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Genetics Home Reference: your guide to understanding genetic conditions
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LDB3

Reviewed January 2011

What is the official name of the LDB3 gene?

The official name of this gene is “LIM domain binding 3.”

LDB3 is the gene's official symbol. The LDB3 gene is also known by other names, listed below.

What is the normal function of the LDB3 gene?

The LDB3 gene provides instructions for making a protein called LIM domain binding 3 (LDB3). The LDB3 protein is found in heart (cardiac) muscle and muscles used for movement (skeletal muscle). Within muscle fibers, LDB3 proteins are found in structures called sarcomeres, which are necessary for muscles to tense (contract). This protein attaches (binds) to other proteins and is involved in maintaining the stability of rod-like structures within sarcomeres called Z-discs. Z-discs link neighboring sarcomeres together to form myofibrils, the basic unit of muscle fibers. The linking of sarcomeres and formation of myofibrils provide strength for muscle fibers during repeated cycles of muscle contraction and relaxation.

Several different versions (isoforms) of the LDB3 protein are produced from the LDB3 gene.

How are changes in the LDB3 gene related to health conditions?

myofibrillar myopathy - caused by mutations in the LDB3 gene

At least three mutations in the LDB3 gene have been found to cause myofibrillar myopathy. These mutations change single protein building blocks (amino acids) in the LDB3 protein. Mutated LDB3 proteins cluster together with other muscle proteins in the sarcomere to form clumps (aggregates). The aggregates prevent these proteins from functioning normally. A dysfunctional desmin protein cannot properly interact with Z-discs, leading to abnormalities of sarcomere structure and problems with the formation of myofibrils. LDB3 gene mutations that cause myofibrillar myopathy impair the function of muscle fibers, causing weakness and the other features of this condition.

other disorders - caused by mutations in the LDB3 gene

Mutations in the LDB3 gene also cause a form of heart disease called dilated cardiomyopathy. This condition enlarges (dilates) and weakens the cardiac muscle, preventing it from pumping blood efficiently. Although cardiomyopathy is a sign of myofibrillar myopathy, some cases of dilated cardiomyopathy caused by LDB3 gene mutations are not associated with weakness of the skeletal muscles. Researchers have identified at least two mutations in the LDB3 gene that cause dilated cardiomyopathy without the other features of myofibrillar myopathy. These mutations, written as Asp117Asn and Lys136Met, change single amino acids in the LDB3 protein. Researchers are not certain why some mutations in the LDB3 gene cause dilated cardiomyopathy instead of myofibrillar myopathy.

Where is the LDB3 gene located?

Cytogenetic Location: 10q22.3-q23.2

Molecular Location on chromosome 10: base pairs 86,666,716 to 86,736,071

The LDB3 gene is located on the long (q) arm of chromosome 10 between positions 22.3 and 23.2.

The LDB3 gene is located on the long (q) arm of chromosome 10 between positions 22.3 and 23.2.

More precisely, the LDB3 gene is located from base pair 86,666,716 to base pair 86,736,071 on chromosome 10.

See How do geneticists indicate the location of a gene? (http://ghr.nlm.nih.gov/handbook/howgeneswork/genelocation) in the Handbook.

Where can I find additional information about LDB3?

You and your healthcare professional may find the following resources about LDB3 helpful.

You may also be interested in these resources, which are designed for genetics professionals and researchers.

What other names do people use for the LDB3 gene or gene products?

  • LDB3_HUMAN
  • LDB3Z1
  • LDB3Z4
  • LIM domain-binding protein 3
  • ZASP

See How are genetic conditions and genes named? (http://ghr.nlm.nih.gov/handbook/mutationsanddisorders/naming) in the Handbook.

What glossary definitions help with understanding LDB3?

acids ; cardiac ; cardiomyopathy ; contraction ; dilated ; domain ; familial ; gene ; isoforms ; myofibrils ; protein ; sarcomere ; sign ; skeletal muscle

You may find definitions for these and many other terms in the Genetics Home Reference Glossary (http://www.ghr.nlm.nih.gov/glossary).

References

  • Ferrer I, Olivé M. Molecular pathology of myofibrillar myopathies. Expert Rev Mol Med. 2008 Sep 3;10:e25. doi: 10.1017/S1462399408000793. Review. (http://www.ncbi.nlm.nih.gov/pubmed/18764962?dopt=Abstract)
  • OMIM: LIM DOMAIN-BINDING 3 (http://omim.org/entry/605906)
  • NCBI Gene (http://www.ncbi.nlm.nih.gov/gene/11155)
  • Schröder R, Schoser B. Myofibrillar myopathies: a clinical and myopathological guide. Brain Pathol. 2009 Jul;19(3):483-92. doi: 10.1111/j.1750-3639.2009.00289.x. Review. (http://www.ncbi.nlm.nih.gov/pubmed/19563540?dopt=Abstract)
  • Selcen D, Engel AG. Mutations in ZASP define a novel form of muscular dystrophy in humans. Ann Neurol. 2005 Feb;57(2):269-76. (http://www.ncbi.nlm.nih.gov/pubmed/15668942?dopt=Abstract)

 

The resources on this site should not be used as a substitute for professional medical care or advice. Users seeking information about a personal genetic disease, syndrome, or condition should consult with a qualified healthcare professional. See How can I find a genetics professional in my area? (http://ghr.nlm.nih.gov/handbook/consult/findingprofessional) in the Handbook.

 
Reviewed: January 2011
Published: September 15, 2014