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GCM2 gene
Reviewed by Medicinsk Expert•Last updated: 2026-10-22•Gene

GCM2 gene

The GCM2 gene provides instructions for a protein that is essential for the development and maintenance of the parathyroid glands and the regulation of blood calcium levels.

Normal Function

The GCM2 gene provides instructions for making a protein that is primarily found in the parathyroid glands. These four glands are located in the neck and produce a hormone called parathyroid hormone that regulates the levels of calcium in the blood. The GCM2 protein is needed for the development of the parathyroid glands before birth, and it plays a role in the maintenance of these glands into adulthood.

The GCM2 protein acts as a transcription factor, which means that it binds to specific regions of DNA and helps control the activity of genes. As a transcription factor, it is likely that the GCM2 protein helps produce parathyroid hormone.

Health Conditions Related to Genetic Changes

Familial isolated hyperparathyroidism

Variants (also called mutations) in the GCM2 gene can increase the risk of developing familial isolated hyperparathyroidism, a condition that is characterized by overactive parathyroid glands (hyperparathyroidism). These four glands are located in the neck and release a hormone that helps regulate the levels of calcium in the blood. This regulation is disrupted in people with familial isolated hyperparathyroidism, which can lead to high blood calcium levels (hypercalcemia), kidney stones, thinning of the bones (osteoporosis), nausea, vomiting, high blood pressure (hypertension), weakness, and fatigue.

Most of the GCM2 gene variants that are associated with familial isolated hyperparathyroidism lead to the substitution of one protein building block (amino acid) for another in the GCM2 protein. These changes cause cells to produce an overactive version of the GCM2 protein that likely leads to the overproduction of parathyroid hormone. As a result, more calcium could be released into the blood, causing people to have an increased risk of developing the signs and symptoms of familial isolated hyperparathyroidism.

Other disorders

Variants in the GCM2 gene can also cause isolated hypoparathyroidism, a condition that is characterized by a shortage of parathyroid hormone. People with isolated hypoparathyroidism often have low levels of calcium in the blood (hypocalcemia). Hypocalcemia can cause muscle cramping and other health problems, although many people with this condition have no associated health problems.

Most of the GCM2 gene variants that cause isolated hypoparathyroidism cause cells to produce an altered or abnormally shortened version of the GCM2 protein that does not function properly. As a result, the parathyroid glands produce less parathyroid hormone. Without enough parathyroid hormone, blood levels of calcium are kept low, leading to the signs and symptoms of isolated hypoparathyroidism.

Other Names for This Gene

  • GCMB

Frequently Asked Questions

Early symptoms are often subtle and can be mistaken for other conditions. Patients frequently report persistent fatigue, muscle weakness, and unexplained nausea or vomiting. As calcium levels rise, individuals may also experience increased thirst, frequent urination, and constipation. In some cases, the first noticeable sign is the formation of kidney stones or a diagnosis of osteoporosis during routine bone density testing.
Familial isolated hyperparathyroidism associated with GCM2 variants is inherited in an autosomal dominant pattern. This means that a change in just one copy of the gene in each cell is sufficient to increase the risk of developing the condition. An affected individual has a 50 percent chance of passing the variant to each of their children, regardless of sex.
The GCM2 protein acts as a transcription factor that controls the activity of genes in parathyroid cells. Variants associated with familial isolated hyperparathyroidism typically result in an overactive version of this protein. This overactivity causes the parathyroid glands to produce and release excessive amounts of parathyroid hormone, which in turn forces the body to pull calcium from the bones and retain it in the blood, leading to hypercalcemia.
Diagnosis typically begins with blood tests to measure calcium and parathyroid hormone levels, which will show elevated values in affected individuals. To confirm the genetic cause, clinicians order genetic testing for the GCM2 gene. This usually involves sequencing the gene to identify specific amino acid substitutions. In some cases, if the genetic test is negative but clinical suspicion remains high, further functional studies or evaluation of other parathyroid-related genes may be recommended.
Source: MedlinePlus, National Library of Medicine

MedlinePlus brings together authoritative health information from the National Library of Medicine (NLM), the National Institutes of Health (NIH), and other government agencies and health-related organizations.

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