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

TSHB gene

The TSHB gene provides instructions for the beta subunit of thyroid stimulating hormone, which is essential for regulating thyroid gland growth and hormone production.

Normal Function

The TSHB gene provides instructions for one piece (subunit) of a hormone called thyroid stimulating hormone (TSH). Thyroid stimulating hormone consists of two subunits called alpha and beta. The TSHB gene provides instructions for making the beta subunit. The alpha and beta subunits are bound together to produce the active form of the hormone. A particular segment of the beta subunit, known as the buckle or seatbelt, wraps around the alpha subunit to form the active hormone. This seatbelt region also helps stabilize the hormone's structure.

Thyroid stimulating hormone is made in the pituitary gland, a gland at the base of the brain. This hormone plays an important role in the growth and function of the thyroid gland. It also stimulates the production of thyroid hormones, which play a critical role in regulating growth, brain development, and the rate of chemical reactions in the body (metabolism). The pituitary gland monitors levels of thyroid hormones; when levels are too low, the pituitary gland releases thyroid stimulating hormone into the bloodstream to signal increased thyroid gland growth and hormone production.

Health Conditions Related to Genetic Changes

Congenital hypothyroidism

Researchers have identified at least 10 TSHB gene mutations involved in congenital hypothyroidism, a condition characterized by abnormally low levels of thyroid hormones starting from birth. TSHB gene mutations are the primary cause of a form of the condition called central congenital hypothyroidism, which occurs when stimulation of thyroid hormone production by the pituitary gland is impaired.

TSHB gene mutations involved in congenital hypothyroidism alter the size or shape of the thyroid stimulating hormone beta subunit:

  • Many mutations affect the beta subunit's seatbelt region.
  • Some mutations severely shorten the beta subunit, eliminating the seatbelt region partially or entirely.
  • Other mutations change the protein building blocks (amino acids) used to make the beta subunit.

As a result, the seatbelt region cannot buckle around the alpha subunit. TSHB gene mutations prevent the production of functional thyroid stimulating hormone or its release (secretion) from the pituitary gland. Consequently, thyroid hormone production is not stimulated, leading to low hormone levels. Additionally, the thyroid gland is reduced in size (hypoplastic) because its growth is not stimulated.

Other Names for This Gene

  • thyroid stimulating hormone, beta
  • thyrotropin beta chain precursor
  • thyrotropin beta subunit
  • TSH-BETA
  • TSHB_HUMAN

Frequently Asked Questions

Central congenital hypothyroidism (CCH) differs because the problem originates in the pituitary gland (at the base of the brain), which fails to produce enough thyroid stimulating hormone (TSH). In other forms, the thyroid gland itself is the primary issue. With TSHB mutations, the pituitary cannot make a functional TSH, leading to insufficient stimulation of the thyroid gland and low thyroid hormone levels from birth.
Diagnosis typically begins with newborn screening, which may show low thyroid hormone levels (T4) but TSH levels that are not as high as seen in primary hypothyroidism, or even low/normal TSH levels. Genetic testing for TSHB mutations can confirm the diagnosis. Treatment involves lifelong daily oral thyroid hormone replacement therapy (levothyroxine) to ensure normal growth and brain development.
Similar to other forms of congenital hypothyroidism, newborns with CCH often have very subtle or no symptoms at birth. If present, signs might include prolonged jaundice, poor feeding, lethargy, constipation, or a hoarse cry. Because the pituitary gland is affected, other pituitary hormone deficiencies might also be present, though this is not always the case with isolated TSHB mutations. Early detection through newborn screening is crucial.
Yes, central congenital hypothyroidism caused by TSHB gene mutations is an inherited condition. It is typically passed down in an autosomal recessive pattern, meaning a child must inherit two copies of the mutated TSHB gene (one from each parent) to develop the condition. Parents who are carriers usually do not have symptoms but have a 25% chance of having an affected child with each pregnancy. Genetic counseling can provide specific risk assessments.
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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