Abstract: AbstractObjective: To summarize and review the clinical data of a case with systemic lupus erythematosus(SLE) caused by germline mutation in NRAS gene so as to improve the knowledge in spectrum of phenotype. Methods: Clinical data of a case with SLE were summarized, including clinical manifestations, laboratory findings and family investigation. The next generation sequencing was used to screen all exons of genomics in proband and her parents. Significant variants detected by next generation sequencing were confirmed by conventional Sanger sequencing and segregation analysis was performed using parental DNA and her brother samples.Results: The proband, 2.6-year-old boy, presented with recurrent fever and thrombocytopenia after age of 1 year. She often had rash, left knee joint swelling and pain, and mild proteinuria since the age of 2.6 years. At the same time, laboratory tests showed that ANA, anti-dsDNA antibody and other autoantibodies were positive. The patient had no abnormal facial features and no abnormalities in other organs. Whole exon sequencing was performed in core family, including proband and her parents. Heterozygous c.38G>A (p.G13D) mutation in NRAS gene was detected in proband, which was not carried by his parents. It was a de novo mutation.The mutation was confirmed by Sanger sequencing in core family. Conclusion: This study showed that a patient with germline mutation in NRAS gene could cause presenting with only SLE phenotype, and further extended the spectrum phenotype of mutations in NRAS gene.