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Genetics Home Reference: your guide to understanding genetic conditions     A service of the U.S. National Library of Medicine®


Reviewed July 2009

What is the official name of the SEC23B gene?

The official name of this gene is “Sec23 homolog B (S. cerevisiae).”

SEC23B is the gene's official symbol. The SEC23B gene is also known by other names, listed below.

What is the normal function of the SEC23B gene?

The SEC23B gene provides instructions for making one component of a large group of interacting proteins called coat protein complex II (COPII). COPII is involved in the formation of vesicles, which are small sac-like structures that transport proteins and other materials within cells. Specifically, COPII triggers the formation of vesicles in a cellular structure called the endoplasmic reticulum (ER), which is involved in protein processing and transport. These COPII vesicles carry proteins that are destined to be exported out of cells (secreted).

The SEC23B protein is very similar to the protein produced from a related gene, SEC23A. These proteins are both components of COPII, and they appear to have overlapping functions. In most types of cells, if one of these proteins is missing, the other may be able to compensate for the loss. However, research indicates that the SEC23B protein may have a unique function in developing red blood cells (erythroblasts).

How are changes in the SEC23B gene related to health conditions?

congenital dyserythropoietic anemia - caused by mutations in the SEC23B gene

At least 20 mutations in the SEC23B gene have been identified in people with congenital dyserythropoietic anemia (CDA) type II. Most of these mutations change single protein building blocks (amino acids) in the SEC23B protein. Other mutations delete genetic material from the SEC23B gene or alter the way the gene's instructions are used to make the SEC23B protein. The mutations responsible for CDA type II likely disrupt the function of the SEC23B protein. However, researchers suspect that these mutations do not completely eliminate the function of the protein, which appears to be essential for life.

It is unclear how SEC23B mutations cause the characteristic features of CDA type II. The abnormal SEC23B protein leads to the production of erythroblasts that are unusually shaped and may have extra nuclei. These defective erythroblasts cannot develop into functional mature red blood cells. The resulting shortage of healthy red blood cells leads to the characteristic signs and symptoms of anemia, as well as complications including an enlarged liver and spleen (hepatosplenomegaly) and an abnormal buildup of iron that can damage the body's organs.

Where is the SEC23B gene located?

Cytogenetic Location: 20p11.23

Molecular Location on chromosome 20: base pairs 18,507,543 to 18,561,414

The SEC23B gene is located on the short (p) arm of chromosome 20 at position 11.23.

The SEC23B gene is located on the short (p) arm of chromosome 20 at position 11.23.

More precisely, the SEC23B gene is located from base pair 18,507,543 to base pair 18,561,414 on chromosome 20.

See How do geneticists indicate the location of a gene? ( in the Handbook.

Where can I find additional information about SEC23B?

You and your healthcare professional may find the following resources about SEC23B 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 SEC23B gene or gene products?

  • CDA-II
  • Sec23 homolog B
  • SEC23-like protein B
  • SEC23-related protein B
  • transport protein SEC23B

See How are genetic conditions and genes named? ( in the Handbook.

What glossary definitions help with understanding SEC23B?

acids ; anemia ; congenital ; endoplasmic reticulum ; ER ; erythropoiesis ; gene ; Golgi apparatus ; hepatosplenomegaly ; iron ; protein

You may find definitions for these and many other terms in the Genetics Home Reference Glossary (


  • Denecke J, Marquardt T. Congenital dyserythropoietic anemia type II (CDAII/HEMPAS): where are we now? Biochim Biophys Acta. 2009 Sep;1792(9):915-20. doi: 10.1016/j.bbadis.2008.12.005. Epub 2008 Dec 25. Review. (
  • Fromme JC, Orci L, Schekman R. Coordination of COPII vesicle trafficking by Sec23. Trends Cell Biol. 2008 Jul;18(7):330-6. doi: 10.1016/j.tcb.2008.04.006. Epub 2008 Jun 3. Review. (
  • Hughes H, Stephens DJ. Assembly, organization, and function of the COPII coat. Histochem Cell Biol. 2008 Feb;129(2):129-51. Epub 2007 Dec 4. Review. (
  • NCBI Gene (
  • Schwarz K, Iolascon A, Verissimo F, Trede NS, Horsley W, Chen W, Paw BH, Hopfner KP, Holzmann K, Russo R, Esposito MR, Spano D, De Falco L, Heinrich K, Joggerst B, Rojewski MT, Perrotta S, Denecke J, Pannicke U, Delaunay J, Pepperkok R, Heimpel H. Mutations affecting the secretory COPII coat component SEC23B cause congenital dyserythropoietic anemia type II. Nat Genet. 2009 Aug;41(8):936-40. doi: 10.1038/ng.405. Epub 2009 Jun 28. (


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? ( in the Handbook.

Reviewed: July 2009
Published: March 30, 2015