Hypomagnesemia 1 intestinal (Hypomagnesemia 1 Intestinal) - Gen TRPM6.

Intestinal hypomagnesemia 1 with the secondary hypocalcaemia, is a disturbance due to a primary defect in the intestinal absorption of magnesium. It is characterized by low serum concentrations of magnesium along with normal renal secretion magnesium, secondary hypocalcaemia and calcinocis. Affected individuals exhibit neurological symptoms of hypocalcemia hypomagnesemic, including seizures and muscle spasms during childhood. Hypocalcemia is a secondary consequence of parathyroid insufficiency and resistance to parathyroid hormone as a result of the significant deficiency of magnesium. In general, the disease manifests itself during the first months of life with seizures or signs of increased neuromuscular excitability. If left untreated, the disease can be fatal or cause serious neurological damage.

This process is due to mutations in the gene TRPM6, located on the long arm of chromosome 9 (9q21.13). This gene is predominantly expressed in kidney and colon, and encodes a protein containing an ion channel domain and protein kinase domain. It is crucial for homeostasis magnesium, and plays an essential role in epithelial transport of magnesium and magnesium absorption in the intestine and kidney.

Mutations in this gene are associated with hypomagnesemia with secondary hypocalcemia. Variants have been observed alternative transcript encoding different isoforms linked to this gene. Mutations in the gene cause a decrease in the expression of magnesium channel in the distal tubule, causing urinary magnesium loss.  

This disease is inherited in an autosomal recessive pattern, that is, both copies of the gene in every cell must have mutations for alteration is expressed. The parents of an individual with an autosomal recessive disease have a copy of the mutated gene, but usually show no signs and symptoms of the disease.  

Tests in IVAMI: in IVAMI perform detection of mutations associated with intestinal hypomagnesaemia 1 by the complete PCR amplification of exons TRPM6 gene, and subsequent sequencing.

Samples recommended: EDTA blood collected for separation of blood leukocytes, or impregnated sample card with dried blood (IVAMI may mail the card to deposit the blood sample).