Screening for the SMIM1*64_80 del Allele in blood donors in a population from Southern Brazil.
OBJECTIVE
Serological screening for the Vel- phenotype is complex given the large individual variation in the levels of expression of the Vel antigen, and the polyclonal anti-human sera of immunised persons, when available, show heterogeneous reactivity levels. Studies of the SMIM1 gene have enabled the development of several molecular methodologies that will be crucially important for the screening of different populations, including Brazilians. To evaluate the deletion of 17 bp in the SMIM1 gene in a population from the south of Brazil, 448 unrelated blood donors from 7 regions comprising the haemotherapy network in the state of Santa Catarina were evaluated between August 2011 and March 2014.


METHODS
DNA samples from these donors were analysed employing a 5' nuclease real-time polymerase chain reaction (PCR) assay targeting the 17 bp deletion in the SMIM1 gene.


RESULTS
Among the 448 samples analysed, 10 (2·23%) harboured the 17 bp deletion of the gene SMIM1, and all were heterozygote for the SMIM1*64_80 del allele.


CONCLUSIONS
The allelic frequency found differed from those observed in other Caucasian populations. This difference can be explained by the ethnic make-up of each Caucasian population. The data obtained are important to characterise the correct phenotype of the donor as the serological assay results are not reliable due to variations in the expression intensity of the Vel antigen in heterozygote donors for the SMIM1*64_80 del allele. Moreover, the tool used in this study is of great value for identifying a donor Vel- phenotype and supplying a possible need for transfusion.
Graduate Program in Pharmacy, Federal University of Santa Catarina, UFSC, Florianópolis, Brazil.
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DC
Costa
Fundação Pró-Sangue/Hemocentro de São Paulo, Rua Dr. Enéas Carvalho Aguiar, São Paulo, Brazil.
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M
Dezan
Department of Clinical Analyses, Federal University of Santa Catarina, UFSC, Florianópolis, Brazil.
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T
Santos
Department of Clinical Analyses, Federal University of Santa Catarina, UFSC, Florianópolis, Brazil.
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AA
Schinaider
Immunohematology Laboratory, Santa Catarina Blood Bank, HEMOSC, Avenida Professor Othon Gama D'Eça, Florianópolis, Brazil.
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EJ
Schörner
Fundação Pró-Sangue/Hemocentro de São Paulo, Rua Dr. Enéas Carvalho Aguiar, São Paulo, Brazil.
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JE
Levi
Department of Clinical Analyses, Federal University of Santa Catarina, UFSC, Florianópolis, Brazil. maclau@ccs.ufsc.br.
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MC
Santos-Silva
D000483:Alleles; D001483:Base Sequence; D001782:Blood Donors; D001938:Brazil; D005260:Female; D006801:Humans; D008297:Male; D008565:Membrane Proteins / Q000235:genetics*; D012150:Polymorphism, Restriction Fragment Length; D060888:Real-Time Polymerase Chain Reaction; D017384:Sequence Deletion
D008565:Membrane Proteins; C584052:SMIM1 protein, human
blood groups; donors; genotyping; transfusion