Mutations that diminish expression of Kell surface protein and lead to the Kmod RBC phenotype.

Background: Kmod is an inherited rare RBC phenotype characterized by weak but detectable expression of high-incidence Kell antigens.

Study Design And Methods: The 19 exons and the intron-exon regions of the KEL gene from four unrelated Kmod individuals were sequenced and compared to wild-type KEL. To study the mechanisms by which the mutations result in depression of Kell antigens, mutant and wild-type Kell proteins were expressed in 293T cells and the amounts of protein present on the cell surface were determined.

Point mutations causing the McLeod phenotype.

Background: The McLeod phenotype is defined by absence of Kx, weakening of Kell system antigens, and acanthocytosis. Individuals with the McLeod phenotype usually develop late-onset neuromuscular abnormalities. Gene deletions, insertions, and point mutations that affect RNA splicing or that lead to premature stop codons have been reported to cause the McLeod phenotype.