The c.71T>A (p.Ile24Asn) variant in NRAS is a missense variant predicted to cause substitution of isoleucine by asparagine at amino acid 24. This variant is absent from gnomAD v2.1.1 (PM2_Supporting). The computational predictor REVEL gives a score of 0.863, which is above the threshold of 0.7, evidence that correlates with impact to NRAS function (PP3). This variant has been reported in 4 probands with features of RASopathy (PS4_Moderate; PMIDs:21263000, 22855653, 28594414, GeneDx). This variant has been identified as a de novo occurrence with unconfirmed parental relationships in 2 individuals with features of RASopathy (PM6_Strong; PMIDs: 21263000, 22855653). RAS activation assays in 293T cells showed a mild increase in GTP-bound RAS and enhanced MAPK phosphorylation indicating that this variant impacts protein function. A zebrafish model using injected RNA showed developmental and craniofacial defects. The phenotype was completely rescued by MEK inhibition (PMID:21263000)(PS3_Supporting). In summary, this variant meets the criteria to be classified as likely pathogenic for autosomal dominant RASopathy based on the ACMG/AMP criteria applied, as specified by the ClinGen RASopathy VCEP: PM6_Strong, PS4_Moderate, PS3_Supporting, PM2_Supporting, PP3. (RASopathy VCEP specifications version 2.1; 9/17/2024)