An AQP1 allele associated with co (a-b-) phenotype
Vege, S.; Nance, S.; Kavitsky, D.; Li, X.; Horn, T.; Meny, G.; Westhoff, C.M.
Immunohematology 29(1): 1-4
2013
ISSN/ISBN: 0894-203X PMID: 24046915 Document Number: 667030
The Colton (CO) blood group system consists of four antigens, Co(a), Co(b), Co3, and Co4, located on aquaporin-1 (AQP1), with Co(a) highly prevalent in all populations (99.8%). The Colton null phenotype, Co(a-b-), is very rare, and individuals with this phenotype lack the high-prevalence antigen Co3. To date, only six Co(a-b-) probands have been reported and four silencing alleles characterized. We identified an AQP1-null allele in a white woman with anti-Co3 caused by deletion of a G at nucleotide 601 (nt601delG) that results in a frameshift and premature termination (Val201Stop). Available family members were tested for the allele. Although anti-Co3 has been associated with mild to severe hemolytic disease of the fetus and newborn, the antibody was not clinically significant as evidenced by a low titer and delivery of asymptomatic newborns with moderate to weakly positive direct antiglobulin tests for all four pregnancies.