Presence of the RHD pseudogene and the hybrid RHD-CE-Ds gene in Brazilians with the D-negative phenotype

Autor(es)

A. Rodrigues ^[1] ; M. Rios ^[2] ; J. Pellegrino Jr. ^[3] ; F.F. Costa ^[4] ; L. Castilho ^[5]

Afiliação do(s) autor(es)

^[1] Universidade Estadual de Campinas. Hemocentro - Brasil

^[2] New York Blood Center - Estados Unidos

^[3] Universidade Estadual de Campinas. Hemocentro - Brasil

^[4] Universidade Estadual de Campinas. Hemocentro - Brasil

^[5] Universidade Estadual de Campinas. Hemocentro - Brasil

• Tipo de documento: Artigo Científico
• Fonte: Brazilian Journal of Medical and Biological Research; v. 35, n. 7, p. 767-773, 2002-07-00.

Resumo

The molecular basis for RHD pseudogene or RHDpsi is a 37-bp insertion in exon 4 of RHD. This insertion, found in two-thirds of D-negative Africans, appears to introduce a stop codon at position 210. The hybrid RHD-CE-Ds, where the 3' end of exon 3 and exons 4 to 8 are derived from RHCE, is associated with the VS+V- phenotype, and leads to a D-negative phenotype in people of African origin. We determined whether Brazilian blood donors of heterogeneous ethnic origin had RHDpsi and RHD-CE-Ds. DNA from 206 blood donors were tested for RHDpsi by a multiplex PCR that detects RHD, RHDpsi and the C and c alleles of RHCE. The RHD genotype was determined by comparison of size of amplified products associated with the RHD gene in both intron 4 and exon 10/3'-UTR. VS was determined by amplification of exon 5 of RHCE, and sequencing of PCR products was used to analyze C733G (Leu245Val). Twenty-two (11%) of the 206 D-negative Brazilians studied had the RHDpsi, 5 (2%) had the RHD-CE-Ds hybrid gene associated with the VS+V- phenotype, and 179 (87%) entirely lacked RHD. As expected, RHD was deleted in all the 50 individuals of Caucasian descent. Among the 156 individuals of African descent, 22 (14%) had inactive RHD and 3% had the RHD-CE-Ds hybrid gene. These data confirm that the inclusion of two different multiplex PCR for RHD is essential to test the D-negative Brazilian population in order to avoid false-positive typing of polytransfused patients and fetuses. (AU)

• Processo FAPESP: 99/03620-0 - Biologia molecular do sistema rh e sua aplicacao em medicina transfuncional e materno-fetal.
• Beneficiário: Lilian Maria de Castilho
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 00/03510-0 - Caracterizacao molecular das variantes do sistema rh e sua aplicacao em medicina transfusional e materno-fetal.
• Beneficiário: Artemis Socorro Do Nascimento Rodrigues
• Modalidade de apoio: Bolsas no Brasil - Mestrado