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NRAS
NRAS proto-oncogene, GTPase
The NRAS gene provides instructions for a protein called N-Ras, central to regulating cell division, differentiation, and relaying signals within cells. The NRAS gene encodes the N-Ras protein, a GTPase crucial for signal transduction pathways that govern cell growth and specialisation.
NRAS is located on the short (p) arm of chromosome 1, at band 1p13.2. Arm ratio per GRCh38 - banding schematic.
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Overview
The NRAS gene, also known as NRAS proto-oncogene, GTPase, is a member of the Ras family of oncogenes. It provides genetic instructions for producing the N-Ras protein, which functions as a molecular switch in vital cellular signalling pathways.
This gene plays a fundamental role in regulating cell proliferation, differentiation, and programmed cell death (apoptosis). Its involvement in relaying signals from the cell's exterior to its nucleus is critical for proper cellular function and development.
What the gene does
The N-Ras protein, encoded by the NRAS gene, is a GTPase, meaning it can convert guanosine triphosphate (GTP) into guanosine diphosphate (GDP). This enzymatic activity is essential for its function as a molecular switch in signal transduction. The protein relays signals from outside the cell to the nucleus, influencing processes such as cell growth and division (proliferation) or maturation into specialised forms (differentiation).
When N-Ras is bound to GTP, it is in an 'on' state and actively transmits signals. Conversely, a change to GDP inactivates the protein, ceasing signal transmission. This intricate on-off mechanism ensures precise control over cellular responses. As an oncogene, specific changes in NRAS can lead to uncontrolled cell growth, highlighting its importance in maintaining cellular homeostasis and preventing disease.
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Chromosome location
The NRAS gene is situated on the short (p) arm of chromosome 1, at position 13.2, which can be denoted as 1p13.2. This genomic location means the gene is found relatively close to the centromere on the shorter arm of chromosome 1. The precise positioning of NRAS is consistently found at 1p13.2 across the human genome.
Protein structure
The N-Ras protein consists of 189 amino acids and includes distinct functional regions critical for its activity. A key component is the Effector region, encompassing amino acids 32-40, which is vital for interacting with downstream signalling molecules. Additionally, the protein features a Hypervariable region, located between amino acids 166-185, which contributes to its membrane localisation and regulatory properties within the cell.
Key variants
Variants within the NRAS gene can alter the protein's usual function, potentially disrupting cellular signalling pathways that regulate growth and division. These genetic changes can affect the protein's ability to act as a molecular switch, leading to its persistent activation or inactivation. Genetic changes in NRAS are typically somatic, meaning they are acquired during an individual's lifetime rather than inherited. Such variants may contribute to a range of conditions, especially those involving abnormal cell proliferation or development.
Sample of pathogenic variants
10 pathogenic / likely-pathogenic variants from ClinVar, ranked by review status (expert-panel-reviewed first). This is a sample; recurrent founder variants in a specific population may not appear here - see the full ClinVar listing via the link above.
| Variant (HGVS) | Protein change | Classification | Evidence | Associated condition |
|---|---|---|---|---|
c.149C>T | p.Thr50Ile | Pathogenic | ★★★☆ | RASopathy |
c.173C>T | p.Thr58Ile | Pathogenic | ★★★☆ | Noonan syndrome |
c.179G>A | p.Gly60Glu | Pathogenic | ★★★☆ | RASopathy |
c.34G>A | p.Gly12Ser | Pathogenic | ★★★☆ | RASopathy |
c.175G>A | p.Ala59Thr | Pathogenic/Likely pathogenic | ★★☆☆ | Noonan syndrome 6 |
c.182A>G | p.Gln61Arg | Pathogenic | ★★☆☆ | Thyroid cancer, nonmedullary, 2 |
c.34G>C | p.Gly12Arg | Pathogenic | ★★☆☆ | NRAS-related disorder |
c.34G>T | p.Gly12Cys | Pathogenic | ★★☆☆ | NRAS-related disorder |
c.35G>A | p.Gly12Asp | Pathogenic/Likely pathogenic | ★★☆☆ | NRAS-related disorder |
c.35G>C | p.Gly12Ala | Pathogenic/Likely pathogenic | ★★☆☆ | Noonan syndrome and Noonan-related syndrome |
Evidence stars indicate ClinVar review status. Individual variant interpretation should always be performed by a qualified clinical laboratory - many variants remain classified as Variants of Uncertain Significance (VUS) pending more research.
