Rare ABO Allele Encoding Glycosyltransferase with Dual Specificity Found in a Cambodian Individual with the A 2 B Phenotype / 대한수혈학회지

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.

Rare ABO Allele Encoding Glycosyltransferase with Dual Specificity Found in a Cambodian Individual with the A 2 B Phenotype / 대한수혈학회지

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 Type 102 Found in a Family Study: The First Case in Korea / 대한수혈학회지

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.

Cold Agglutinin Disease due to Anti-Pr Cold Autoantibody in a Patient with Bone Marrow Transplantation / 대한수혈학회지

Cold agglutinin disease (CAD) is a most common autoimmune hemolytic anemia (AIHA) induced by cold antibody. CAD represents approximately 16-32% of AIHA cases and causative cold autoantibodies commonly show specificity against the I antigen. We report a case of cold agglutinin disease with anti-Pr cold autohemolysin. A 20 year old woman with a history of bone marrow transplantation was admitted with nausea, vomiting, and pallor. Direct antiglobulin tests were positive with IgG and C3d specific AHG reagents. Cold agglutinin titer was as high as 1:1024 at 4degrees C, 1:16 at room temperature, negative at 37degrees C. The agglutinin titer was diminished after treatment with protease, ficin and immunohematologic results of cold agglutinin was compatible with anti-Pr specificity. In unexpected antibody identification test, anti-M which showed reactivity at anti-human globulin phase was identified. Washed and prewarmed 16 units of A+, M antigen negative red blood cells were transfused. After two weeks, patient was improved with steroid therapy and experienced relief of fever and hemolysis, and she was discharged.

Two Case Reports of Spinal Muscular Atrophy(SMA) Confirmed by Molecular Genetic Studies / 대한임상병리학회지

We present two cases of the patients with spinal muscular atrophy(SMA) confirmed by molecular genetic studies. The first one is 1-year-old female child with SMA type II(Dubowitz disease) who visited pediatric outpatient for developmental delay. She presented lower extremity hypotonia which progress to upper extremities and inability to sit alone. Spinal cord MRI showed normal findings but the needle electromyography suggested the possibility of myopathy. Following muscle biopsy findings were consistent with spinal muscular atrophy and PCR-SSCP(polymerase chain reaction-single strand conformation polymorphism) analysis showed homozygous deletion of telomeric SMN(survivor motor neuron) exon 7. The second is a 19-year-old female with SMA type III(Kugelberg-Welander disease) who visited neurologic outpatient for limbs weakness. She presented slowly progressive gait disturbance without muscle atrophy. The significantly decreased motor power of proximal limbs was observed. And findings of electromyography and muscle biopsy were consistent with spinal muscular atrophy. PCR-SSCP analysis revealed homozyous deletion of exon 7 of telomeric SMN and deletion of exon 8 of centromeric SMN gene. PCR analysis for NAIP(neuronal apoptosis inhibitory protein) exon 5 and 13 revealed no deletion in both cases. Molecular genetic analysis for SMN gene will be very useful for rapid diagnosis of spinal muscular atrophy.