FXYD domain-containing ion transport regulator 8 (FXYD8), also known as FXYD domain containing ion transport regulator 6 pseudogene 3 (FXYD6P3), is a member of the FXYD protein family that is involved in the modulation of NKA activity in the kidneys. The human FXYD8 gene is located on the X chromosome. However, the gene is located on chromosome 9 in the mouse and chromosome 8 in the rat.