STAR: a novel high-prevalence antigen in the Scianna blood group system.
BACKGROUND
More than 20 years ago, a proband was described whose red blood cells (RBCs) typed Sc:1,-2,3. His serum sample contained an immunoglobulin G alloantibody that reacted with all RBCs tested except his own, his brother's, and those with the Sc:-1,-2 phenotype. Cloning of the SC gene allowed determination of the molecular basis associated with this novel high-prevalence antigen.


METHODS
Samples from frozen storage were obtained from the proband, his serologically matched brother, and 15 serologically mismatched family members. DNA was extracted, and amplified products from all 11 SC (ERMAP) exons and their flanking regions of the proband were sequenced.


RESULTS
A single-nucleotide mutation was detected (139G>A) in Exon 3 that is predicted to encode a change of Amino Acid 47 from glutamic acid to lysine. The sequence analyses on samples from family members were as expected.


CONCLUSIONS
The absence of the high-prevalence antigen STAR detected by the proband's antibody is likely associated with lysine at Position 47 of the Sc glycoprotein. This amino acid change is located on the extracellular portion of HERMAP, 10 residues upstream from the polymorphism associated with Sc1 and Sc2 (Gly57Arg). STAR expands the Sc blood group system to five antigens and has been assigned the ISBT Number 013005 (SC5).
Hue-Roye
Kim
K
New York Blood Center, New York, New York 10021, USA.
Chaudhuri
Asok
A
Velliquette
Randall W
RW
Fetics
Susan
S
Thomas
Rebecca
R
Balk
Mary
M
Wagner
Franz F
FF
Flegel
William A
WA
Reid
Marion E
ME
D000954:Antigens, Surface / Q000235:genetics; D001324:Autoantigens; D001789:Blood Group Antigens / Q000235:genetics*; D000071797:Butyrophilins; D005190:Family; D005260:Female; D006801:Humans; D008297:Male; D008565:Membrane Proteins / Q000235:genetics; D010375:Pedigree; D017354:Point Mutation; D017411:Ribonucleoproteins, Small Nuclear / Q000235:genetics*; D055517:snRNP Core Proteins
D000954:Antigens, Surface; D001324:Autoantigens; D001789:Blood Group Antigens; D000071797:Butyrophilins; D008565:Membrane Proteins; D017411:Ribonucleoproteins, Small Nuclear; C472715:scianna antigens; D055517:snRNP Core Proteins