Scianna antigens including Rd are expressed by ERMAP.
The Scianna blood group encompasses the high-frequency antigens Sc1 and Sc3 and the low-frequency antigen Sc2. Another low-frequency antigen Rd (Radin) was suggested to belong to the Scianna blood group. The molecular basis of the Scianna blood group was unknown. The erythrocyte membrane-associated protein (ERMAP) shared the genomic location, protein product size, and localization to the red blood cell (RBC) membrane surface with Scianna. The ERMAP gene was sequenced in probands with known Scianna and Radin phenotypes. In a Sc:-1,-2 proband, only an ERMAP allele with a 2-bp deletion in exon 3 causing a frameshift could be detected. A Sc:-1,2 proband was homozygous for the ERMAP(Gly57Arg) allele. An Rd(+) proband was heterozygous for the ERMAP(Pro60Ala) allele. Polymerase chain reaction with sequence-specific priming (PCR-SSP) systems was developed to detect the Sc2 and Rd alleles of the ERMAP gene. The 2 alleles occurred with about 1% and less than 1% frequency in the population, which was compatible with the frequency of the Sc2 and Rd antigens known in whites. Two Sc2(+) and one Rd(+) samples that were found by genotyping were confirmed by serology. The antigens of the Scianna blood group include Rd and are expressed by the human ERMAP protein. Sc2 is caused by an ERMAP(Gly57Arg) allele and Rd by an ERMAP(Pro60Ala) allele. Scianna is the last of the previously characterized protein-based blood group systems whose molecular basis was discerned. Hence, the phenotype prediction by genotyping became possible for all human blood group systems encoded by proteins.
Wagner
Franz F
FF
Department of Transfusion Medicine, University of Ulm, DRK (German Red Cross)-Blood Donation Service Baden-Württemberg-Hessen, Institute Ulm, Germany.
Poole
Joyce
J
Flegel
Willy A
WA
D000954:Antigens, Surface / Q000235:genetics; D001324:Autoantigens; D001789:Blood Group Antigens / Q000235:genetics*; D000071797:Butyrophilins; D016368:Frameshift Mutation; D008040:Genetic Linkage; D006801:Humans; D007519:Isoantigens / Q000235:genetics*; D008565:Membrane Proteins / Q000235:genetics* / Q000276:immunology; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000235:genetics*; D016133:Polymerase Chain Reaction; D020641:Polymorphism, Single Nucleotide; D017411:Ribonucleoproteins, Small Nuclear / Q000235:genetics*; D017422:Sequence Analysis, DNA; D017384:Sequence Deletion; D014157:Transcription Factors; D035602:Transcriptional Elongation Factors; D055517:snRNP Core Proteins
D000954:Antigens, Surface; D001324:Autoantigens; D001789:Blood Group Antigens; D000071797:Butyrophilins; D007519:Isoantigens; D008565:Membrane Proteins; D009687:Nuclear Proteins; D017411:Ribonucleoproteins, Small Nuclear; D014157:Transcription Factors; D035602:Transcriptional Elongation Factors; C118437:negative elongation factor; C472715:scianna antigens; D055517:snRNP Core Proteins