title: Analysis of compound heterozygous CYP2C19 genotypes to determine cis and trans configurations.
abstract: BACKGROUND
  Through allele specific PCR we studied 220 CYP2C19 compound heterozygous samples, of unknown ethnicity, to determine the haplotype for each of the variations within a sample.
  
  
  METHODS
  The genotypes assessed were: 180 *2 and *17 samples (100% in trans); 20 *2 and *11 samples (100% in cis); ten *4 and *17 samples (50% of the samples were *1/*4B and 50% *4A/*17); six *2, *11 and *17 samples (100% showed *2 and *11 in cis, and *17 in trans); two *2, *4 and *17 samples (100% *4B with *2 in trans); one sample with *17 and *34 (these were in trans); and one sample that contained *2, *17, c.463G>T (p.E155X; *17 and c.463G>T were in cis, with *2 in trans).
  
  
  CONCLUSIONS
  In our study, we observed a different frequency for the *4B allele (when a sample contains both *4 and *17); and identified *17 occurring in cis with a novel nonsense allele. Accurately assessing a patient's genotype, including assignment of a haplotype, can be important when making a phenotype prediction.
authors.affiliation: Personalized Genomics Laboratory, Department of Laboratory Medicine & Pathology, Mayo Clinic & Mayo Medical School, 200 First St SW, Rochester, MN 55905, USA.
authors.forename: Jennifer M
authors.initials: JM
authors.lastname: Skierka
authors.forename: John Logan
authors.initials: JL
authors.lastname: Black
mesh_terms: D000483:Alleles; D065731:Cytochrome P-450 CYP2C19 / Q000737:chemistry* / Q000235:genetics*; D005787:Gene Frequency; D006239:Haplotypes; D006579:Heterozygote; D006801:Humans; D020641:Polymorphism, Single Nucleotide; D011487:Protein Conformation
chemical_list: C045793:CYP2C19 protein, human; D065731:Cytochrome P-450 CYP2C19
keywords: CYP2C19; CYP2C19*11; CYP2C19*17; CYP2C19*2; CYP2C19*4; cis; cytochrome P450 2C19; haplotype; trans