XK (protein)
protein-coding gene in the species Homo sapiens
XK (also known as Kell blood group precursor) is a protein found on human red blood cells and other tissues which is responsible for the Kx antigen which helps determine a person's blood type.
Clinical significance
The Kx antigen plays a role in matching blood for blood transfusions.
Mutation of XK protein may lead to McLeod syndrome, a multi-system disorder characterized by hemolytic anemia, myopathy, acanthocytosis, and chorea.
XK is located on the X chromosome (cytogenetic band Xp21.1) and absence of the XK protein is an X-linked disease.
Clinical diagnostic
Clinical testing in patient care for Kx antigen follows published minimum quality and operational requirements, similar to red cell genotyping for any of the other recognized blood group systems. Molecular analysis can identify gene variants (alleles) that may affect Kx antigen expression on the red cell membrane.
Function
XK is a membrane transport protein of unknown action.
“XK (protein)” enters the record as protein-coding gene in the species Homo sapiens. Crown Archives preserves that source wording while asking what protein, protein-coding and gene can confirm, complicate or overturn.
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Datasets, specimens, observations and peer-reviewed methods provide the appropriate test for the technical claims summarized here. The source revision retrieved here is dated May 19, 2026. The linked authority identifier is Q6168793. None of the 0 selected statements returned an explicit reference.
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