Abstract:

Objective To explore the molecular characteristics of giant congenital melanocytic nevi (GCMN) and their

clinical significance. Methods The samples of patients diagnosed with GCMN were subjected whole-exome sequencing and

bio-information analysis to clarify the pathogenic genes and distribution patterns. Results In 50 samples (25 pairs of tissues

and blood) from 25 patients, 21 patients had somatic mutations, including NRAS gene (19 cases) and BRAF gene (1 case). New

mutations were detected in 2 patients’

lesions and blood, and the mutant genes were MET gene and IDH1 gene. In addition,

no causative mutation was detected in 4 patients. There was no statistic difference between GCMN genotype and phenotype.

Conclusion NRAS somatic mutation is the most common mutation in GCMN, and BRAF gene has also been detected. Potential

new mutated IDH1 and MET genes were also found.

Key words:

Giant nevus, 　Congenital melanocytic nevus, 　Whole-exome sequencing, 　Gene mutation