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Disease Profile

Primary hypomagnesemia with secondary hypocalcemia

Prevalence estimates on Rare Medical Network websites are calculated based on data available from numerous sources, including US and European government statistics, the NIH, Orphanet, and published epidemiologic studies. Rare disease population data is recognized to be highly variable, and based on a wide variety of source data and methodologies, so the prevalence data on this site should be assumed to be estimated and cannot be considered to be absolutely correct.


US Estimated

Europe Estimated

Age of onset





Autosomal dominant A pathogenic variant in only one gene copy in each cell is sufficient to cause an autosomal dominant disease.


Autosomal recessive Pathogenic variants in both copies of each gene of the chromosome are needed to cause an autosomal recessive disease and observe the mutant phenotype.


dominant X-linked dominant inheritance, sometimes referred to as X-linked dominance, is a mode of genetic inheritance by which a dominant gene is carried on the X chromosome.


recessive Pathogenic variants in both copies of a gene on the X chromosome cause an X-linked recessive disorder.


Mitochondrial or multigenic Mitochondrial genetic disorders can be caused by changes (mutations) in either the mitochondrial DNA or nuclear DNA that lead to dysfunction of the mitochondria and inadequate production of energy.


Multigenic or multifactor Inheritance involving many factors, of which at least one is genetic but none is of overwhelming importance, as in the causation of a disease by multiple genetic and environmental factors.


Not applicable


Other names (AKA)



Congenital and Genetic Diseases; Kidney and Urinary Diseases; Metabolic disorders


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]


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.

Medical Terms Other Names
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Percent of people who have these symptoms is not available through HPO
Autosomal recessive inheritance
Low blood calcium levels
Low blood magnesium levels
Infantile onset
Onset in first year of life
Onset in infancy

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Muscle spasm
Intermittent involuntary muscle spasm

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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.


  1. Primary hypomagnesemia with secondary hypocalcemia. Orphanet. 2014; https://www.orpha.net/consor/cgi-bin/OC_Exp.php?lng=EN&Expert=30924.
  2. Hypomagnesemia 1, intestinal. OMIM. 2016; https://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. https://www.nature.com/ejhg/journal/v22/n4/full/ejhg2013178a.html.