1-155900398-GA-G

Variant names:

• chr1-155900398-GA-G
• rs1673287696
• NM_006912.6:c.649delT

Variant summary

Our verdict is Uncertain significance. Variant got 4 ACMG points: 4P and 0B. PVS1_Moderate PM2

The NM_006912.6(RIT1):​c.649delT​(p.Ser217GlnfsTer2) variant causes a frameshift change. The variant allele was found at a frequency of 0.000000685 in 1,460,770 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★). Synonymous variant affecting the same amino acid position (i.e. S217S) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: RIT1 NM_006912.6 frameshift
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 5.33

Genes affected

RIT1 (HGNC:10023): (Ras like without CAAX 1) This gene encodes a member of a subfamily of Ras-related GTPases. The encoded protein is involved in regulating p38 MAPK-dependent signaling cascades related to cellular stress. This protein also cooperates with nerve growth factor to promote neuronal development and regeneration. Alternate splicing results in multiple transcript variants. [provided by RefSeq, Feb 2012]

ACMG classification

Verdict is Uncertain_significance. Variant got 4 ACMG points.

• PVS1: Loss of function variant, product does not undergo nonsense mediated mRNA decay. Variant is located in the 3'-most exon, not predicted to undergo nonsense mediated mRNA decay. Fraction of 0.0167 CDS is truncated, and there are 0 pathogenic variants in the truncated region.
• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
RIT1	NM_006912.6	c.649delT	p.Ser217GlnfsTer2	frameshift_variant	Exon 6 of 6	ENST00000368323.8	NP_008843.1
RIT1	NM_001256821.2	c.700delT	p.Ser234GlnfsTer2	frameshift_variant	Exon 6 of 6		NP_001243750.1
RIT1	NM_001256820.2	c.541delT	p.Ser181GlnfsTer2	frameshift_variant	Exon 5 of 5		NP_001243749.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
RIT1	ENST00000368323.8	c.649delT	p.Ser217GlnfsTer2	frameshift_variant	Exon 6 of 6	1	NM_006912.6	ENSP00000357306.3

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.85e-7 AC: 1 AN: 1460770 Hom.: 0 Cov.: 30 AF XY: 0.00 AC XY: 0 AN XY: 726784

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.0000224

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Noonan syndrome 8 Uncertain:1

Jan 11, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change creates a premature translational stop signal (p.Ser217Glnfs*2) in the RIT1 gene. While this is not anticipated to result in nonsense mediated decay, it is expected to disrupt the last 3 amino acid(s) of the RIT1 protein. This variant is not present in population databases (gnomAD no frequency). This premature translational stop signal has been observed in individuals with clinical features of Noonan syndrome (Invitae). ClinVar contains an entry for this variant (Variation ID: 839801). In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. -

Computational scores

Source: dbNSFP v4.3

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.0		Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

LitVar

Other links and lift over

dbSNP: rs1673287696; hg19: chr1-155870189;