National Center for Advancing and Translational Sciences Genetic and Rare Diseases Information Center, a program of the National Center for Advancing and Translational Sciences

Primary hypomagnesemia with secondary hypocalcemia


Other Names:
HOMG1; HSH; PHSH; HOMG1; HSH; PHSH; Hypomagnesemic tetany; Hypomagnesemia caused by selective magnesium malabsorption; Hypomagnesemia intestinal type 1; Intestinal hypomagnesemia with secondary hypocalcemia See More
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Familial hypomagnesemia with secondary hypocalcemia is a disease characterized by very low magnesium levels in the blood. The disease begins during the first months of life with generalized and recurrent seizures which do not improve with usual treatment. Additional features include tetany (spasms of the hands and feet, cramps, spasm of the voice box (larynx), and overactive neurological reflexes), failure to thrive, restlessness, tremors, muscle spasms, and bluish skin around the mouth (perioral cyanosis). Abnormal heart rhythm (cardiac arrhythmia) may be observed.[1][2] The low levels of magnesium result in low levels of parathyroid hormone (PTH) and in low levels of calcium in the bloods (hypocalcemia).[3] It is caused by mutations in the TRPM6 gene. Inheritance is autosomal recessive. Untreated, the disease may be fatal or lead to severe neurologic damage. Treatment involves giving magnesium, usually in the vein (intravenously), followed by life-long high-dose oral magnesium.[1][2]
Last updated: 7/20/2016

This table lists symptoms that people with this disease may have. For most diseases, symptoms will vary from person to person. People with the same disease may not have all the symptoms listed. This information comes from a database called the Human Phenotype Ontology (HPO) . The HPO collects information on symptoms that have been described in medical resources. The HPO is updated regularly. Use the HPO ID to access more in-depth information about a symptom.

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Medical Terms Other Names
Learn More:
HPO ID
Percent of people who have these symptoms is not available through HPO
Autosomal recessive inheritance 0000007
Hypocalcemia
Low blood calcium levels
0002901
Hypomagnesemia
Low blood magnesium levels
0002917
Infantile onset
Onset in first year of life
Onset in infancy
[ more ] 		0003593
Muscle spasm 0003394
Seizure 0001250
Tetany
Intermittent involuntary muscle spasm
0001281
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Last updated: 7/1/2020

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Healthcare Resources

Related diseases are conditions that have similar signs and symptoms. A health care provider may consider these conditions in the table below when making a diagnosis. Please note that the table may not include all the possible conditions related to this disease.

Conditions with similar signs and symptoms from Orphanet
Differential diagnosis includes Gitelman and Bartter syndromes, familial primary hypomagnesemia with hypercalciuria and nephrocalcinosis without severe ocular involvement (see these terms), and nutritional rickets.
Visit the Orphanet disease page for more information.

These resources provide more information about this condition or associated symptoms. The in-depth resources contain medical and scientific language that may be hard to understand. You may want to review these resources with a medical professional.

In-Depth Information

  • Online Mendelian Inheritance in Man (OMIM) is a catalog of human genes and genetic disorders. Each entry has a summary of related medical articles. It is meant for health care professionals and researchers. OMIM is maintained by Johns Hopkins University School of Medicine. 
  • Online Mendelian Inheritance in Man (OMIM) lists the subtypes and associated genes for Primary hypomagnesemia with secondary hypocalcemia in a table called Phenotypic Series. Each entry in OMIM includes a summary of related medical articles. It is meant for health care professionals and researchers. OMIM is maintained by Johns Hopkins University School of Medicine.
  • Orphanet is a European reference portal for information on rare diseases and orphan drugs. Access to this database is free of charge.

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  1. Primary hypomagnesemia with secondary hypocalcemia. Orphanet. 2014; http://www.orpha.net/consor/cgi-bin/OC_Exp.php?lng=EN&Expert=30924.
  2. Hypomagnesemia 1, intestinal. OMIM. 2016; http://omim.org/entry/602014.
  3. Lainez S & cols. New TRPM6 missense mutations linked to hypomagnesemia with secondary hypocalcemia. Europ. J. Hum. Genet. 2014; 22:497-504. http://www.nature.com/ejhg/journal/v22/n4/full/ejhg2013178a.html.