- Association of the F352V variant of the Klotho gene with bone mineral density. Riancho, J.A., Valero, C., Hernández, J.L., Ortiz, F., Zarrabeitia, A., Alonso, M.A., Peña, N., Pascual, M.A., González-Macías, J., Zarrabeitia, M.T. Biogerontology (2007)