Hypomagnesemia with secondary hypocalcemia (HSH)

Also known as

  • TRPM6 gene mutation Magnesium ion cannelloni defect

Where magnesium is not absorbed correctly due to a gene affecting the kidneys/intestines or colon. This causes hypomagnesemia and secondary hypocalcemia, which causes seizures in infancy. It not caught it can be fatal or lead to neurological damage.

Condition details

A very rare condition. The channels in the kidney which fluid passes through does not absorb magnesium enough or is defective. The same can also be happening to the channel in the colon when magnesium should be reobsorbed before fluid leeaces the body. High levels of magnesium supplements and a high magnesium diet is required life long. Other medication may be required

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Photos of affected individuals

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Typical age range of first manifestation

  • Can manifest in Baby
  • Does not manifest in Toddler
  • Does not manifest in Child 4-10
  • Does not manifest in Child 10-18
  • Does not manifest in Adult


Lay terms Clinical terms
  • Seizures Tetany Muscle spasms
  • Seizures Tetany

Affected genes identified to date

  • Trpm6

Inheritance patterns

Is Autosomal recessive

Are carriers affected?


How many are affected?

Unsure very rare

Support groups and organisations

No groups found

Known experts

Dr Shaw
Field of interest
Birmingham Childrens Hospital
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