title: A cluster of highly polymorphic dinucleotide repeats in intron 17b of the cystic fibrosis transmembrane conductance regulator (CFTR) gene.
abstract: A cluster of highly polymorphic dinucleotide repeats has been detected in intron 17b of the CFTR gene, 200 bp downstream from the preceding exon. At least 24 alleles, with sizes ranging from 7 to 56 units of a TA repeat, have been identified in a panel of 92 unrelated carriers of cystic fibrosis (CF). The common ones are those with 7, 30, and 31 dinucleotide units, with frequencies of .22, .19, and .12, respectively, among the non-CF chromosomes. Mendelian, codominant segregation of the alleles has been demonstrated in family studies, as expected. A less polymorphic dinucleotide (CA repeat) cluster has also been detected in a region 167 bp downstream from the TA repeat. The length of the CA repeat cluster varies from 11 to 17 dinucleotide units, and it appears to have an inverse relationship to that of the TA repeats. These dinucleotide repeats should be useful in genetic linkage studies, in counseling for CF families with unknown mutations, and in tracing the origins of the various mutant CF alleles.
authors.affiliation: Department of Genetics, Hospital for Sick Children, Toronto, Ontario, Canada.
authors.forename: J
authors.initials: J
authors.lastname: Zielenski
authors.forename: D
authors.initials: D
authors.lastname: Markiewicz
authors.forename: F
authors.initials: F
authors.lastname: Rininsland
authors.forename: J
authors.initials: J
authors.lastname: Rommens
authors.forename: L C
authors.initials: LC
authors.lastname: Tsui
mesh_terms: D000227:Adenine Nucleotides; D001483:Base Sequence; D003550:Cystic Fibrosis / Q000235:genetics*; D019005:Cystic Fibrosis Transmembrane Conductance Regulator; D003597:Cytosine Nucleotides; D005809:Genes, Regulator; D008040:Genetic Linkage; D006801:Humans; D007438:Introns; D008565:Membrane Proteins / Q000235:genetics*; D008969:Molecular Sequence Data; D009154:Mutation; D011110:Polymorphism, Genetic; D012091:Repetitive Sequences, Nucleic Acid; D013942:Thymine Nucleotides
chemical_list: D000227:Adenine Nucleotides; C505032:CFTR protein, human; D003597:Cytosine Nucleotides; D008565:Membrane Proteins; D013942:Thymine Nucleotides; D019005:Cystic Fibrosis Transmembrane Conductance Regulator