New kidney stone component identified

French scientists have identified a new calcium compound in kidney stones which adds to the growing number of minerals identified in living species and will be of interrest to clinicians. The stones were supposedly passed by a young boy and could not be characterised by the usual techniques of FTIR spectroscopy and X-ray fluorescence. However, X-ray diffraction revealed them to consist of calcium glycine trihydrate, as reported in Acta Crystallographica Section C. The full chemical name is poly[[di-μ-aqua-bis(glycinato-κ²N,O)calcium(II)] monohydrate].

Although there is no doubt about the structure, there remains some doubt concerning the origin of the stones because they were passed on by hand from patient to physician. Their unusual structure prompted the scientists to conclude that they did not originate from the urinary tract and may be spurious. In fact, they may be false stones associated with Munchausen syndrome, since the boy's father has a history of recurrent kidney stone formation. Calcium glycinate is a common ingredient in cosmetics and is a dietary supplement.

Image: US NLM/NIH