Large congenital melanocytic nevus: genes and variants
Large congenital melanocytic nevus is linked to 2 analyzed proteins (HRAS and NRAS). 5 DNA variants are known to cause it; 6 more are uncertain, and 0 of those already look disease-causing on computable evidence.
Last updated 2026-09-30. Research information, not medical advice.
Genes linked to Large congenital melanocytic nevus
HRAS: GTPase HRas
Its GTP-bound state activates RAF-MEK-ERK and other pathways downstream of growth-factor receptors. Somatic activating variants drive several cancers, while germline activating variants cause Costello syndrome.
5 disease-causing and 5 uncertain variants in HRAS are linked to Large congenital melanocytic nevus.
NRAS: GTPase NRas
Its active GTP-bound state drives RAF-MEK-ERK and PI3K signaling downstream of growth-factor receptors. Somatic activating variants are common drivers of melanoma, leukemia, and other cancers, while germline activating variants can cause Noonan syndrome.
0 disease-causing and 1 uncertain variants in NRAS are linked to Large congenital melanocytic nevus.
Known disease-causing variants in Large congenital melanocytic nevus
| Variant | Position | Protein part | Clinical label |
|---|---|---|---|
| HRAS G12C | 12 | Disease-causing (★★) | |
| HRAS G12A | 12 | Disease-causing (★★) | |
| HRAS G13V | 13 | Disease-causing (★★) | |
| HRAS G60V | 60 | Disease-causing (★★) | |
| HRAS Q61R | 61 | Disease-causing (★★) |
Same protein, different disease
- Costello syndrome is also caused by HRAS variants; they fall partly in the same places as the Large congenital melanocytic nevus variants (15 disease-causing).
- RASopathy is also caused by HRAS variants; they fall in the same places as the Large congenital melanocytic nevus variants (6 disease-causing).
Diseases related to Large congenital melanocytic nevus
- Hypertrophic cardiomyopathy, also linked to HRAS and NRAS
- RASopathy, also linked to HRAS and NRAS
- Noonan syndrome, also linked to HRAS and NRAS
- Noonan syndrome and Noonan-related syndrome, also linked to HRAS and NRAS
- Costello syndrome, also linked to HRAS and NRAS
- Linear nevus sebaceous syndrome, also linked to HRAS and NRAS
- Epidermal nevus, also linked to HRAS and NRAS
- Cardiofaciocutaneous syndrome, also linked to NRAS
- Acute myeloid leukemia, also linked to NRAS
- Autoimmune lymphoproliferative syndrome, also linked to NRAS
- Colorectal cancer, also linked to NRAS
- Malignant tumor of urinary bladder, also linked to HRAS
Frequently asked questions
Which genes are linked to Large congenital melanocytic nevus?
In CATVariant, Large congenital melanocytic nevus is linked to 2 analyzed proteins: HRAS (GTPase HRas) and NRAS (GTPase NRas).
How many genetic variants are linked to Large congenital melanocytic nevus?
19 variants: 5 are classified as disease-causing (pathogenic or likely pathogenic) in ClinVar and 6 are of uncertain significance or have conflicting reports.
Which uncertain variants in Large congenital melanocytic nevus look disease-causing?
None of the uncertain variants currently reaches the likely-pathogenic range on computable evidence alone.
About this data
Variant–disease links come from ClinVar, Open Targets and UniProt, pooled from the latest public CATVariant analysis of each human protein. Evidence scores use the ACMG/AMP Bayesian points scale with computable criteria only (position among known disease variants, rarity in gnomAD, calibrated predictors, deep mutational scanning); there is no family or patient data, so they prioritise variants for expert review and never classify them.
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