title: Identification of the Rare, Four Repeat Allele of IL-4 Intron-3 VNTR Polymorphism in Indian Populations.
abstract: BACKGROUND
  Cytokines are cell signaling molecules which upon release by cells facilitate the recruitment of immune-modulatory cells towards the sites of inflammation. Genetic variations in cytokine genes are shown to regulate their production and affect the risk of infectious as well as autoimmune diseases. Intron-3 of interleukin-4 gene (IL-4) harbors 70-bp variable number of tandem repeats (VNTR) that may alter the expression level of IL-4 gene.
  
  
  OBJECTIVE
  To determine the distribution of IL-4 70-bp VNTR polymorphism in seven genetically heterogeneous populations of Chhattisgarh, India and their comparison with the finding of other Indian and world populations.
  
  
  METHODS
  A total of 371 healthy unrelated individuals from 5 caste and 2 tribal populations were included in the present study. The IL-4 70-bp VNTR genotyping was carried out using PCR and electrophoresis.
  
  
  RESULTS
  Overall, 3 alleles of IL-4 70-bp VNTR (a2, a3 and a4) were detected. The results demonstrated the variability of the IL-4 70-bp VNTR polymorphism in Chhattisgarh populations. Allele a3 was the most common allele at the 70-bp VNTR locus in all populations followed by a2 allele. This study reports the presence four repeat allele a4 at a low frequency in the majority of the Chhattisgarh populations studied. Further, the frequency of the minor allele (a2) in Chhattisgarh populations showed similarity with the frequencies of European populations but not with the East Asian populations where the a2 allele is a major allele.
  
  
  CONCLUSIONS
  Our study provides a baseline for future research into the role of the IL-4 locus in diseases linked to inflammation in Indian populations.
authors.affiliation: Sickle Cell Institute Chhattisgarh, Raipur, Chhattisgarh, India, E mail: henu.verma@yahoo.com.
authors.forename: Henu Kumar
authors.initials: HK
authors.lastname: Verma
authors.forename: Aditya Nath
authors.initials: AN
authors.lastname: Jha
authors.forename: Prafulla Kumar
authors.initials: PK
authors.lastname: Khodiar
authors.forename: Pradeep Kumar
authors.initials: PK
authors.lastname: Patra
authors.forename: Lakkakula Venkata Kameswara Subrahmanya
authors.initials: LV
authors.lastname: Bhaskar
mesh_terms: D000483:Alleles; D001327:Autoimmune Diseases / Q000235:genetics*; D004252:DNA Mutational Analysis; D005006:Ethnicity; D005787:Gene Frequency; D020022:Genetic Predisposition to Disease; D005838:Genotype; D006801:Humans; D007194:India; D007239:Infections / Q000235:genetics*; D015847:Interleukin-4 / Q000235:genetics*; D007438:Introns / Q000235:genetics*; D018598:Minisatellite Repeats / Q000235:genetics*; D011110:Polymorphism, Genetic; D012306:Risk
chemical_list: D015847:Interleukin-4