A Pedigree Investigation of H-antigen Deletion Caused by Mutation of 658 C to T in the FUT1 Gene.

H-antigen deletion is often caused by FUT1 gene mutation, which is a very rare blood group. In this case, the H-antigen phenotype, FUT1, FUT2 sequences, and family genetic investigation of a 26-year-old patient (proband) and her three family members were studied. The results showed that the proband and little her brother were H-deficient phenotype, their ABO genotype of both was A/O1, her father was A/B, and her mother was O1/O1. The proband and her little brother's FUT1 phenotype were both h3|h3, with a homozygous mutation 658C > T in their FUT1 gene, and the FUT1 phenotype of their parents' were H|h3, with a heterozygous mutation (658C > T) in their FUT1 gene. The result of whole gene sequencing showed that the father of the proband had a deletion of CHR19.49,255,178-49,257,177 in the FUT1 gene (hg19 was used as the reference). The results of the family investigation showed that the mutation of site 658 in the FUT1 gene between offspring and parents was consistent with Mendelian inheritance law.

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.

Aberrant ABO B Phenotype with Irregular Anti-B Caused by a Para-Bombay FUT1 Mutation.

BACKGROUND: Routine ABO blood group typing for pre-transfusion testing of a male Austrian patient of Far Eastern origin showed discrepant results with an apparently weak blood group B phenotype and irregular anti-B. MATERIALS AND METHODS: ABH phenotyping and cross-matching was done by standard serologic techniques and levels of H expression were determined by flow cytometry. ABO gene sequencing including regulatory regions as well as analysis of FUT1 (H), FUT2 (Secretor), and FUT3 (Lewis) were carried out. RESULTS: While monoclonal ABO antigen typing indicated blood group O, weak agglutination reactions using polyclonal human anti-B and anti-AB were seen. In reverse typing at room temperature, the plasma was reactive with A1 and A2 RBCs and negative with B and O cells, whereas at 4°C, anti-B reactivity was found. The indirect anti-globulin cross-match of the patient's plasma was positive with group B RBCs and negative with group O RBCs. Sequencing analysis showed the presence of ABO*B.01 (B114) allele and homozygosity for the FUT1 mutation c.551_552delAG. Flow cytometry demonstrated trace amounts of H antigen on the patient's RBCs. CONCLUSION: While a functional B allele was found, analysis of FUT1 and FUT2 genes revealed the presence of a rare para-Bombay genotype OhB. Interestingly, no anti-H but irregular anti-B was found in the patient's plasma, responsible for the positive cross-match with group B RBCs. Even though very rare and not reported for the European population, the presence of an H-deficient phenotype should be considered when investigating individuals with an unusual ABO blood group type.

The First Comprehensive Study of H-Deficient Phenotypes in Iran.

BACKGROUND: The lack of correct blood grouping practices can lead to missing of the rare Bombay Oh phenotype and subjecting patients to the risk of severe hemolytic transfusion reaction. In the absence of blood donor registry, transfusion management of patients is a challenge. We performed this study in order to estimate the prevalence of the Bombay blood group (Oh) in Iran and to determine whether consanguinity plays a role in the prevalence of Oh group. METHODS: This is a descriptive study in the Immunohematology Reference Laboratory of the Iranian Blood Transfusion Organization (IBTO) Tehran, Iran, over a period of 7 years. All donor blood samples showing blood group O and a strong initial reaction with blood group O RBC control cells were tested with anti-H lectin. Also blood samples from blood group O patients were tested with anti-H lectin if all cells on both antibody screening tests and antibody identification panels were reactive with negative auto control test. Specialized tests like adsorption/elution technique and inhibition assay for determination of secretor status were performed on Oh cases. Any history of consanguineous marriages were recorded. All variables were categorical variables, and percentage and proportions were calculated manually. RESULTS: Analysis of the results of over 7 million first-time blood donors in Iran showed that the most common ABO blood group was O, with 2,520,000 (36%) subjects. 56 Oh individuals' (donors and patients) phenotypes (0.0008%) were detected. Consanguinity was observed in 50 cases (89%). CONCLUSIONS: This study shows that the prevalence of Bombay blood group in the general population of Iran is relatively high (0.0008%) and associated with consanguineous marriage. Thus, consanguinity is still an important risk factor present.

A Very Rare Case with Particular H-deficient Phenotypes.

Bombay phenotype, H partially deficient non secretor phenotype and Para-Bombay phenotype are rare blood groups with deficiency or absence of H antigen. A 52-year-old female with Chronic suppurative otitis media was referred to our hospital. The primary serologic results of ABO blood typing were discrepant in forward and reverse grouping. Further, the saliva secretion tests, the pedigree studies and the sequence analysis were performed to confirm the rare phenotype. The patient was diagnosed as a variant H-deficient phenotype, secretor (para-bombay). Red cells of the patient have no H antigens, and it's a very interesting thing that there were two opposite results in the saliva test by using different anti-H. The test showed that H substances were present in the saliva by using anti-H from Libo Biotechnology Co, while which were absent by using anti-H from Shanghai blood center. The patient's Lewis phenotype was Le (a-b+). Anti-HI was present in the sera of her. The sequence of the ABO gene of the patient was 261delG and 467C>T heterozygote by direct DNA sequencing and was assigned as A102/O01. There were two mutations of the patient's FUT1, 328G/A and 658C/T, which were identified by DNA sequencing compared with the reference sequence (GenBank, NG_007510.2). In this case, we report a patient with particular H-deficient phenotype, secretor, which showed opposite results in the saliva test by using anti-H from different sources. We suspect that it is a variant of para-Bombay phenotype.

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.

Molecular genetics analysis and frequency survey of H deficient phenotype / 中国输血杂志

Objective To survey the frequency of H deficient phenotype in blood donor population and analyze the serological and genetic characteristics of these individuals.Methods The H deficient phenotype was screened with anti-H monoclonal antibody.The ABO type was screened with serological method and with sequence specific primer polymerase chain reaction(PCR-SSP).FUT1 and FUT2 gene sequences were analyzed with direct sequencing of PCR products and gene cloning products.Result Of 85 390 blood donors,ten individuals were identified to be para-Bombay phenotype.Four h alleles were found in 14 para-Bombay phenotype individuals,h1(nt547-552?ag),h2(nt880-882?tt),h3(nt658c→t),and h_(new-2)(nt328g→a).The FUT1 genotypes of these para-Bombay individuals were h1/h1(6 individuals),h1/h2(7 individuals) and h3/h_(new2)(1 individual),and the frequency of 4 allele were 67.85%(h1),25%(h2),3.57%(h3),and 3.57%(h_(new-2)),respectively.FUT2 gene was analyzed in 12 para-Bombay phenotype individuals,and a mutation of nt357c→t was detected in all FUT2 gene,another mutation of nt716g→a were heterozygous in 5 individuals with h1/h2 genotype.No null FUT2 gene was detected.In serological analysis,all atypical anti-A or anti-B antibody of 14 para-Bombay individuals were inactive at 37℃,7 individuals had active anti-H antibody at 37℃.Conclusion The frequency of H deficient phenotype in Fujian population is about 1:8 500.The h1 and h2 alleles are predominant in Fujian H deficient individuals on h1-Se~(357) and h2-Se~(357,716) haplotype background.