Epidemiologic Studies; D005787:Gene Frequency; D005838:Genotype; D006801:Humans; D010641:Phenotype; D015995:Prevalence; D013030:Spain / Q000453:epidemiology; D000515:alpha 1-Antitrypsin / Q000235:genetics*; D019896:alpha 1-Antitrypsin Deficiency / Q000453:epidemiology* / Q000235:genetics*
chemical_list: C043392:SERPINA1 protein, human; D000515:alpha 1-Antitrypsin