Establishing RHD zygosity in India: a step into the future of foetal and neonatal haemolytic disease prevention

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.

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.

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.

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.

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.