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EFNB1 gene

ephrin B1

Normal Function

The EFNB1 gene provides instructions for making a protein called ephrin B1. This protein spans the membrane that surrounds the cell. The portion outside the cell attaches (binds) to proteins called Eph receptor kinases on the surface of neighboring cells. Together, these proteins form Eph/ephrin complexes, which help cells stick to one another (cell adhesion) and communicate. Communication between the attached cells plays a critical role in the normal shaping (patterning) of many tissues and organs before birth. In the brain, Eph/ephrin complexes also play a part in the development of nerve cells (neurons) and in the ability of the connections between neurons (synapses) to change and adapt over time in response to experience (synaptic plasticity).

Health Conditions Related to Genetic Changes

Craniofrontonasal syndrome

More than 115 mutations in the EFNB1 gene have been found to cause craniofrontonasal syndrome. This rare condition is characterized by the premature closure of certain bones of the skull (craniosynostosis) during development, which affects the shape of the head and face. Females with craniofrontonasal syndrome typically have more severe signs and symptoms than affected males, who often have one or two features of the condition.

Mutations in the EFNB1 gene result in a shortage (deficiency) of ephrin B1 protein. Most of these mutations lead to an abnormally short version of the molecule that acts as the genetic blueprint used to make the ephrin B1 protein. The shortened molecules are quickly broken down before protein can be produced. A deficiency of ephrin B1 protein prevents the adhesion and communication between cells that aids in proper development , which disrupts normal patterning in tissues before birth. Abnormal development of the skull and other facial structures leads to the signs and symptoms of craniofrontonasal syndrome.

More About This Health Condition

Other Names for This Gene

  • EFL3
  • EFNB1 gene
  • Elk-L
  • ELKL
  • EPLG2

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


  • Niethamer TK, Larson AR, O'Neill AK, Bershteyn M, Hsiao EC, Klein OD, Pomerantz JH, Bush JO. EPHRIN-B1 Mosaicism Drives Cell Segregation in Craniofrontonasal Syndrome hiPSC-Derived Neuroepithelial Cells. Stem Cell Reports. 2017 Mar 14;8(3):529-537. doi: 10.1016/j.stemcr.2017.01.017. Epub 2017 Feb 23. Citation on PubMed or Free article on PubMed Central
  • van den Elzen ME, Twigg SR, Goos JA, Hoogeboom AJ, van den Ouweland AM, Wilkie AO, Mathijssen IM. Phenotypes of craniofrontonasal syndrome in patients with a pathogenic mutation in EFNB1. Eur J Hum Genet. 2014 Aug;22(8):995-1001. doi: 10.1038/ejhg.2013.273. Epub 2013 Nov 27. Citation on PubMed or Free article on PubMed Central
  • Zhang RX, Han Y, Chen C, Xu LZ, Li JL, Chen N, Sun CY, Chen WH, Zhu WL, Shi J, Lu L. EphB2 in the Medial Prefrontal Cortex Regulates Vulnerability to Stress. Neuropsychopharmacology. 2016 Sep;41(10):2541-56. doi: 10.1038/npp.2016.58. Epub 2016 Apr 22. Erratum In: Neuropsychopharmacology. 2019 Jun;44(7):1339-1343. 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.