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PROKR2 gene

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

PROKR2 gene

The PROKR2 gene provides instructions for making a receptor protein that is essential for the development of olfactory neurons and the regulation of reproductive hormones.

Normal Function

The PROKR2 gene provides instructions for making a protein called prokineticin receptor 2. This receptor interacts with a protein called prokineticin 2 (produced from the PROK2 gene). On the cell surface, prokineticin 2 attaches to the receptor like a key in a lock. When the two proteins are connected, they trigger a series of chemical signals within the cell that regulate various cell functions. Prokineticin 2 and its receptor are produced in many organs and tissues, including the small intestine, certain regions of the brain, and several hormone-producing (endocrine) tissues.

Prokineticin 2 and its receptor play a role in the development of a group of nerve cells that are specialized to process smells (olfactory neurons). These neurons move (migrate) from the developing nose to a structure in the front of the brain called the olfactory bulb, which is critical for the perception of odors. Prokineticin 2 and its receptor are also involved in the migration of nerve cells that produce gonadotropin-releasing hormone (GnRH). GnRH controls the production of several hormones that direct sexual development before birth and during puberty. These hormones are also important for the normal function of the ovaries in women and the testes in men.

Several additional functions of prokineticin 2 and its receptor have been discovered. These proteins help stimulate the movement of food through the intestine and are likely involved in the formation of new blood vessels (angiogenesis). They also play a role in coordinating daily (circadian) rhythms, such as the sleep-wake cycle and regular changes in body temperature. Prokineticin 2 and its receptor are active in a region of the brain called the suprachiasmatic nucleus (SCN), which acts as an internal clock that controls circadian rhythms.

Health Conditions Related to Genetic Changes

Kallmann syndrome

At least 30 mutations in the PROKR2 gene can cause Kallmann syndrome, a disorder characterized by the combination of hypogonadotropic hypogonadism (a condition affecting the production of hormones that direct sexual development) and an impaired sense of smell. Researchers estimate that mutations in the PROKR2 and PROK2 genes together account for about 9 percent of all cases of Kallmann syndrome.

Most of the PROKR2 gene mutations that cause Kallmann syndrome change single protein building blocks (amino acids) in prokineticin receptor 2. These mutations disrupt the function of the receptor, affecting its ability to trigger chemical signals within cells. A loss of this signaling disrupts the migration and survival of olfactory neurons and GnRH-producing neurons in the developing brain. If olfactory nerve cells do not extend to the olfactory bulb, a person's sense of smell will be impaired or absent. Misplacement or premature loss of GnRH-producing neurons prevents the production of sex hormones, which interferes with normal sexual development and causes puberty to be delayed or absent.

Other disorders

A few mutations in the PROKR2 gene have been identified in people with only one of the two major features of Kallmann syndrome:

  • Normosmic isolated hypogonadotropic hypogonadism (nIHH): Hypogonadotropic hypogonadism occurring with a normal ability to smell.
  • Isolated congenital anosmia (ICA): An impaired sense of smell without hypogonadotropic hypogonadism.

Like the PROKR2 gene mutations that cause Kallmann syndrome, the mutations associated with these conditions impair the function of prokineticin receptor 2, preventing it from transmitting signals properly. A loss of this signaling can disrupt the migration of GnRH-producing nerve cells or olfactory neurons in the developing brain.

Other Names for This Gene

  • G protein-coupled receptor 73-like 1
  • GPR73b
  • GPR73L1
  • GPRg2
  • KAL3
  • PK-R2
  • PKR2
  • PKR2_HUMAN

Frequently Asked Questions

Mutations in the PROKR2 gene can disrupt the migration of olfactory neurons from the nose to the olfactory bulb in the brain. This results in anosmia, which is the complete or partial loss of the sense of smell. Individuals with this condition often do not realize they have lost their sense of smell because the loss occurs during fetal development, so they have no memory of having a normal sense of smell.
Yes, because the PROKR2 receptor is essential for the migration of GnRH-producing neurons, mutations can lead to hypogonadotropic hypogonadism. This condition means the brain does not send the correct signals to the ovaries or testes to produce sex hormones, resulting in delayed or absent puberty, infertility, and low sex hormone levels.
PROKR2-related conditions are typically inherited in an autosomal recessive pattern. This means a person must inherit two mutated copies of the gene, one from each parent, to be affected. Parents who carry one mutated copy are usually carriers and do not show symptoms, but there is a 25 percent chance with each pregnancy that their child will inherit two mutated copies.
In addition to anosmia and hypogonadism, some individuals may experience gastrointestinal issues because the prokineticin 2 system helps regulate intestinal motility. There is also a potential link to circadian rhythm disturbances, which can affect sleep-wake cycles, though this symptom is less consistently reported than the primary reproductive and olfactory defects.
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.