Table 1.

Phenotypes of various mutant mice compared to wild-type littermates

Characteristic	Wild-type	Fgf23−/−	klotho−/−	Fgf23−/−/klotho−/−
Gross appearance
Body weight	Normal	Reduced	Reduced	Reduced
Growth retardation	Absent	Present	Present	Present
Physical activity	Normal	Sluggish	Sluggish	Sluggish
Generalized atrophy
Spleen atrophy	Absent	Present	Present	Present
Muscle wasting	Absent	Present	Present	Present
Skin atrophy	Absent	Present	Present	Present
Intestinal atrophy	Absent	Present	Present	Present
Hypogonadism	Absent	Present	Present	Present
Morphological changes
Atherosclerosis/arteriosclerosis	Absent	Present	Present	Present
Ectopic calcifications	Absent	Present	Present	Present
Skeletal mineralization	Normal	Impaired	Impaired	Impaired
Emphysema	Absent	Present	Present	Present
Molecular changes
Renal 1a(OH)ase expression	Normal	Increased	Increased	Increased
Renal NaPi2a expression	Normal	Increased	Increased	Increased
Biochemical changes
Serum 1,25(OH)2D3	Normal	High	High	High
Serum phosphate	Normal	High	High	High
Serum calcium	Normal	High	High	High
Serum PTH	Normal	Low	Low	Low
Overall affect
Infertility	Absent	Present	Present	Present
Lifespan	Normal	Short	Short	Short

Data from refs. 18, 28, 29, 32.