rs1553461143

Positions:

• chr2-162310807-C-G

Variant summary

Our verdict is Uncertain significance. Variant got 0 ACMG points: 2P and 2B. PM2 BP4_Moderate

The NM_022168.4(IFIH1):​c.580G>C​(p.Val194Leu) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,510 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 15/21 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: IFIH1 NM_022168.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 1.62

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 0 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.11016026).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
IFIH1	NM_022168.4	c.580G>C	p.Val194Leu	missense_variant	2/16	ENST00000649979.2	NP_071451.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
IFIH1	ENST00000649979.2	c.580G>C	p.Val194Leu	missense_variant	2/16		NM_022168.4	ENSP00000497271	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461510 Hom.: 0 Cov.: 30 AF XY: 0.00 AC XY: 0 AN XY: 727052

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

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: 8.99e-7

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

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

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Sep 09, 2017

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. Algorithms developed to predict the effect of missense changes on protein structure and function (SIFT, PolyPhen-2, Align-GVGD) all suggest that this variant is likely to be tolerated, but these predictions have not been confirmed by published functional studies and their clinical significance is uncertain. This variant has not been reported in the literature in individuals with IFIH1-related disease. This variant is not present in population databases (ExAC no frequency). This sequence change replaces valine with leucine at codon 194 of the IFIH1 protein (p.Val194Leu). The valine residue is weakly conserved and there is a small physicochemical difference between valine and leucine. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.16
BayesDel_addAF	Benign	-0.24	T
BayesDel_noAF	Benign	-0.59
CADD	Benign	9.1
DANN	Benign	0.59
DEOGEN2	Benign	0.019	T;T;.;.
Eigen	Benign	-0.52
Eigen_PC	Benign	-0.44
FATHMM_MKL	Uncertain	0.86	D
LIST_S2	Benign	0.80	.;T;T;T
M_CAP	Benign	0.0063	T
MetaRNN	Benign	0.11	T;T;T;T
MetaSVM	Benign	-1.0	T
MutationAssessor	Benign	1.9	L;L;.;L
MutationTaster	Benign	0.99	N;N;N
PrimateAI	Benign	0.31	T
PROVEAN	Benign	-0.13	.;N;.;N
REVEL	Benign	0.088
Sift	Benign	0.72	.;T;.;T
Sift4G	Benign	0.70	.;T;.;T
Polyphen		0.059	B;B;.;B
Vest4		0.22, 0.20
MutPred		0.59		Gain of catalytic residue at V194 (P = 0.0179);Gain of catalytic residue at V194 (P = 0.0179);Gain of catalytic residue at V194 (P = 0.0179);Gain of catalytic residue at V194 (P = 0.0179);
MVP		0.28
MPC		0.028
ClinPred		0.13	T
GERP RS		4.9
Varity_R		0.053
gMVP		0.46

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: rs1553461143; hg19: chr2-163167317;