Evans antigen: a new hybrid structure occurring on background of D.. and D-- Rh complexes.
OBJECTIVE
Previously, the Evans antigen (RH37) of the Rh blood group system was shown to be specified by a novel CE-D-CE hybrid gene. We studied further the heterogeneity of Evans and report here its new molecular type resulting from a novel intraexon fusion event on the background of D. and D-- complexes.


METHODS
A white family with 2 Evans+ and 2 Evans- members was analyzed by serological methods and molecular techniques.


RESULTS
The Evans+ proband (JD) typed D+C-c-E-e- and showed a partial loss of RHCE but an increased dose of RHD on DNA blots. On sequencing of Rh cDNAs, a normal D and 3 hybrid transcripts were detected. The D-CE hybrid is characterized by a single breakpoint located in exon 6. The CE-D hybrid derived its exon 1 (or 1 and 2) from RHCE and exons 2-10 (or 3-10) from RHD. The CE-D-CE hybrid had its internal exons 2-7 (or 3-7) from RHD. Family studies showed that the D-CE and CE-D hybrids were linked and cotransmitted from JD to his son, whereas RHD and CE-D-CE hybrid were transmitted from JD to his daughter.


CONCLUSIONS
In this family, Evans is specified by the novel D-CE intraexon fusion gene which occurs in cis to CE-D and trans to CE-D-CE interexon fusion genes. The observed large duplication of RHD reflects a convergent mosaicism underlying the enhancement of D and ablation of CcEe antigens.
Cheng
G J
GJ
Laboratories of Biochemistry and Molecular Genetics, Lindsley F. Kimball Research Institue, New York Blood Center, New York, NY 10021, USA.
Chen
Y
Y
Reid
M E
ME
Huang
C H
CH
D000595:Amino Acid Sequence; D000941:Antigens / Q000097:blood* / Q000235:genetics*; D019677:Artificial Gene Fusion; D015415:Biomarkers / Q000097:blood; D002874:Chromosome Mapping; D016172:DNA Fingerprinting; D005091:Exons / Q000235:genetics; D005192:Family Health; D005260:Female; D008040:Genetic Linkage; D005838:Genotype; D006384:Hemagglutination / Q000235:genetics; D006801:Humans; D008297:Male; D010375:Pedigree; D010641:Phenotype; D012150:Polymorphism, Restriction Fragment Length; D012204:Rh-Hr Blood-Group System / Q000235:genetics* / Q000276:immunology; D016415:Sequence Alignment; D014158:Transcription, Genetic; D044465:White People / Q000235:genetics
D000941:Antigens; D015415:Biomarkers; D012204:Rh-Hr Blood-Group System