Clinical feature: 

Definition: Isolated recessive hypomagnesemia is an autosomal recessive disorder characterized by normocalcemia and mental retardation. The underlying mutation affects pro-EGF sorting and prevents the hormone's effect on TRPM6 the magnesium channel in the dital convoluted tubule and probably in the intestine.

History: This disorder has recently (2007) detected by Groenestege. By investigating this disorder, the first hormone affecting magnesium homeostasis has been detected.

Epidemiology: A single family has been described yet.

Diagnostics: 

Differential: The dominant type of isolated hypomagnesemia (IDH) only has a different inheritance pattern in consequence of which if not a de novo mutation, family history is instructive.  » » » 
   Hypomagnesemia with hypercalciuria and nephrocalcinosis (FHHNC) is characterized by hypocalcemia, renal calcium wastage, and nephrocalcinosis.  » » » 
   Hypomagnesemia with secondary hypocalcemia (HSH) has no hypercalciuria, too, but hypocalcemia.  » » » 

Literature: 

Groenestege WM et al. (2007) Impaired basolateral sorting of pro-EGF causes isolated recessive renal hypomagnesemia.