Clinical feature: 

Definition: HSH is an autosomal recessive disorder characterized by severe hypomagnesemia and secundary hypocalcemia. The disorder is caused by disturbances in cellular magnesium transport in the kidney as well as in the bowel.

History: The dieseas has been first described by Paundier in 1968.

Clinical picture: Clinical manifestation is usually during infancy. Symptoms of severe hypomagnesemia and hypocalcemia dominate the clinical picture: Tetany and Seizures. Severe neurological injuries might develop and sometime the disease leads to death.
   Plasma magnesium is dramatically decreased 0.24 ± 0.11 mmol/l. Renal magnesium excretion is increased. Although plasme calcium is low 1.58 ± 0.33 mmol/l, this is not due to substantial renal losses.

Diagnostics: 

Diagnosis: The diagnosis is made when in patients with neuro-muscular complains serum magnesium is checked.

Differential: The two FHHNC variants are the most important differentials. In these diseases however hypomagnesimia is not so prominent and hypocalcimia is clearly caused by hypercaliuria.  » » » 
   Isolated hypomagnesemias (IDH/IRH) go without hypocalcemia and hypercalciuria.  » » » 

Literature: 

Paunier L et al. (1968) Primary hypomagnesemia with secondary hypocalcemia in an infant.