hypomagnesemia type 1; hypomagnesemia with secondary hypocalcemia (HSH)

Introduction

Hereditary defect in Mg+2 absorption

Pathology

• defect in Mg+2 absorption resulting in hypomagnesemia
• hypocalcemia secondary to parathyroid failure resulting from Mg+2 deficiency
• calcinosis

Genetics

• autosomal recessive disease
• mutations in the TRPM6 gene

Clinical manifestations

• neurologic symptoms of hypomagnesemic & hypocalcemia
  • seizures & muscle spasms, during infancy

Laboratory

• serum Mg+2 low
• 24 hour urine Mg+2
• serum Ca+2 low

Complications

• untreated, the disorder may be fatal or may result in neurological damage

Management

• restoring concentrations of serum Mg+2 to normal values by high-dose Mg+2 supplementation can overcome defect in Mg+2 absorption & in serum Ca+2.

More general terms

• familial hypomagnesemia

Additional terms

• transient receptor potential cation channel subfamily M member 6; channel kinase 2; melastatin-related TRP cation channel 6 (TRPM6, CHAK2)

Database

• OMIM: https://mirror.omim.org/entry/602014