Molecular analysis of immunized Jr(a-) or Lan- patients and validation of a high-throughput genotyping assay to screen blood donors for Jr(a-) and Lan- phenotypes.
BACKGROUND
Individuals with anti-Jr(a) or anti-Lan are ideally transfused with rare Jr(a-) or Lan- red blood cells. We characterized mutations in Dutch Jr(a-) and Lan- individuals and developed a high-throughput genotyping assay to detect Jr(a-) and Lan- donors.


METHODS
Six Jr(a-) and seven Lan- persons, who all made anti-Jr(a) or anti-Lan, were sequenced for ABCG2 or ABCB6 and the copy number of ABCG2 and ABCB6 was determined. A total of 3366 Caucasian, 621 black, and 333 Chinese donors were screened with a high-throughput screening assay targeting frequently occurring mutations causing the Jr(a-) or Lan- phenotype.


RESULTS
In the six tested Jr(a-) individuals previously described, c.376C > T, c.706C > T, and c.736C > T nonsense mutations in ABCG2 were detected. In the seven Lan- individuals 12 different mutations, of which 10 underlie the Lan- phenotype, were detected. No copy number variation was detected for ABCG2 and ABCB6. The high-throughput screening assay detected five Caucasian donors heterozygous for the c.706C > T or 736C > T mutation in ABCG2 and nine Caucasian donors heterozygous for the 574C > T mutation in ABCB6. No black or Chinese donors were found positive for a mutation.


CONCLUSIONS
We describe eight new mutations in ABCB6 of which seven, including three missense mutations, underlie the Lan- phenotype and determine that a complete gene deletion of ABCG2 or ABCB6 is not responsible for the Jr(a-) or Lan- phenotype, respectively. The extended heterogeneity of mutations causing the Jr(a-) or Lan- phenotype in most populations makes genetic screening for the Jr(a-) and Lan- phenotype inefficient in those populations.
Sanquin Research, Amsterdam and Landsteiner Laboratory, Academic Medical Centre, University of Amsterdam, Amsterdam, the Netherlands.
Lonneke
L
Haer-Wigman
Aïcha
A
Ait Soussan
Peter
P
Ligthart
Masja
M
de Haas
C Ellen
CE
van der Schoot
D000070997:ATP Binding Cassette Transporter, Subfamily G, Member 2; D018528:ATP-Binding Cassette Transporters / Q000235:genetics; D000483:Alleles; D044466:Asian People / Q000235:genetics; D001483:Base Sequence; D044383:Black People / Q000235:genetics; D001782:Blood Donors; D001789:Blood Group Antigens / Q000235:genetics* / Q000276:immunology*; D046148:Donor Selection; D060005:Genotyping Techniques; D057166:High-Throughput Screening Assays / Q000379:methods*; D006801:Humans; D007114:Immunization; D007519:Isoantigens / Q000235:genetics / Q000276:immunology*; D008969:Molecular Sequence Data; D009154:Mutation; D009363:Neoplasm Proteins / Q000235:genetics; D009426:Netherlands; D017422:Sequence Analysis, DNA / Q000379:methods*; D013019:South Africa; D044465:White People / Q000235:genetics
C107991:ABCB6 protein, human; C116614:ABCG2 protein, human; D000070997:ATP Binding Cassette Transporter, Subfamily G, Member 2; D018528:ATP-Binding Cassette Transporters; D001789:Blood Group Antigens; D007519:Isoantigens; C083301:LAN antigen; D009363:Neoplasm Proteins