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TRAPPC2 gene

trafficking protein particle complex subunit 2

Normal Function

The TRAPPC2 gene provides instructions for producing the protein sedlin, which is found in cells throughout the body. Sedlin is part of a large group of proteins called the trafficking protein particle (TRAPP) complex, which plays a role in the transport of proteins between cell compartments (organelles). Sedlin is thought to be located between two organelles, the endoplasmic reticulum and the Golgi apparatus. The endoplasmic reticulum is involved in protein processing and transport, and the Golgi apparatus modifies newly produced proteins.

Research shows that sedlin is required for transporting large proteins from the endoplasmic reticulum to the Golgi apparatus. For example, sedlin is needed to move large molecules called procollagens out of the endoplasmic reticulum so they can be processed further by the Golgi apparatus. Later, procollagens are altered by enzymes outside the cell to create smaller mature collagen proteins, which strengthen and support connective tissues, such as skin, bone, cartilage, tendons, and ligaments.

Health Conditions Related to Genetic Changes

X-linked spondyloepiphyseal dysplasia tarda

More than 50 mutations in the TRAPPC2 gene have been found to cause X-linked spondyloepiphyseal dysplasia tarda. This condition impairs bone growth and occurs almost exclusively in males, usually appearing between ages 6 and 10. Almost all mutations result in a nonfunctional sedlin protein. As a result, large proteins, including procollagen, cannot be transported out of the endoplasmic reticulum. A lack of procollagen transport reduces the amount of mature collagen in cells, which impairs the development of bones, cartilage, and other connective tissues. It is likely that this disruption in bone development leads to many of the signs and symptoms of X-linked spondyloepiphyseal dysplasia tarda, although it is unclear why the skeletal problems do not appear until later in childhood.

More About This Health Condition

Other Names for This Gene

  • MBP-1 interacting protein-2A
  • MIP-2A
  • SEDL
  • sedlin
  • SEDT
  • TRS20
  • ZNF547L

Additional Information & Resources

Tests Listed in the Genetic Testing Registry

Scientific Articles on PubMed

Catalog of Genes and Diseases from OMIM

Gene and Variant Databases


  • Mumm S, Zhang X, Vacca M, D'Esposito M, Whyte MP. The sedlin gene for spondyloepiphyseal dysplasia tarda escapes X-inactivation and contains a non-canonical splice site. Gene. 2001 Aug 8;273(2):285-93. doi: 10.1016/s0378-1119(01)00571-6. Citation on PubMed
  • Venditti R, Scanu T, Santoro M, Di Tullio G, Spaar A, Gaibisso R, Beznoussenko GV, Mironov AA, Mironov A Jr, Zelante L, Piemontese MR, Notarangelo A, Malhotra V, Vertel BM, Wilson C, De Matteis MA. Sedlin controls the ER export of procollagen by regulating the Sar1 cycle. Science. 2012 Sep 28;337(6102):1668-72. doi: 10.1126/science.1224947. Citation on PubMed or Free article on PubMed Central
  • Wang H, Wu W, Xu Z, Xie J. A novel splicing mutation in the SEDL gene causes spondyloepiphyseal dysplasia tarda in a large Chinese pedigree. Clin Chim Acta. 2013 Oct 21;425:30-3. doi: 10.1016/j.cca.2013.07.002. Epub 2013 Jul 19. Citation on PubMed
  • Xia XY, Yu J, Li WW, Li N, Wu QY, Zhou X, Cui YX, Li XJ. A novel nonsense mutation in the sedlin gene (SEDL) causes severe spondyloepiphyseal dysplasia tarda in a five-generation Chinese pedigree. Genet Mol Res. 2014 Apr 29;13(2):3362-70. doi: 10.4238/2014.April.29.15. Citation on PubMed

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.