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The official name of this gene is “roundabout, axon guidance receptor, homolog 3 (Drosophila).”
ROBO3 is the gene's official symbol. The ROBO3 gene is also known by other names, listed below.
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.
The ROBO3 gene belongs to a family of genes called fibronectin type III domain containing (fibronectin type III domain containing). It also belongs to a family of genes called immunoglobulin superfamily, immunoglobulin-like domain containing (immunoglobulin superfamily, immunoglobulin-like domain containing). It also belongs to a family of genes called immunoglobulin superfamily, I-set domain containing (immunoglobulin superfamily, I-set domain containing).
A gene family is a group of genes that share important characteristics. Classifying individual genes into families helps researchers describe how genes are related to each other. For more information, see What are gene families? (http://ghr.nlm.nih.gov/handbook/howgeneswork/genefamilies) in the Handbook.
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.
Cytogenetic Location: 11q24.2
Molecular Location on chromosome 11: base pairs 124,865,005 to 124,881,473
The ROBO3 gene is located on the long (q) arm of chromosome 11 at position 24.2.
More precisely, the ROBO3 gene is located from base pair 124,865,005 to base pair 124,881,473 on chromosome 11.
See How do geneticists indicate the location of a gene? (http://ghr.nlm.nih.gov/handbook/howgeneswork/genelocation) in the Handbook.
You and your healthcare professional may find the following resources about ROBO3 helpful.
You may also be interested in these resources, which are designed for genetics professionals and researchers.
See How are genetic conditions and genes named? (http://ghr.nlm.nih.gov/handbook/mutationsanddisorders/naming) in the Handbook.
axons ; brainstem ; crossing over ; gene ; motor ; nervous system ; neuronal migration ; palsy ; protein ; receptor ; scoliosis ; voluntary muscle
You may find definitions for these and many other terms in the Genetics Home Reference Glossary (http://ghr.nlm.nih.gov/glossary).
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? (http://ghr.nlm.nih.gov/handbook/consult/findingprofessional) in the Handbook.