title: Establishing RHD zygosity in India: a step into the future of foetal and neonatal haemolytic disease prevention.
abstract: BACKGROUND
  Determination of RHD zygosity is important for the prevention of haemolytic disease of foetus and neonate. There is no data from India regarding the prevalence of RHD genotypes.
  
  
  OBJECTIVE
  We conducted this study to investigate RHD zygosity in phenotypically RhD positive (RhD+) Indians. We have also investigated the utility and concordance of two different genotyping techniques.
  
  
  METHODS
  Hundred serologically RhD+ Indians were genotyped at the RHD gene using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and polymerase chain reaction-sequence-specific primer (PCR-SSP) techniques.
  
  
  RESULTS
  Of the 100 RhD+ individuals, 26 (25%) were D heterozygous by both methods and 74 (71·2%) were D homozygous. There was no discordance in the results from the two techniques.
  
  
  CONCLUSIONS
  At least 25% of RhD+ Indians are heterozygous at the RHD gene. Both the genotyping techniques were equally robust and their complete concordance indicates RHD deletion as the main mechanism underlying RhD negativity in Indians.
authors.affiliation: Department of Medical Genetics, Sanjay Gandhi Post Graduate Institute of Medical Sciences, Lucknow, India. saritasgpgi@gmail.com
authors.forename: S
authors.initials: S
authors.lastname: Aggarwal
authors.forename: V
authors.initials: V
authors.lastname: Arya
authors.forename: S
authors.initials: S
authors.lastname: Agarwal
mesh_terms: D000745:Anemia, Hemolytic, Congenital / Q000517:prevention & control*; D005838:Genotype; D006579:Heterozygote; D006801:Humans; D007194:India; D007231:Infant, Newborn; D016133:Polymerase Chain Reaction / Q000379:methods; D012150:Polymorphism, Restriction Fragment Length; D015995:Prevalence; D012204:Rh-Hr Blood-Group System / Q000235:genetics*
chemical_list: D012204:Rh-Hr Blood-Group System; C026410:Rho(D) antigen