SLC7A7 and chronic kidney disease: Confirming this hypothesis, assessments of kidney function in Slc7a7 knockout mice revealed clear signs of early-stage chronic kidney disease, characterized by decreased serum albumin and total protein levels, elevated blood urea nitrogen levels (Fig. 3d–f) and a reduced glomerular filtration rate (Webster et al. 2017), as previously reported (Bodoy and Sotillo 2019).