The Congenital 'Magnesium-Losing Kidney' REPORT OF TWO PATIENTS

A 39-year-old man with a lifelong history of tetany and hypocalcaemla was found to have hypomagnesaemla (0*29 mmol/1) due to renal magnesium loss. His asymptomatic 29-year-old brother had a similar disorder. Both were infertile and had severe oligospermia but normal endocrine function. They had medullary nephrocalcinosis and glomerular filtration rate was reduced. Renal biopsy showed patchy interstitial flbrosis and some glomerular sclerosis. Electron microscopy showed thickened basement membranes in damaged glomeruli and in tubules In areas of flbrosis. Tests of renal tubule function were normal. Hypocalcaemla and tetany were corrected by oral magnesium supplements which raised the serum magnesium level to around 0.54 mmol/1