Molecular genetic analysis for the Ae1 and A3 alleles.
BACKGROUND
In addition to the common ABO phenotypes, numerous phenotypes with a weak expression of the A or B antigens on RBCs have been found. This study describes the molecular genetic analysis of the Ael and the A3 phenotypes.


METHODS
The seven-exon regions of the ABO genes of Ael and A3B individuals were amplified by PCR and cloned, and the sequences of the exons and their adjacent splice sites were analyzed. Samples from 30 randomly selected A1 individuals were also assessed.


RESULTS
The A gene with wild-type coding sequence was demonstrated in the Ael propositus, but all the six unrelated Taiwanese people with the Ael or AelB phenotype were shown to possess an A allele with the G-->A mutation at the +5 position of intron 6 (IVS6+5G-->A). RT-PCR analysis showed that the complete A transcript structure was absent in the Ael RNA samples. The A3B individual possessed an A gene with an 838C-->T missense mutation.


CONCLUSIONS
The results suggest an association of the Ael*IVS6+5G-->A allele with the Ael phenotype in Taiwanese people. The mechanism defining how the Ael*IVS6+5G-->A allele leads to the Ael phenotype awaits elucidation.
Sun
Chien-Feng
CF
Department of Clinical Pathology, Chang-Gung Memorial Hospital, Taoyuan County, Taiwan.
Yu
Lung-Chih
LC
Chen
Ing-Ping
IP
Chou
Ding-Lun
DL
Twu
Yuh-Ching
YC
Wang
Wei-Ting
WT
Lin
Marie
M
D000017:ABO Blood-Group System / Q000235:genetics*; D000225:Adenine; D000483:Alleles; D001483:Base Sequence / Q000235:genetics; D003001:Cloning, Molecular; D003596:Cytosine; D006147:Guanine; D006801:Humans; D007438:Introns / Q000235:genetics; D008967:Molecular Biology / Q000379:methods; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D020125:Mutation, Missense / Q000235:genetics; D010641:Phenotype; D017354:Point Mutation / Q000235:genetics; D016133:Polymerase Chain Reaction; D012313:RNA / Q000032:analysis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013624:Taiwan; D013941:Thymine
D000017:ABO Blood-Group System; D006147:Guanine; D012313:RNA; D003596:Cytosine; D000225:Adenine; D013941:Thymine