[RH hybrid box identification in subjects with Rh negative phenotype from Mexico's Valley].

Background: The prevalence of the RhD and RhCE gene alleles is related to the ethnic mixture. The aim of this report is to describe the predominant molecular mechanisms in RhD negative subjects residents from Mexico's valley according to the phenotype of RhCE.

Methods: Blood samples from RhD negative women and men were studied. The RhD/RhCE phenotype was identified by hemagglutination and Rh hybrid box by PCR-FRLP with PstI.

Results: 216 subjects were included. The RhD phenotypes were ccdee in 179 cases (82.8%), Ccdee in 15 cases (11.6%), ccdEe in seven (3.2%), CcdEe in four (1.9%), and CcdEE in a single subject (0.5%). In five cases, RhD hybrid box was not amplified (2.3%), 21 cases were hemizygotes (9.7%), and 188 cases homozygotes (87%), for RhD hybrid box. The homozygote condition was more frequent in those individuals with phenotype ccdee (87%). The allelic frequency of RhD hybrid box was 0.928. The frequency of Rhcc haplotype was higher in those subjects homozygotes for RhD hybrid box (chi2 = 4.658, p < 0.05).

Conclusions: In this population, RhD gene deletion is the main molecular mechanism to generate to RhD negative condition and this depends on the European mixture.