Cis-AB and B(A) alleles encode an ABO enzyme with dual A and B glycosyltransferase activity. Although globally rare, the cis-AB phenotype is found relatively often in Korean, Japanese, and Chinese populations. Cases of the B(A) allele have been reported mostly in the Chinese population. Forward typing performed in a Cambodian woman with an ABO discrepancy demonstrated a strong reaction with anti-A and anti-B reagents, while there was no reaction with lectin anti-A 1. The anti-A 1 antibody was detected in reverse typing. Through ABO gene sequence analyses of exons 6 and 7, one of the alleles was identified as ABO*B.01. In contrast, the other allele harboring a c.803G＞C substitution was either ABO*cisAB.05 or ABO*BA.06 allele. The ABO*cisAB.05 and ABO*BA.06 alleles remain indistinguishable despite routine serological testing and ABO genotyping. To the best of the author’s knowledge, this is the first case report of these variants discovered in a Cambodian individual residing in Korea.

Weak D and partial D result in quantitative and qualitative changes in RhD protein expression respectively. It is difficult to discriminate weak D from partial D by serological tests alone. RHD genotyping is a useful method that complements serological results. A 64-year-old woman visited our hospital for microvascular decompression surgery. Her blood type was O, D negative by manual tube test and as per auto analyzer results (QWALYS-3 system; DIAGAST, France). Weak D and partial D tests were performed by using two different monoclonal anti-D reagents (Bioscot; Merck Millipore, UK; Bioclone; Ortho Clinical Diagnostics, USA) and a panel of nine monoclonal antibodies, including anti-D IgM and IgG (D-Screen; DIAGAST, France). However, these serological tests could not confirm the subtype of partial D. Therefore, sequencing of RHD exon 1 to 10 was additionally performed for the patient and the case was revealed to be partial DVI type 3.

Cis-AB and B(A) alleles encode an ABO enzyme with dual A and B glycosyltransferase activity. Although globally rare, the cis-AB phenotype is found relatively often in Korean, Japanese, and Chinese populations. Cases of the B(A) allele have been reported mostly in the Chinese population. Forward typing performed in a Cambodian woman with an ABO discrepancy demonstrated a strong reaction with anti-A and anti-B reagents, while there was no reaction with lectin anti-A 1. The anti-A 1 antibody was detected in reverse typing. Through ABO gene sequence analyses of exons 6 and 7, one of the alleles was identified as ABO*B.01. In contrast, the other allele harboring a c.803G＞C substitution was either ABO*cisAB.05 or ABO*BA.06 allele. The ABO*cisAB.05 and ABO*BA.06 alleles remain indistinguishable despite routine serological testing and ABO genotyping. To the best of the author’s knowledge, this is the first case report of these variants discovered in a Cambodian individual residing in Korea.

Weak D and partial D result in quantitative and qualitative changes in RhD protein expression respectively. It is difficult to discriminate weak D from partial D by serological tests alone. RHD genotyping is a useful method that complements serological results. A 64-year-old woman visited our hospital for microvascular decompression surgery. Her blood type was O, D negative by manual tube test and as per auto analyzer results (QWALYS-3 system; DIAGAST, France). Weak D and partial D tests were performed by using two different monoclonal anti-D reagents (Bioscot; Merck Millipore, UK; Bioclone; Ortho Clinical Diagnostics, USA) and a panel of nine monoclonal antibodies, including anti-D IgM and IgG (D-Screen; DIAGAST, France). However, these serological tests could not confirm the subtype of partial D. Therefore, sequencing of RHD exon 1 to 10 was additionally performed for the patient and the case was revealed to be partial DVI type 3.

Weak D type 102 allele (RHD*01W.102) carrying a missense variant (c.73A＞T, p.Ile25Phe) in exon 1 of the RHD has not been reported in Koreans to date. This is the first report of the weak D type 102 allele in the Korean population. The proposita, a 35-year-old woman, showed a serological weak D phenotype in routine RhD typing. Sequencing of all 10 RHD exons and zygosity testing targeting the hybrid Rhesus box revealed this proposita to harbor the weak D type 102 allele, as well as an RHD deletion (RHD*01W.102/RHD*01N.01). Family studies showed that the weak D type 102 allele was also present in her father and older brother (both assumed to be RHD*01W.102/RHD*01) but not in her mother and oldest brother (both assumed to be RHD*01/RHD*01N.01). In silico analysis of the replacement of isoleucine by phenylalanine at position 25 was done with PolyPhen-2, SIFT, and PROVEAN. While PolyPhen-2 predicted the variant as benign, SIFT and PROVEAN predicted it as damaging and deleterious, respectively, suggesting RHD c.73A>T (I25F) as the cause of serologic weak D phenotype. This patient should be treated as D-negative, when transfusion is needed.

No abstract available.
Antibodies ; Hemodilution ; Humans ; Korea

RHD genotyping is a useful adjunct to serologic testing. Although the use of RHD genotyping in the detection of Asia type DEL in serological D negative Koreans is gradually increasing, it is rarely requested for patients with a known weak D phenotype. This paper reports the first Korean case of a 52-year-old female patient with serologic weak D phenotype and weak D type 33 (c.520G>A at exon 4 of RHD) identified by RHD exon 1 to 10 sequencing. In silico analysis predicted that the RHD c.520G>A (V174M) results in a serologic weak D phenotype.
Asia ; Computer Simulation ; Exons ; Female ; Humans ; Korea ; Middle Aged ; Phenotype ; Serologic Tests

D antigens are clinically significant, and routine tests on the D antigen requires the inclusion of weak D testing, which is performed using indirect antihuman immunoglobulin methods. On the other hand, exact typing of the D type of an individual can be done more precisely with RHD genotyping, which is a useful tool in cases where the RHD gene is intact. The majority of weak-D or partial-D cases are from single nucleotide changes or hybridization of RHD and RHCE genes. Nevertheless, frameshift mutations can also result in weak or partial-D. The characteristics of a frameshift mutation is typically a change in protein product after a problematic mutation and early termination of transcription, leading into truncated protein products. This paper reports a D-variant case with RHD 711delC along with a review of the relevant literature. In addition, the results of software analysis are reported.
Frameshift Mutation ; Genotype ; Hand ; Immunoglobulins