Associated conditions
Changes in the NRAS gene are associated with several conditions, often due to somatic variants that arise after conception. Notably, NRAS variants can be implicated in Congenital melanocytic naevus (giant), a condition characterised by large moles present at birth. Another condition linked to NRAS is Kaposiform lymphangiomatosis, an uncommon vascular disorder.
UK clinical status
The NRAS gene is recognised within the UK's NHS Genomic Medicine Service due to its clinical significance and is included on several PanelApp panels. These include 'Adult solid tumours cancer susceptibility', 'Childhood solid tumours cancer susceptibility', 'DDG2P', 'Foetal anomalies', 'Foetal hydrops', 'Intellectual disability', 'IUGR and IGF abnormalities', 'Monogenic short stature', 'Mosaic skin disorders - deep sequencing', 'Paediatric or syndromic cardiomyopathy', 'Pigmentary skin disorders', 'Primary lymphoedema', and 'RASopathies', all of which are categorised as 'green' indicating they are routinely covered.
Sources: NHS GMS PanelApp · Genomics England PanelApp · NHS National Genomic Test Directory
Diet & lifestyle considerations
Research suggests that generally maintaining a healthy lifestyle, including a balanced diet and regular physical activity, supports overall cellular health. While specific lifestyle interventions are not directly linked to preventing NRAS-related conditions, these general health practices contribute to well-being. Avoiding excessive sun exposure, for example, is a common recommendation for general skin health, particularly for individuals with certain skin conditions.
Supplement considerations
There is currently no conclusive scientific evidence to suggest that specific dietary supplements can prevent or treat conditions associated with NRAS variants. Individuals considering supplements should consult a healthcare provider to discuss potential risks and benefits, as some supplements may interact with medications or existing health conditions.
Frequently asked questions
What is the primary function of the NRAS gene?
The NRAS gene provides instructions for the N-Ras protein, a GTPase that acts as a molecular switch in cell signalling pathways, regulating cell division, differentiation, and programmed cell death.
How does the N-Ras protein work as a 'molecular switch'?
The N-Ras protein functions by binding to either GTP or GDP. When bound to GTP, it is 'on' and transmits signals; when it converts GTP to GDP, it becomes 'off' and ceases signal transmission.
Are conditions linked to NRAS variants typically inherited?
Conditions associated with NRAS variants, such as Congenital melanocytic naevus, frequently arise from somatic variants, meaning they are acquired during a person's lifetime rather than inherited from parents.
Which types of medical panels include the NRAS gene in the UK?
In the UK, the NRAS gene is covered on several NHS Genomic Medicine Service PanelApp panels, including those for adult and childhood solid tumours, foetal anomalies, intellectual disability, and RASopathies.
Can lifestyle changes prevent NRAS-related conditions?
While no specific lifestyle interventions are known to prevent NRAS-related conditions, maintaining a generally healthy lifestyle through balanced diet and regular physical activity supports overall well-being and cellular health.
References
- Charbel C, Fontaine RH, Malouf GG. NRAS mutation is the sole recurrent somatic mutation in large congenital melanocytic nevi. The Journal of investigative dermatology. 2014. PMID: 24129063
- Cirstea IC, Kutsche K, Dvorsky R. A restricted spectrum of NRAS mutations causes Noonan syndrome. Nature genetics. 2010. PMID: 19966803
- Romano AA, Allanson JE, Dahlgren J. Noonan syndrome: clinical features, diagnosis, and management guidelines. Pediatrics. 2010. PMID: 20876176
- Eskandarpour M, Huang F, Reeves KA. Oncogenic NRAS has multiple effects on the malignant phenotype of human melanoma cells cultured in vitro. International journal of cancer. 2009. PMID: 18814281