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Identification of the Kn a /Kn b polymorphism and a method for Knops genotyping
Author(s) -
Moulds J.M.,
Thomas B.J.,
Doumbo O.,
Diallo D.A.,
Lyke K.E.,
Plowe C.V.,
Rowe J.A.,
Birmingham D.J.
Publication year - 2004
Publication title -
transfusion
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.045
H-Index - 132
eISSN - 1537-2995
pISSN - 0041-1132
DOI - 10.1111/j.1537-2995.2004.00615.x
Subject(s) - genotyping , genotype , microbiology and biotechnology , loss of heterozygosity , biology , genetics , serology , polymerase chain reaction , typing , allele , antibody , gene
BACKGROUND: DNA mutations resulting in the McCoy and Swain‐Langley polymorphisms have been identified on complement receptor 1 (CR1)—a ligand for rosetting of Plasmodium falciparum ‐infected RBCs. The molecular identification of the Kn a /Kn b polymorphism was sought to develop a genotyping method for use in the study of the Knops blood group and malaria. STUDY DESIGN AND METHODS: CR1 deletion constructs were used in inhibition studies of anti‐Kn a . PCR amplification of Exon 29 was followed by DNA sequencing. A PCR‐RFLP was developed with Nde I, Bsm I, and Mfe I for the detection of Kn a /Kn b , McC a /McC b , and Sl1/Sl2, respectively. Knops phenotypes were determined with standard serologic techniques. RESULTS: A total of 310 Malian persons were phenotyped for Kn a with 200 (64%) Kn(a+) and 110 (36%) Kn(a–). Many of the Kn(a–) exhibited the Knops‐null phenotype, that is, Helgeson. The Kn a/b DNA polymorphism was identified as a V1561M mutation with allele frequencies of Kn a (V1561) 0.9 and Kn b (M1561) 0.1. CONCLUSION: The high frequency (18%) of Kn b in West African persons suggests that it is not solely a Caucasian trait. Furthermore, because of the high incidence of heterozygosity as well as amorphs, accurate Knops typing of donors of African descent is best accomplished by a combination of molecular and serologic techniques.