title: Impact of genetics in childhood asthma.
abstract: OBJECTIVE
  To present the most important and recent results of studies on asthma genetics. These data may help general physicians understand the impact of genetics on this complex disorder and how genes and polymorphisms influence asthma and atopy.
  
  
  METHODS
  Data were collected from MEDLINE. Genetic association studies were selected from the Genetic Association Database, which is an archive of human genetic association studies of complex diseases and disorders organized by the National Institutes of Health.
  
  
  RESULTS
  Considering the data from several important twin studies on asthma genetics, heritability, which measures the contribution of genetic factors to the variance of asthma, may be estimated in 0.48-0.79. A huge number of genetic association studies have been trying to identify asthma susceptibility genes. The most replicated results in the genetic association studies involve the following five regions of the human genome: 5q31-32, 6p21, 11q12-13, 16p11-12, and 20p13. Only recently a new asthma susceptibility gene (ORMDL3) has been identified by a whole genome association study, considered to be a major determinant for childhood asthma.
  
  
  CONCLUSIONS
  Genetic contribution to asthma may be estimated ranging from 48 to 79%. Several loci seem to influence asthma susceptibility. Genes located on chromosome 5q (ADRB2, IL13 and IL4) and the recently identified ORMDL3, on chromosome 17, seem to be determinants of childhood asthma. Diagnostics and pharmacogenetics may be the first clinical implication of extensive studies on asthma genetics.
authors.affiliation: Instituto de Pesquisas Biomédicas, Hospital São Lucas, Pontifícia Universidade Católica do Rio Grande do Sul (PUCRS), Porto Alegre, RS, Brazil.
authors.forename: Leonardo A
authors.initials: LA
authors.lastname: Pinto
authors.forename: Renato T
authors.initials: RT
authors.lastname: Stein
authors.forename: Michael
authors.initials: M
authors.lastname: Kabesch
mesh_terms: D001249:Asthma / Q000235:genetics*; D002648:Child; D002877:Chromosomes, Human; D004200:Diseases in Twins / Q000235:genetics; D020022:Genetic Predisposition to Disease; D015894:Genome, Human; D055106:Genome-Wide Association Study; D006801:Humans; D010597:Pharmacogenetics; D018433:Twin Studies as Topic; D014481:United States