Point Mutations and Deletion Responsible for the Bombay H null and the Reunion H weak Blood Groups

Abstract

Objective: Definition of the molecular basis of the Reunion and the Bombay red cell and salivary H-deficient phenotypes. Methods: Sequence and expression of FUT1 and FUT2 genes from H-deficient individuals. Family segregation analysis of the mutations responsible for the fucosyltransferase defects of H, secretor and Lewis systems. Results: The Indian red cell H null Bombay phenotype depends on a new mutation of the FUT1 gene. T725 → G changing Leu242 → Arg. Their salivary nonsecretor phenotype is secondary to a complete deletion of the FUT2 gene. The red cell H weak Reunion phenotype depends on another new mutation of FUT1, C349 → T which induces a change of His117 → Tyr. Their salivary nonsecretor phenotype is due to the known Caucasian inactivating mutation G428 → A. Conclusion: Single prevalent FUT1 and FUT2 point mutations and a deletion are responsible for the Indian Bombay H null and the Reunion H weak phenotypes found on Reunion island. This is in contrast with other H-deficient phenotypes where sporadic nonprevalent inactivating mutations are the rule.

Determination of LewisFUT3gene mutations by PCR using sequence-specific primers enables efficient genotyping of clinical samples

“…The PCR reactions were run in 15 µl with 5µl of each primer mix ( The FUT3 PCR-SSP assay was initially developed on DNA samples from blood donors, not included in this study but with known FUT3 genotypes [Elmgren et al, 1996;Fernandez-Mateos et al, 1998]. The final design of each primer-pair is shown in Tables 1 and 2.…”

Polymorphism of the human ABO‐Secretor locus (FUT2) in four populations in Asia: indication of distinct Asian subpopulations

“…In addition, we have reported three recombinant FUT2 alleles as nonfunctional alleles : one was the fusion gene (se fus ), consisting of the 5h region of a pseudogene of FUT2 (Sec1) and the 3h region of the FUT2 in Japanese individuals (Koda et al 1996 ;Liu et al 1999), while the other two were distinct and included complete deletion of the FUT2 (se del and se del# ) generated by Alu-Alu recombination (Koda et al 1997Pang et al 2000). The se del was originally identified in Indian individuals with the classical Bombay phenotype (Koda et al 1997 ;Fernandez-Mateos et al 1998) and also recently found in a Bangladeshi population with a high frequency (0n074) (Pang et al 2000). The se del# has been found in Samoans (Pang et al 2000).…”

Carbohydrate Blood Groups

“…One nonfunctional allele, se 6 , is the result of a fusion gene between FUT2 (ie, Se) and the adjacent upstream Sec1 pseudogene. 86,87 This large deletion is mediated by the presence of Alu sequences, 88 many of which are present in this chromosomal region. Finally, the complete deletion of the entire FUT2 gene is seen in individuals with the classical Bombay phenotype (see below); this allele is denoted as se del .…”