Related Experiment Video

Updated: Aug 18, 2026

Generation of High Quality Chromatin Immunoprecipitation DNA Template for High-throughput Sequencing (ChIP-seq)
09:52

Generation of High Quality Chromatin Immunoprecipitation DNA Template for High-throughput Sequencing (ChIP-seq)

Published on: April 19, 2013

C4 Chido 3 and 6 distinguish two diabetogenic haplotypes: HLA-B49, SC01,DR4,DQw8 and B8,SC01,DR3,DQw2

O G Segurado1, C M Giles, P Iglesias-Casarrubios

  • 1Hospital 12 de Octubre, Madrid, Spain.

Immunobiology
|September 1, 1991
PubMed

Insights

A novel HLA-B49,DR4,DQw8 haplotype associated with insulin-dependent diabetes mellitus (IDDM) in Spain carries the SC01 complotype. This finding highlights the role of deleted class III region genes in IDDM susceptibility.

Area of Science:

  • Immunogenetics
  • Human Leukocyte Antigen (HLA) complex
  • Complement system genetics

Background:

  • The SC01 complotype, comprising specific HLA complement allotypes (BFS, C2C, C4AQ0 deleted, C4B1), is typically found on the HLA-B8,DR3,DQw2 haplotype associated with diabetes.
  • Insulin-dependent diabetes mellitus (IDDM) susceptibility is linked to specific HLA haplotypes, particularly in certain populations.

Purpose of the Study:

  • To investigate a novel HLA-B49,DR4,DQw8 haplotype found in Spanish IDDM patients.
  • To characterize the genetic makeup of this novel haplotype and compare it to known IDDM-associated haplotypes.
  • To determine the association of extended haplotypes with deleted class III region genes and IDDM susceptibility in Mediterranean populations.

Main Methods:

  • Family studies utilizing C4 antigenic determinants (Rodgers/Chido) and C4d nucleotide sequences.
  • Serological and DNA-level analysis of Chido determinants.
  • Restriction fragment length polymorphism (RFLP) analysis of BF, C2, steroid 21-hydroxylase, and C4 genes.
  • Comparison of novel haplotype with the common HLA-B8,DR3 haplotype.

Main Results:

  • A novel, low-frequency HLA-B49,DR4,DQw8 haplotype associated with Spanish IDDM was identified, carrying the SC01 complotype with Chido -3, -6.
  • This novel haplotype is genetically distinct from the common HLA-B8,DR3 haplotype (Chido 3,6) and not a result of recent recombination.
  • The HLA-B49,SC01,DR4 haplotype is the first DR4-bearing IDDM-susceptible haplotype with a deleted C4 gene and the only DR4-bearing haplotype in the Spanish population.
  • Extended haplotypes with deleted class III region genes are more frequently associated with IDDM susceptibility in Spanish and other Mediterranean populations.

Conclusions:

  • The HLA-B49,DR4,DQw8 haplotype represents a distinct genetic factor contributing to IDDM susceptibility in the Spanish population.
  • Chido typing is crucial for differentiating SC01 complotypes on different extended haplotypes.
  • Deleted genes within the class III region of the HLA complex are significant risk factors for IDDM, particularly in Mediterranean populations.

More Related Videos

High-resolution Melting PCR for Complement Receptor 1 Length Polymorphism Genotyping: An Innovative Tool for Alzheimer's Disease Gene Susceptibility Assessment07:26

High-resolution Melting PCR for Complement Receptor 1 Length Polymorphism Genotyping: An Innovative Tool for Alzheimer's Disease Gene Susceptibility Assessment

Published on: July 18, 2017

Personalized Peptide Arrays for Detection of HLA Alloantibodies in Organ Transplantation08:07

Personalized Peptide Arrays for Detection of HLA Alloantibodies in Organ Transplantation

Published on: September 6, 2017

Related Concept Videos

Genetic Lingo01:11

Genetic Lingo

Overview
Multiple Allele Traits01:49

Multiple Allele Traits

The Concept of Multiple Allelism
Exon Recombination02:32

Exon Recombination

The evolution of new genes is critical for speciation. Exon recombination, also known as exon shuffling or domain shuffling, is an important means of new gene formation. It is observed across vertebrates, invertebrates, and in some plants such as potatoes and sunflowers. During exon recombination, exons from the same or different genes recombine and produce new exon-intron combinations, which might evolve into new genes. 
Exon shuffling follows “splice frame rules.” Each exon has three reading...
Genome-wide Association Studies-GWAS01:11

Genome-wide Association Studies-GWAS

Genome-wide association studies or GWAS are used to identify whether common SNPs are associated with certain diseases. Suppose specific SNPs are more frequently observed in individuals with a particular disease than those without the disease. In that case, those SNPs are said to be associated with the disease. Chi-square analysis is performed to check the probability of the allele likely to be associated with the disease.
GWAS does not require the identification of the target gene involved in...