2-162268127-T-G

Variant names:

• chr2-162268127-T-G
• rs35667974
• NM_022168.4:c.2767A>C

Variant summary

Our verdict is Uncertain significance. The variant received 2 ACMG points: 2P and 0B. PM2

The NM_022168.4(IFIH1):​c.2767A>C​(p.Ile923Leu) variant causes a missense change. The variant was absent in control chromosomes in GnomAD project. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. I923V) has been classified as Likely benign.

• Frequency: Genomes: not found (cov: 32)
• Consequence: IFIH1 NM_022168.4 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 5.71
• Publications: 106 publications found

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

ACMG classification

Our verdict: Uncertain_significance. The variant received 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.2767A>C	p.Ile923Leu	missense_variant	Exon 14 of 16	ENST00000649979.2	NP_071451.2
IFIH1	XM_047445407.1	c.2050A>C	p.Ile684Leu	missense_variant	Exon 13 of 15		XP_047301363.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
IFIH1	ENST00000649979.2	c.2767A>C	p.Ile923Leu	missense_variant	Exon 14 of 16		NM_022168.4	ENSP00000497271.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 30

GnomAD4 genome Cov.: 32

Alfa AF: 0.00 Hom.: 67

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.21
BayesDel_addAF	Benign	0.011	T
BayesDel_noAF	Benign	-0.22
CADD	Uncertain	24
DANN	Uncertain	0.99
DEOGEN2	Benign	0.16	T;T;.
Eigen	Uncertain	0.51
Eigen_PC	Uncertain	0.52
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.92	.;D;D
M_CAP	Benign	0.031	D
MetaRNN	Uncertain	0.49	T;T;T
MetaSVM	Benign	-0.58	T
MutationAssessor	Uncertain	2.4	M;M;.
PhyloP100		5.7
PrimateAI	Uncertain	0.53	T
PROVEAN	Benign	-1.7	.;N;.
REVEL	Benign	0.23
Sift	Uncertain	0.0080	.;D;.
Sift4G	Uncertain	0.056	.;T;.
Polyphen		0.58	P;P;.
Vest4		0.57
MutPred		0.42		Gain of catalytic residue at I923 (P = 0.0559);Gain of catalytic residue at I923 (P = 0.0559);.;
MVP		0.64
MPC		0.20
ClinPred		0.93	D
GERP RS		5.1
Varity_R		0.83
gMVP		0.65
Mutation Taster		=61/39	polymorphism

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

Other links and lift over

dbSNP: rs35667974; hg19: chr2-163124637;