2-162281369-C-G

Variant names:

• chr2-162281369-C-G
• NM_022168.4:c.1483G>C

Variant summary

Our verdict is Uncertain significance. Variant got 2 ACMG points: 2P and 0B. PM2

The NM_022168.4(IFIH1):​c.1483G>C​(p.Gly495Arg) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: IFIH1 NM_022168.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 3.19

Genes affected

IFIH1 (HGNC:18873): (interferon induced with helicase C domain 1) IFIH1 encodes MDA5 which is an intracellular sensor of viral RNA that triggers the innate immune response. Sensing RNA length and secondary structure, MDA5 binds dsRNA oligonucleotides with a modified DExD/H-box helicase core and a C-terminal domain, thus leading to a proinflammatory response that includes interferons. It has been shown that Coronaviruses (CoVs) as well as various other virus families, are capable of evading the MDA5-dependent interferon response, thus impeding the activation of the innate immune response to infection. MDA5 has also been shown to play an important role in enhancing natural killer cell function in malaria infection. In addition to its protective role in antiviral responses, MDA5 has been implicated in autoimmune and autoinflammatory diseases such as type 1 diabetes, systemic lupus erythematosus, and Aicardi-Goutieres syndrome[provided by RefSeq, Jul 2020]

ACMG classification

Verdict is Uncertain_significance. Variant got 2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
IFIH1	NM_022168.4	c.1483G>C	p.Gly495Arg	missense_variant	Exon 7 of 16	ENST00000649979.2	NP_071451.2
IFIH1	XM_047445407.1	c.766G>C	p.Gly256Arg	missense_variant	Exon 6 of 15		XP_047301363.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
IFIH1	ENST00000649979.2	c.1483G>C	p.Gly495Arg	missense_variant	Exon 7 of 16		NM_022168.4	ENSP00000497271.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Aicardi-Goutieres syndrome 7;C4225427:Singleton-Merten syndrome 1 Uncertain:1

Oct 18, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Advanced modeling performed at Invitae incorporating data from internal and/or published experimental studies (Invitae) did not meet the statistical confidence thresholds required to predict the impact of this variant on IFIH1 function. This sequence change replaces glycine, which is neutral and non-polar, with arginine, which is basic and polar, at codon 495 of the IFIH1 protein (p.Gly495Arg). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individual(s) with clinical features of Aicardi-Goutieres syndrome (PMID: 24686847). Experimental studies have shown that this missense change affects IFIH1 function (PMID: 24686847). 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

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.13
BayesDel_addAF	Benign	-0.12	T
BayesDel_noAF	Benign	-0.41
CADD	Uncertain	24
DANN	Pathogenic	1.0
DEOGEN2	Uncertain	0.44	T;T;.
Eigen	Uncertain	0.60
Eigen_PC	Uncertain	0.55
FATHMM_MKL	Uncertain	0.96	D
LIST_S2	Uncertain	0.92	.;D;D
M_CAP	Uncertain	0.10	D
MetaRNN	Uncertain	0.65	D;D;D
MetaSVM	Benign	-1.1	T
MutationAssessor	Benign	2.0	M;M;.
PrimateAI	Uncertain	0.52	T
PROVEAN	Pathogenic	-5.4	.;D;.
REVEL	Pathogenic	0.72
Sift	Benign	0.037	.;D;.
Sift4G	Benign	0.070	.;T;.
Polyphen		0.98	D;D;.
Vest4		0.45
MutPred		0.54		Loss of ubiquitination at K498 (P = 0.0236);Loss of ubiquitination at K498 (P = 0.0236);Loss of ubiquitination at K498 (P = 0.0236);
MVP		0.68
MPC		0.049
ClinPred		0.94	D
GERP RS		4.0
Varity_R		0.38
gMVP		0.71

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.030		Details are displayed if max score is > 0.2

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

Publications

No publications associated with this variant yet.

Other links and lift over

hg19: chr2-163137879;