SLC34A2 and kidney disorder: This is supported by studies showing that calcitriol increases expression of NaPi‐2b and intestinal phosphorus uptake or transport as assessed by in vitro and ex vivo methods in rodent models, (18, 20, 43, 44, 45, 46) and conversely, vitamin D‐receptor knockout mice have lower expression of NaPi‐2b.(47) However, in vivo absorption studies have shown a general lack of effect of kidney disease on intestinal phosphorus absorption efficiency.