Hypomagnesemia with secondary hypocalcemia

Hypomagnesemia with secondary hypocalcemia (HSH) is a rare genetic disorder characterized by low levels of magnesium in the blood, which leads to secondary low levels of calcium (hypocalcemia). This condition is often detected in infancy and can present with severe symptoms if not treated promptly.

Causes

HSH is primarily caused by mutations in the TRPM6 gene, which plays a crucial role in magnesium absorption in the kidneys and intestines. The TRPM6 gene encodes for a channel that is essential for the proper transport of magnesium into the body's cells. When mutations occur in this gene, magnesium absorption is impaired, leading to hypomagnesemia. As magnesium is essential for the activation of the parathyroid hormone, its deficiency indirectly leads to hypocalcemia by affecting calcium regulation in the body.

Symptoms

The symptoms of HSH can vary but often include neuromuscular irritability, which manifests as tremors, seizures, and muscle spasms. Other symptoms may include lethargy, poor feeding, and developmental delays in infants. The severity of symptoms is directly related to the levels of magnesium and calcium in the blood.

Diagnosis

Diagnosis of HSH involves a thorough clinical evaluation and a series of laboratory tests. Blood tests are essential to measure the levels of magnesium and calcium. Genetic testing can confirm mutations in the TRPM6 gene, providing a definitive diagnosis.

Treatment

The primary treatment for HSH is magnesium supplementation, which can significantly alleviate symptoms and prevent complications. Oral magnesium salts are commonly used, but in cases of severe deficiency, intravenous magnesium may be necessary. Calcium supplementation may also be required to address hypocalcemia. Long-term management includes regular monitoring of magnesium and calcium levels and adjustments in supplementation as needed.

Prognosis

With early diagnosis and appropriate treatment, individuals with HSH can lead relatively normal lives. However, ongoing management is crucial to prevent potential complications associated with low magnesium and calcium levels.