Clinical feature: 

Definition: Isolated dominant hypomagnesemia (IDH) is an autosomal dominant disorder of magnesium wastage. The mild hypomagnesemia occurs without other electrolyte abnormalities. A mutation in the FXYD2 gene is responsible for this disorder.

History: An autosomal dominant magnesium wasting disorder has been first described by Geven in 1987.

Diagnostics: 

Differential: Isolated recessive hypomagnesemia (IRH) inherits recessively, so we would not expect a family history but consanguinity.  » » » 
   Hypomagnesemia with hypercalciuria and nephrocalcinosis (FHHNC) is characterized by renal calcium wastage.  » » » 
   Hypomagnesemia with secondary hypocalcemia (HSH) has no hypercalciuria, too, but hypocalcemia.  » » » 

Literature: 

Geven WB et al. (1987) Renal magnesium wasting in two families with autosomal dominant inheritance.