Doctors discovered a new genetic mutation that prevents babies from absorbing enough magnesium and calcium from food, which can cause dangerous seizures. A baby born to parents who were related (a risk factor for rare genetic diseases) had repeated seizures and was found to have very low levels of these important minerals in their blood. Genetic testing revealed a never-before-seen mutation in the TRPM6 gene, which controls how the intestines absorb magnesium. With proper treatment using magnesium and calcium supplements, the baby recovered well and developed normally. This case helps doctors understand this rare condition better and shows how genetic testing can identify the root cause of mysterious health problems in infants.

The Quick Take

  • What they studied: A rare genetic condition where babies cannot properly absorb magnesium and calcium from their intestines, leading to dangerously low levels of these minerals in the blood and seizures.
  • Who participated: One infant born to parents who were cousins (consanguineous marriage), which increases the chance of inheriting rare genetic conditions from both parents.
  • Key finding: Doctors identified a brand-new genetic mutation in the TRPM6 gene that was responsible for the baby’s condition. The mutation was inherited from both parents, who each carried one copy of the faulty gene.
  • What it means for you: If your baby has unexplained seizures and low calcium levels, genetic testing may reveal a treatable cause. This discovery helps doctors recognize and treat this rare condition earlier, potentially preventing serious complications.

The Research Details

This is a case report, which means doctors documented the medical history and treatment of one specific patient. The baby presented with multiple seizures and was admitted to the hospital for testing. Doctors performed blood tests that showed low calcium and magnesium levels, which was unusual because vitamin D and parathyroid hormone levels were normal—this pattern suggested a problem with how the intestines were absorbing minerals rather than a problem with the hormones that control mineral balance.

To find the cause, doctors used exome sequencing, a genetic test that reads the instructions in DNA to look for mutations. They found a deletion mutation in the TRPM6 gene, meaning a tiny piece of genetic code was missing. The parents were tested and found to carry one copy of this same mutation each, confirming this was an inherited genetic condition.

The baby was treated with intravenous (IV) magnesium and calcium to quickly raise levels, then switched to high-dose oral supplements. Follow-up visits showed the baby remained seizure-free and developed normally.

Case reports are important for identifying new diseases and mutations that doctors haven’t seen before. By documenting this novel mutation, doctors can now recognize similar cases in other patients and know how to treat them effectively. This helps build medical knowledge about rare genetic conditions.

This is a single case report, so the findings apply specifically to this one patient and cannot be generalized to all people with similar symptoms. However, the genetic analysis was thorough and the mutation was confirmed in both parents using Sanger sequencing, a gold-standard genetic test. The computer analysis of the mutation showed it would likely damage the protein’s function. The successful treatment and normal development provide strong evidence that the mutation was indeed the cause of the condition.

What the Results Show

The baby presented with multiple seizures in infancy, which prompted hospital admission and testing. Blood tests revealed severely low magnesium levels (hypomagnesaemia) and moderate to severe low calcium levels (hypocalcaemia). Interestingly, vitamin D and parathyroid hormone levels were normal, which was a crucial clue that the problem was with mineral absorption in the intestines rather than with the hormones that regulate minerals.

Genetic testing identified a novel homozygous in-frame deletion mutation in the TRPM6 gene (c.1550_1552delTAG, p.(Val517del)). This means the baby inherited the same faulty gene from both parents. The TRPM6 gene produces a protein that acts like a channel in intestinal cells, allowing magnesium to be absorbed from food. The deletion disrupts this channel’s function.

The fractional excretion of magnesium was 2.1%, a very low number that confirmed the intestines were not absorbing magnesium properly. This measurement helped doctors pinpoint the intestines as the problem source.

With treatment using intravenous magnesium and calcium followed by high-dose oral supplements, the baby’s mineral levels normalized. At follow-up, the baby remained seizure-free and showed normal development for their age, indicating successful treatment and good long-term outcomes.

The genetic analysis using computer modeling (in silico analysis) and protein structure prediction showed that the deletion mutation would be harmful to the TRPM6 protein’s function. This computational evidence supported the conclusion that the mutation was the actual cause of the condition. The fact that both parents carried one copy of the mutation but were healthy shows that you need to inherit the faulty gene from both parents for the disease to develop.

Hypomagnesaemia with secondary hypocalcaemia caused by TRPM6 mutations is a recognized but very rare genetic disorder. This case report adds to the medical literature by identifying a previously unknown mutation in the TRPM6 gene. The clinical presentation (seizures, low magnesium and calcium, normal vitamin D and parathyroid hormone) matches the known pattern of this condition, but the specific genetic mutation is novel, expanding doctors’ understanding of how different mutations in this gene can cause disease.

This is a single case report involving one patient, so the findings cannot be applied broadly to other people. The long-term follow-up period is not specified in detail, so we don’t know how long the baby was monitored after discharge. Additionally, this case involves consanguineous parents (related by blood), which is a specific risk factor for rare genetic conditions and may not apply to the general population. The study does not compare treatment outcomes to other patients with the same condition, as this is the first reported case of this particular mutation.

The Bottom Line

For parents and caregivers: If an infant has unexplained seizures combined with low calcium levels on blood tests, ask your doctor about testing for magnesium deficiency and genetic causes. For healthcare providers: Consider TRPM6 gene mutations in infants presenting with seizures, hypomagnesaemia, and secondary hypocalcaemia, especially when vitamin D and parathyroid hormone are normal. Genetic testing may identify treatable causes. High-dose magnesium and calcium supplementation appears effective for managing this condition. Confidence level: Moderate (based on one case, but with strong genetic and clinical evidence).

Parents of infants with unexplained seizures and abnormal mineral levels should discuss this condition with their pediatrician. Healthcare providers caring for infants with seizure disorders should be aware of this rare genetic cause. Genetic counselors may use this information when advising families with consanguineous relationships about genetic risks. This condition is so rare that most people will not be affected, but early recognition and treatment can prevent serious complications.

In this case, the baby showed improvement with treatment within the hospital stay and remained seizure-free at follow-up. However, this is a single case, so the typical timeline for other patients may vary. Long-term management with ongoing supplementation appears necessary to maintain normal mineral levels.

Want to Apply This Research?

  • If you have a family history of this condition or have been diagnosed, track serum magnesium and calcium levels monthly (or as recommended by your doctor) using a simple chart that records the date, test results, and any symptoms like muscle twitches or weakness.
  • Set daily reminders to take magnesium and calcium supplements at the same time each day. Use the app to log supplement intake and note any side effects like stomach upset. This helps ensure consistent treatment and makes it easy to discuss adherence with your healthcare provider.
  • Create a long-term tracking system that records mineral levels from lab tests every 3-6 months, any seizure activity or neurological symptoms, medication doses and changes, and dietary intake of magnesium-rich foods. Share this data with your healthcare team to optimize treatment and catch any problems early.

This case report describes a single patient with a rare genetic condition and should not be used for self-diagnosis. If you or your child experiences unexplained seizures or has been found to have low magnesium or calcium levels, consult with a qualified healthcare provider or pediatrician for proper evaluation and treatment. Genetic testing and diagnosis should only be performed by qualified medical professionals. The information presented is for educational purposes and does not replace professional medical advice. Always discuss any concerns about mineral deficiencies or seizure disorders with your doctor before starting any supplements or treatments.