Klotho is a type-I membrane protein that is related to β-glucuronidases. Reduced production of this protein has been observed in patients with chronic renal failure (CRF), and this may be one of the factors underlying the degenerative processes (e.g., arteriosclerosis, osteoporosis, and skin atrophy) seen in CRF. Also, mutations within this protein have been associated with ageing and bone loss.

Klotho is a transmembrane protein that, in addition to other effects, provides some control over the sensitivity of the organism to insulin and appears to be involved in aging. Its discovery was documented in 1997 by Kuro-o et al. The name of the gene comes from Klotho or Clotho, one of the Moirae, or Fates, in Greek mythology.