Polymorphism scan for differences between transmitted and nontransmitted DRB1*030101 alleles outside of exon 2 for type 1 diabetes: the frequency of polymorphisms is similar.
DRB1*030101 is a major genetic risk factor for type 1 diabetes mellitus (T1DM) and is the only DRB1*03 allele usually seen in T1DM probands. Approximately 16% of parental DRB1*030101 alleles were not transmitted to T1DM probands in our Genetics of Kidneys and Diabetes study trio families. We performed a polymorphism screen to determine whether variations exist in DRB1*030101 alleles outside of exon 2 that may modify risk for developing T1DM. A combination of long-range and sequence-specific priming polymerase chain reaction was used to amplify a hemizygous template from both transmitted and nontransmitted parental DRB1*030101 chromosomes. Exon 2 DRB1*030101-specific and flanking DRB1-specific primers amplified the entire genomic locus as a 10.6-kb 5' fragment and a 5.3-kb 3' fragment, respectively. All exons and intron/exon borders of introns 1 and 2, all of introns 3-5, and flanking regulatory regions of 32 transmitted and 31 nontransmitted alleles (99% power to detect a 5% minimal allele frequency) were analyzed through fluorescent DNA sequencing. The only polymorphic sites detected, a previously described intron 2 complex dinucleotide repeat and an additional complex repeat approximately 1.8 kb downstream of exon 6, do not significantly differ between T1DM patients and controls in this small data set.
Division of Laboratory Sciences, Molecular Biology Branch, National Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, GA 30341, USA. crg0@cdc.gov
Christopher N
CN
Greene
Suzanne K
SK
Cordovado
Patricia W
PW
Mueller
D024509:3' Flanking Region / Q000235:genetics; D004247:DNA / Q000235:genetics / Q000302:isolation & purification; D003922:Diabetes Mellitus, Type 1 / Q000235:genetics*; D018900:Dinucleotide Repeats / Q000235:genetics; D005091:Exons / Q000235:genetics; D005787:Gene Frequency / Q000235:genetics; D006684:HLA-DR Antigens / Q000235:genetics*; D059811:HLA-DRB1 Chains; D006239:Haplotypes / Q000235:genetics; D006801:Humans; D040582:Inheritance Patterns / Q000235:genetics; D007438:Introns / Q000235:genetics; D018579:Patient Selection; D016133:Polymerase Chain Reaction / Q000379:methods; D011110:Polymorphism, Genetic / Q000235:genetics*; D011401:Promoter Regions, Genetic / Q000235:genetics; D017422:Sequence Analysis, DNA
D006684:HLA-DR Antigens; D059811:HLA-DRB1 Chains; D004247:DNA