The ROBO3 gene provides instructions for making a protein that is critical for the normal development of the nervous system. The protein is active in the developing spinal cord and in the brainstem, a region that connects the upper parts of the brain with the spinal cord. In the brainstem, the ROBO3 protein helps direct nerve cells (neurons) to their proper positions in a process called neuronal migration. The protein also helps guide the growth of axons, which are specialized extensions of neurons that transmit nerve impulses throughout the nervous system. Some axons are very long, connecting neurons in the brain with those in the spinal cord and elsewhere in the body.
For the brain and body to communicate effectively, certain bundles of axons must cross from one side of the body to the other in the brainstem. These include axons of motor neurons, which transmit information about voluntary muscle movement, and axons of sensory neurons, which transmit information about sensory input (such as touch, pain, and temperature). The ROBO3 protein plays a critical role in ensuring that this crossing over occurs during brain development.
Health Conditions Related to Genetic Changes
Horizontal gaze palsy with progressive scoliosis
At least 19 different mutations in the ROBO3 gene have been identified in people with horizontal gaze palsy with progressive scoliosis (HGPPS). These mutations change the structure of the ROBO3 protein in different ways; however, all of the mutations appear to result in a nonfunctional protein. A lack of functional ROBO3 protein disrupts normal brainstem development.
In people with HGPPS, the axons of motor and sensory neurons do not cross over in the brainstem, but stay on the same side of the body. Researchers believe that this miswiring is the underlying cause of the eye movement abnormalities associated with the disorder. The cause of progressive scoliosis in HGPPS is unclear. Researchers are working to determine why the effects of ROBO3 mutations appear to be limited to horizontal eye movement and scoliosis.More About This Health Condition
Other Names for This Gene
- retinoblastoma inhibiting gene 1
- Roundabout homolog 3
- roundabout, axon guidance receptor, homolog 3
- roundabout, axon guidance receptor, homolog 3 (Drosophila)
- Roundabout-like protein 3
Additional Information & Resources
Tests Listed in the Genetic Testing Registry
Scientific Articles on PubMed
Catalog of Genes and Diseases from OMIM
- Abu-Amero KK, al Dhalaan H, al Zayed Z, Hellani A, Bosley TM. Five new consanguineous families with horizontal gaze palsy and progressive scoliosis and novel ROBO3 mutations. J Neurol Sci. 2009 Jan 15;276(1-2):22-6. doi: 10.1016/j.jns.2008.08.026. Epub 2008 Oct 1. Citation on PubMed
- Amoiridis G, Tzagournissakis M, Christodoulou P, Karampekios S, Latsoudis H, Panou T, Simos P, Plaitakis A. Patients with horizontal gaze palsy and progressive scoliosis due to ROBO3 E319K mutation have both uncrossed and crossed central nervous system pathways and perform normally on neuropsychological testing. J Neurol Neurosurg Psychiatry. 2006 Sep;77(9):1047-53. Epub 2006 Jun 13. Citation on PubMed or Free article on PubMed Central
- Chan WM, Traboulsi EI, Arthur B, Friedman N, Andrews C, Engle EC. Horizontal gaze palsy with progressive scoliosis can result from compound heterozygous mutations in ROBO3. J Med Genet. 2006 Mar;43(3):e11. Citation on PubMed or Free article on PubMed Central
- Jen JC, Chan WM, Bosley TM, Wan J, Carr JR, Rüb U, Shattuck D, Salamon G, Kudo LC, Ou J, Lin DD, Salih MA, Kansu T, Al Dhalaan H, Al Zayed Z, MacDonald DB, Stigsby B, Plaitakis A, Dretakis EK, Gottlob I, Pieh C, Traboulsi EI, Wang Q, Wang L, Andrews C, Yamada K, Demer JL, Karim S, Alger JR, Geschwind DH, Deller T, Sicotte NL, Nelson SF, Baloh RW, Engle EC. Mutations in a human ROBO gene disrupt hindbrain axon pathway crossing and morphogenesis. Science. 2004 Jun 4;304(5676):1509-13. Epub 2004 Apr 22. Citation on PubMed or Free article on PubMed Central
- Jen JC. Effects of failure of development of crossing brainstem pathways on ocular motor control. Prog Brain Res. 2008;171:137-41. doi: 10.1016/S0079-6123(08)00618-3. Citation on PubMed