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SMIM1 polymorphisms in a donor population from southeast Brazil and their correlation with VEL expression.

Authors :
Arnoni CP
De Paula Vendrame TA
Muniz JG
Gazito D
De Medeiros Person RD
Pereira Cortez AJ
Latini FRM
Castilho L
Source :
Blood transfusion = Trasfusione del sangue [Blood Transfus] 2019 Jan; Vol. 17 (1), pp. 60-65. Date of Electronic Publication: 2018 Jan 11.
Publication Year :
2019

Abstract

Background: Vel is a high frequency blood group antigen and its alloantibody is involved in haemolytic transfusion reactions. After elucidation of the molecular basis of the Vel-negative phenotype defined by a 17-base pair deletion in SMIM1, genotyping has been the technique of choice to identify the Vel-negative phenotype, and molecular investigations have contributed to explain Vel expression variability. The present study was aimed at screening for Vel negative blood donors and characterising the genetic changes found in Brazilian donors with altered Vel expression.<br />Materials and Methods: Molecular screening for the SMIM1*64_80del allele was performed in 1,595 blood donor samples using a SNaPshot protocol previously standardised in our laboratory. Four hundred donor samples were also submitted to serological screening using a polyclonal anti-Vel from our inventory. Samples with variability in antigen strength were selected for SMIM1 sequencing.<br />Results: No homozygous SMIM1*64_80del allele was found and the SMIM1*64_80del allele frequency was 1.01%. Different patterns of reactivity were observed in serological testing varying from negative to 3+. Through sequencing analysis we highlighted two polymorphisms: rs1175550 and rs6673829. The minor G allele of rs1175550 was found in 16/20 samples reacting 3+, while the major A allele was found in 21/23 samples reacting 2+. Regarding rs6673829, the minor A allele was present in 14/23 and 3/20 samples reacting 2+ and 3+ respectively.<br />Discussion: We included molecular VEL screening in a previously standardised SNaPshot protocol, which besides enabling detection of Vel-negative donors, also searches for eight other rare blood types. Additionally, the present study demonstrated that although the SMIM1*64_80del allele is responsible for some variation of Vel phenotype in this donor population, Vel expression is also controlled by molecular changes in SMIM1 intron 2.

Details

Language :
English
ISSN :
2385-2070
Volume :
17
Issue :
1
Database :
MEDLINE
Journal :
Blood transfusion = Trasfusione del sangue
Publication Type :
Academic Journal
Accession number :
29517970
Full Text :
https://doi.org/10.2450/2018.0192-17