2023年5月8日 · Additionally, a minor Duffy phenotype is the Fyx or [Fy (b+x)]. In this phenotype, the antigen is weakly expressed as Fyb and is determined by serological adsorption and elution techniques and DNA sequencing. FYX allele encodes weakly expressed Fyb antigen, which sometimes may not be detected by anti-Fy.

FY has two major codominant alleles, FYA and FYB, which result from a SNP (125G→A), and the corresponding Fy a and Fy b antigens differ by a single amino acid (G42D). Individuals who are homozygous for a -33T→C SNP in the erythroid promoter region of the FYB allele have the phenotype Fy (a-b-) and do not express Duffy antigens on their RBCs.

Fy (a-b-), or Duffy null, is the major phenotype in African and American blacks and is characterized by the presence of Fy (b) on nonerythroid cells, but an absence of Fy (b) on erythrocytes. The Fy (a-b-) phenotype is associated with complete resistance to infection by the malarial parasite Plasmodium vivax (see 611162).

2004年11月16日 · The molecular analysis for FYA, FYB, FYB ES (GATA box mutation nt -33T-C), and FYB Weak (mutations 265 C-T, and 298 G-A) alleles, were performed by PCR-RFLP. The PCR products were digested by Ban I for FYA and FYB identifications; by Sty I for GATA box mutation; Acy I and Mwo I for 265 C-T and 298 G-A mutations, respectively.

1998年9月15日 · We concluded that the Fyb weak donors carried the FY*X allele at the FY locus and that the Fy x antigen corresponds to highly reduced expression of a grossly normal Fy b polypeptide caused by the Arg89Cys substitution. Because FY is a single copy gene, this defect should also affect DARC expression in nonerythroid cells.

The Duffy blood group antigens are encoded by the Duffy gene with its three major alleles: Fy*A (Fya+), Fy*B (Fyb+), and a nonexpressed Fy*Fy (Fya-b-), which is most commonly found among black people. Additionally, a fourth allele, Fyx, is found among white people and defined as weak Fyb not detecta …

Two donors whose erythrocytes typed weakly positive for Fyb and appeared to be Fyx were homozygous for FY2 by DNA testing. DNA sequencing of the regulatory region for Duffy found a mutation in an Sp1 binding site in the Fyx donor.

2001年6月1日 · Tournamille et al. (1998) and Olsson et al. (1998) described a Duffy allele, FYB-weak (FYB-WK), or FYX, in approximately 3.5% of the population that, because of an arg89-to-cys (R89C) substitution in the first cytoplasmic domain of DARC, results in reduced levels of protein, lower antigen expression, and reduced ability to bind chemokines.

2017年2月28日 · I would assume if the FyB allele is present, even if weak, you would want to call them FyB pos as a donor, but if it is a weak expression and as a recipient they could possibly make anti FyB you'd want that documented as well!

2002年1月4日 · In the Fyx genes of five unrelated British and Swedish donors with the Fy (a+b+ weak) phenotype we found two missense mutations predicting amino acid changes Arg89Cys and Ala100Thr in the FY glycoprotein. The same mutations were found in two Fy (a−b+ weak) samples from individuals of Swedish and Algerian origin.