Transfusion practice blind spot in para-Bombay: A case report.

H-deficient phenotype individuals with absent or weak anti-H activity may remain undetected on standard routine blood grouping. We report a case of a 59-year-old-man presented with symptomatic anaemia secondary to upper gastrointestinal bleed with haemoglobin level of 68 g/L who required two units of packed red blood cells. He was previously grouped as O Rh D positive and had a history of uneventful multiple blood transfusions. His latest pre-transfusion investigations showed ABO discrepancy between forward and reverse blood grouping, pan-agglutination in both antibody screening and identification with negative direct Coombs test and autocontrol. Further testing including anti-H lectin test and saliva secretor study confirmed that the patient blood group was para-Bombay B RhD positive. This case highlights that the para-Bombay phenotype can be mistakenly labelled as "O" if further investigations are not performed.

Two Novel α 1,2-Fucosyltransferase Alleles in an H-Deficient Phenotype Individual.

BACKGROUND: Abnormal α1,2-fucosyltransferase activity due to gene mutation results in decreased synthesis of H antigen and leads to an H-deficient phenotype. Here we studied the underlying molecular mechanisms in 7 Chinese blood donors with the H-deficient phenotype. METHODS: Red blood cell typing was performed using standard serologic tests, and ABO genotype was analyzed using ABO polymerase chain reaction with sequence-specific primer tests. The coding sequence of the FUT1 gene was amplified using the specific primers. The FUT1 alleles were identified by a pCRII-TOPO carrier for TOPO TA cloning sequencing. RESULTS: The H-deficient phenotype frequency was estimated to be approximately 1/30,000 (6/159,515) in the Chinese Han population. The FUT1 gene mutation was demonstrated in 6 Chinese blood donors with the H-deficient phenotype. In only 1 case, no mutation was detected. Novel FUT1 alleles were found in 1 donor. One of these novel FUT1 alleles showed nucleotide 35C>T and 748C>T site mutations that resulted in amino acid substitution of Ala to Val and Trp to Arg at positions 11 and 250, respectively. Another novel FUT1 allele had a nucleotide 655G>C site mutation, causing amino acid substitution of Leu to Val at position 219. CONCLUSIONS: Two novel FUT1 alleles, 35T+748T and 655C, were identified that may greatly diminish the activity of α1,2-fucosyltransferase and result in the H-deficient phenotype.