PubMed Health⌕ Search

Biomedical subjects

S K Cordovado

Publications and source records attributed to S K Cordovado.

3 recordsLinked to original sources
PubMed2005

High-resolution genotyping of HLA-DQA1 in the GoKinD study and identification of novel alleles HLA-DQA1*040102, HLA-DQA1*0402 and HLA-DQA1*0404.

In order to achieve high-resolution HLA-DQA1 genotyping, it is necessary to identify polymorphisms in exons 1, 2 and 3. We present a high-resolution sequence-based typing (SBT) strategy for genotyping exons 1, 2 and 3 of the polymorphic HLA-DQA1 locus. This method is an improvement upon previously presented methods, because it utilizes the minimum number of SSP-PCR assays to obtain clear DNA sequence in both the forward and reverse directions of all three exons. All known HLA-DQA1 alleles are resolved with the exception of HLA-DQA1*010101 and HLA-DQA1*010102 for which the distinguishing polymorphism is located in exon 4 and does not result in an amino acid change. This method has enabled our laboratory to identify three new HLA-DQA1 alleles - HLA-DQA1*040102, HLA- DQA1*0402 and HLA-DQA1*0404 - in the Genetics of Kidneys in Diabetes (GoKinD) study population. Additionally, we present single-allele amplification methods, which identify the coding sequences of HLA-DQA1 exons 1, 2, 3, intron 2 and 300 bp of the HLA-DQA1 promoter (QAP). This study, also describes the QAP for most of the known HLA-DQA1 alleles, three HLA-DQA2 promoter sequences and the intron 2 sequences for HLA-DQA1*040101, HLA-DQA1*040102, HLA-DQA1*0402 and HLA-DQA1*0404.

Alleles↗
PubMed2001

High-resolution sequence-based typing strategy for HLA-DQA1 using SSP-PCR and subsequent genotyping analysis with novel spreadsheet program.

We present a new sequence-based typing (SBT) strategy for the polymorphic HLA-DQA1 locus that is based on sequence-specific primer - polymerase chain reaction (SSP-PCR) amplification from genomic DNA. This method allows high-resolution genotyping in the second exon of the DQA1 gene. This gene presents a unique situation in which half of the known alleles contain an inframe three base pair deletion of codon 56. This deletion confounds direct SBT methodologies of heterozygous individuals containing both a deletion and nondeletion allele. The primary HLA haplotype associated with type 1 diabetes susceptibility is DR3/DR4. The DQA1 genotype for these two haplotypes are DQA1 *0501, a non-deletion allele and *0301, a deletion allele, thus creating a situation that cannot be resolved using a direct sequencing approach. Our group-specific SBT strategy isolates the deletion alleles from the nondeletion alleles, allowing them to be resolved by direct sequencing. Additionally, we present a novel spreadsheet program that accurately assigns the genotype of both homozygous and heterozygous persons.

Alleles↗
PubMed1999

Current activities at the Centers for Disease Control and Prevention's National Diabetes Laboratory.

In 1997, the Centers for Disease Control and Prevention established the National Diabetes Laboratory in order to help prevent and treat type 1 diabetes. This state-of-the-art laboratory collaborates with research scientists and key national and international organizations throughout the world to identify and study risk factors for type 1 diabetes by developing measurements for glycosylated proteins, developing and evaluating technology for measuring genetic risk factors for the disease, and working to standardize autoantibody measurements. Developing improved technologies for diagnosing and managing diabetes and developing reference materials for properly calibrating and standardizing blood glucose meters are also critical aspects of the laboratory's work. In addition, the laboratory provides quality storage for valuable collections of biologics and other materials and facilitates sharing of specimens, associated epidemiologic data, and test results. Working with our partners in diabetes research, we are improving the diagnosis, treatment, and prevention of type 1 diabetes.

Autoantibodies↗