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TNNT3 gene
Reviewed by Medicinsk Expert•Last updated: 2026-10-22•Gene

TNNT3 gene

The TNNT3 gene provides instructions for making a protein essential for skeletal muscle contraction, and mutations in this gene are linked to Sheldon-Hall syndrome.

Normal Function

The TNNT3 gene provides instructions for making one form of a protein called troponin T. The troponin T protein produced from the TNNT3 gene is found in skeletal muscles, which are the muscles used for movement. Troponin T is one of three proteins that make up the troponin complex in muscle cells. The troponin complex, along with calcium, helps regulate muscle tensing (contraction).

The troponin complex is part of a structure called the sarcomere, which is the basic unit of muscle contraction. Sarcomeres contain thick and thin filaments. The overlapping thick and thin filaments attach (bind) to each other and release, which allows the filaments to move relative to one another so that muscles can contract.

When calcium levels are low, the troponin complex blocks the binding between the thick and thin filaments that is needed for muscle contraction. An increase in calcium levels causes structural changes in the troponin complex, which exposes the binding sites and allows the thick and thin filaments to interact, leading to muscle contraction.

Health Conditions Related to Genetic Changes

Sheldon-Hall syndrome

At least three TNNT3 gene mutations have been identified in people with Sheldon-Hall syndrome. This disorder affects muscle and skeletal development before birth and is characterized by joint deformities (contractures) that restrict movement in the hands and feet. The TNNT3 gene mutations that cause Sheldon-Hall syndrome may prevent the troponin complex from blocking thick and thin filament binding to control muscle contractions, resulting in the contractures and other muscle and skeletal abnormalities associated with Sheldon-Hall syndrome.

Other Names for This Gene

  • AMCD2B
  • beta TnTF
  • beta-TnTF
  • DA2B
  • DKFZp779M2348
  • fast skeletal muscle troponin T
  • FSSV
  • fTnT
  • TNTF
  • troponin T type 3 (skeletal, fast)
  • troponin T, fast skeletal muscle
  • troponin T, fast skeletal muscle isoform 1
  • troponin T, fast skeletal muscle isoform 2
  • troponin T, fast skeletal muscle isoform 3
  • troponin T, fast skeletal muscle isoform 4
  • troponin-T3, skeletal, fast

Frequently Asked Questions

Management of Sheldon-Hall syndrome focuses on maximizing joint mobility and overall function. This often includes intensive physical and occupational therapy, stretching exercises, and the use of serial casting or splints to gradually correct contractures. In some instances, surgical procedures may be necessary to release severe contractures and improve range of motion.
Sheldon-Hall syndrome caused by TNNT3 gene mutations is characterized by joint contractures, which are joints that are fixed in a bent or straightened position, limiting movement. These contractures are typically present at birth and most commonly affect the hands and feet, though other joints can also be involved. Affected individuals may also experience muscle weakness and other skeletal abnormalities.
Diagnosis of Sheldon-Hall syndrome is primarily based on the clinical observation of characteristic joint contractures at birth. To confirm the diagnosis and identify the specific genetic cause, genetic testing for mutations in the TNNT3 gene is performed. This involves analyzing a DNA sample, usually from blood, to detect known pathogenic variants.
Sheldon-Hall syndrome caused by TNNT3 mutations follows an autosomal dominant inheritance pattern. This means that if one parent has a TNNT3 gene mutation, there is a 50% chance with each pregnancy that their child will inherit the mutation and be affected by the syndrome. Genetic counseling is recommended for families to understand the risks and discuss reproductive options.
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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