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MED13L gene

mediator complex subunit 13L

Normal Function

The MED13L gene provides instructions for making a protein that is one piece (subunit) of a group of proteins known as the mediator complex. This complex regulates the activity (transcription) of genes. Transcription is the first step in the process by which information stored in a gene's DNA is used to build proteins.

The mediator complex physically links the proteins that can turn genes on, called transcription factors, with the enzyme that carries out transcription, called RNA polymerase II. Once transcription factors are attached to RNA polymerase II, transcription begins.

Researchers believe that as part of the mediator complex, the MED13L protein is involved in many aspects of early development, including development of the heart, nerve cells (neurons) in the brain, and structures in the face. The mediator complex plays a role in several chemical signaling pathways within cells. These pathways help direct a broad range of cellular activities, such as cell growth, cell movement (migration), and the process by which cells mature to carry out specific functions (differentiation).

Health Conditions Related to Genetic Changes

MED13L syndrome

More than 50 mutations in the MED13L gene have been found to cause MED13L syndrome. This condition is characterized by moderate to severe developmental delay and intellectual disability and minor differences in facial features. Additionally, some people with MED13L syndrome have recurrent seizures (epilepsy) or heart abnormalities that are present from birth (congenital heart defects).

Some MED13L gene mutations insert or delete regions of DNA within the MED13L gene. These genetic changes lead to a reduction in the total amount of MED13L protein in cells. Other mutations change single protein building blocks (amino acids) in the MED13L protein. It is thought that the altered protein interferes with the function of the normal protein produced from the non-mutated copy of the MED13L gene (such mutations are described as "dominant-negative"). Because dominant negative mutations impair the function of proteins made from both the altered copy of the MED13L gene and the normal copy, individuals with dominant negative mutations tend to have more severe signs than people with mutations that affect protein production from just the altered copy of the gene. While it is likely that mutations in the MED13L gene impair the control of gene activity by the mediator complex, it is unclear how these changes lead to the particular cognitive and physical features of the disorder.

More About This Health Condition

Critical congenital heart disease

MedlinePlus Genetics provides information about Critical congenital heart disease

More About This Health Condition

Other Names for This Gene

  • KIAA1025
  • PROSIT240
  • THRAP2
  • TRAP240L

Additional Information & Resources

Tests Listed in the Genetic Testing Registry

Scientific Articles on PubMed

Gene and Variant Databases


  • Asadollahi R, Oneda B, Sheth F, Azzarello-Burri S, Baldinger R, Joset P, Latal B, Knirsch W, Desai S, Baumer A, Houge G, Andrieux J, Rauch A. Dosage changes of MED13L further delineate its role in congenital heart defects and intellectual disability. Eur J Hum Genet. 2013 Oct;21(10):1100-4. doi: 10.1038/ejhg.2013.17. Epub 2013 Feb 13. Citation on PubMed or Free article on PubMed Central
  • Asadollahi R, Zweier M, Gogoll L, Schiffmann R, Sticht H, Steindl K, Rauch A. Genotype-phenotype evaluation of MED13L defects in the light of a novel truncating and a recurrent missense mutation. Eur J Med Genet. 2017 Sep;60(9):451-464. doi: 10.1016/j.ejmg.2017.06.004. Epub 2017 Jun 21. Citation on PubMed
  • Cafiero C, Marangi G, Orteschi D, Ali M, Asaro A, Ponzi E, Moncada A, Ricciardi S, Murdolo M, Mancano G, Contaldo I, Leuzzi V, Battaglia D, Mercuri E, Slavotinek AM, Zollino M. Novel de novo heterozygous loss-of-function variants in MED13L and further delineation of the MED13L haploinsufficiency syndrome. Eur J Hum Genet. 2015 Nov;23(11):1499-504. doi: 10.1038/ejhg.2015.19. Epub 2015 Feb 25. Citation on PubMed or Free article on PubMed Central
  • Smol T, Petit F, Piton A, Keren B, Sanlaville D, Afenjar A, Baker S, Bedoukian EC, Bhoj EJ, Bonneau D, Boudry-Labis E, Bouquillon S, Boute-Benejean O, Caumes R, Chatron N, Colson C, Coubes C, Coutton C, Devillard F, Dieux-Coeslier A, Doco-Fenzy M, Ewans LJ, Faivre L, Fassi E, Field M, Fournier C, Francannet C, Genevieve D, Giurgea I, Goldenberg A, Green AK, Guerrot AM, Heron D, Isidor B, Keena BA, Krock BL, Kuentz P, Lapi E, Le Meur N, Lesca G, Li D, Marey I, Mignot C, Nava C, Nesbitt A, Nicolas G, Roche-Lestienne C, Roscioli T, Satre V, Santani A, Stefanova M, Steinwall Larsen S, Saugier-Veber P, Picker-Minh S, Thuillier C, Verloes A, Vieville G, Wenzel M, Willems M, Whalen S, Zarate YA, Ziegler A, Manouvrier-Hanu S, Kalscheuer VM, Gerard B, Ghoumid J. MED13L-related intellectual disability: involvement of missense variants and delineation of the phenotype. Neurogenetics. 2018 May;19(2):93-103. doi: 10.1007/s10048-018-0541-0. Epub 2018 Mar 6. Citation on PubMed
  • van Haelst MM, Monroe GR, Duran K, van Binsbergen E, Breur JM, Giltay JC, van Haaften G. Further confirmation of the MED13L haploinsufficiency syndrome. Eur J Hum Genet. 2015 Jan;23(1):135-8. doi: 10.1038/ejhg.2014.69. Epub 2014 Apr 30. Citation on PubMed or Free article on PubMed Central

The information on this site should not be used as a substitute for professional medical care or advice. Contact a health care provider if you have questions about your health.