title: Tests and estimates (transmission disequilibrium test) for allelic association of CCR5delta32 with asthma in high-risk families.
abstract: OBJECTIVE
  To examine the possible associations between CCR5delta32 and asthma and related phenotypes in high-risk families.
  
  
  METHODS
  A total of 154 families (453 individuals), with at least two affected children with physician-diagnosed asthma (PDA) and atopy defined as one or more skin prick test to common inhaled allergen (SPT wheal > or = 3 mm), were studied. Samples were genotyped using PCR assay and tested for possible associations by TDT and PDT and case control analyses.
  
  
  RESULTS
  Overall allelic frequency for CCR5delta32 was 26.1%, and both TDT and PDT demonstrated similar nonsignificant associations (p=0.123) and (p=0.088). Analysis by the clinical categories of non atopic and atopic asthma and presence or absence of atopy without asthma failed to identify any significant associations. However there were strong associations of the mutant allele with the phenotypes of negative SPT, PC 20 less than 8 mg/ml, baseline FEV1 greater than the population median (83.5% predicted) and serum IgE less than 100 IU/l for child probands but only for negative SPT in unrelated parents.
  
  
  CONCLUSIONS
  Non-significant association was seen with family based association tests (FBATs). The strong associations with the asthma related phenotypes in child probands support previous observations that CCR5 is in linkage disequilibrium with CCR2 or CCR3.
authors.affiliation: Department of Child Health, Royal Aberdeen Children's Hospital, University of Aberdeen, Medical School, Westburn Road, Aberdeen, Scotland, United Kingdom.
authors.forename: Saleh Abdullah
authors.initials: SA
authors.lastname: Al-Abdulhadi
authors.forename: M W
authors.initials: MW
authors.lastname: Al-Rabia
mesh_terms: D000293:Adolescent; D000328:Adult; D000483:Alleles; D000485:Allergens / Q000276:immunology; D001249:Asthma / Q000235:genetics* / Q000276:immunology / Q000503:physiopathology; D016022:Case-Control Studies; D002648:Child; D005260:Female; D005541:Forced Expiratory Volume; D005787:Gene Frequency; D020022:Genetic Predisposition to Disease; D005838:Genotype; D006801:Humans; D006969:Hypersensitivity, Immediate / Q000235:genetics* / Q000276:immunology; D015810:Linkage Disequilibrium; D008297:Male; D008875:Middle Aged; D009154:Mutation; D010641:Phenotype; D010865:Pilot Projects; D020641:Polymorphism, Single Nucleotide; D054390:Receptors, CCR2 / Q000235:genetics; D054397:Receptors, CCR3 / Q000235:genetics; D019713:Receptors, CCR5 / Q000235:genetics* / Q000378:metabolism; D012129:Respiratory Function Tests; D012882:Skin Tests; D055815:Young Adult
chemical_list: D000485:Allergens; C515334:CCR2 protein, human; C515350:CCR3 protein, human; D054390:Receptors, CCR2; D054397:Receptors, CCR3; D019713:Receptors, CCR5