NM_022168.4:c.1996C>G

Variant names:

Variant summary

Our verdict is Likely benign. The variant received -2 ACMG points: 2P and 4B. PM2BP4_Strong

The NM_022168.4(IFIH1):c.1996C>G(p.Pro666Ala) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000137 in 1,456,498 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 16/22 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. P666S) has been classified as Likely benign.

Frequency

Genomes: not found (cov: 32)

Exomes 𝑓: 0.0000014 ( 0 hom. )

Consequence

IFIH1
NM_022168.4 missense

Scores

Clinical Significance

Uncertain significance criteria provided, single submitter U:1

Conservation

PhyloP100: 0.254

Publications

2 publications found

Variant links:

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]

IFIH1 Gene-Disease associations (from GenCC):

Aicardi-Goutieres syndrome 7
Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: PanelApp Australia, Illumina, Labcorp Genetics (formerly Invitae), G2P
Singleton-Merten syndrome 1
Inheritance: AD Classification: STRONG Submitted by: G2P, Labcorp Genetics (formerly Invitae)
Aicardi-Goutieres syndrome
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
Singleton-Merten dysplasia
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
immunodeficiency 95
Inheritance: AR Classification: LIMITED Submitted by: Ambry Genetics

IFIH1 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Likely_benign. The variant received -2 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

BP4

Computational evidence support a benign effect (MetaRNN=0.037502915).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
IFIH1	NM_022168.4 link	c.1996C>G	p.Pro666Ala	missense_variant	Exon 10 of 16	ENST00000649979.2	NP_071451.2	Q9BYX4-1
IFIH1	XM_047445407.1 link	c.1279C>G	p.Pro427Ala	missense_variant	Exon 9 of 15		XP_047301363.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
IFIH1	ENST00000649979.2 link	c.1996C>G	p.Pro666Ala	missense_variant	Exon 10 of 16		NM_022168.4	ENSP00000497271.1		Q9BYX4-1

Frequencies

GnomAD3 genomes

Cov.:

GnomAD2 exomes

AF:

0.00000409

AC:

AN:

244328

AF XY:

0.00

show subpopulations

Gnomad AFR exome

AF:

0.0000629

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000137

AC:

AN:

1456498

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

724458

show subpopulations

⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.

African (AFR)

AF:

0.00

AC:

AN:

33396

American (AMR)

AF:

0.00

AC:

AN:

44348

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26008

East Asian (EAS)

AF:

0.00

AC:

AN:

39576

South Asian (SAS)

AF:

0.00

AC:

AN:

85926

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53152

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5762

European-Non Finnish (NFE)

AF:

0.00000180

AC:

AN:

1108162

Other (OTH)

AF:

0.00

AC:

AN:

60168

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0.000000), which strongly suggests a high chance of mosaicism in these individuals.

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.275

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

GnomAD4 genome

Cov.:

Alfa

AF:

0.00

Hom.:

Bravo

AF:

0.0000113

ESP6500AA

AF:

0.00

AC:

ESP6500EA

AF:

0.000116

AC:

ExAC

AF:

0.00000825

AC:

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

LINK: link

Submissions by phenotype

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

Uncertain:1

Apr 03, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change replaces proline, which is neutral and non-polar, with alanine, which is neutral and non-polar, at codon 666 of the IFIH1 protein (p.Pro666Ala). This variant is present in population databases (rs376074455, gnomAD 0.007%). This variant has not been reported in the literature in individuals affected with IFIH1-related conditions. ClinVar contains an entry for this variant (Variation ID: 1909534). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) has been performed at Invitae for this missense variant, however the output from this modeling did not meet the statistical confidence thresholds required to predict the impact of this variant on IFIH1 protein function. 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

0.077

BayesDel_addAF

Benign

-0.45

BayesDel_noAF

Benign

-0.70

CADD

Benign

0.35

(source)

DANN

Benign

0.48

DEOGEN2

Benign

0.048

T;T;.

Eigen

Benign

-1.3

Eigen_PC

Benign

-1.2

FATHMM_MKL

Benign

0.20

LIST_S2

Benign

0.58

.;T;T

M_CAP

Benign

0.0055

MetaRNN

Benign

0.038

T;T;T

MetaSVM

Benign

-0.91

MutationAssessor

Benign

1.8

L;L;.

PhyloP100

0.25

PrimateAI

Benign

0.23

PROVEAN

Benign

-0.40

.;N;.

REVEL

Benign

0.0090

Sift

Benign

0.26

.;T;.

Sift4G

Benign

0.31

.;T;.

Polyphen

0.0

B;B;.

Vest4

0.19

MVP

0.26

MPC

0.024

ClinPred

0.023

GERP RS

-0.098

Varity_R

0.023

gMVP

0.17

Mutation Taster

=97/3

polymorphism

(source)

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

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NM_022168.4:c.1996C>G

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over