rs72650664

Variant names:

• chr2-162288184-T-A
• rs72650664
• NM_022168.4:c.1046A>T

Your query was ambiguous. Multiple possible variants found:

• chr2-162288184-T-A
• chr2-162288184-T-C

Variant summary

Our verdict is Uncertain significance. The variant received 1 ACMG points: 2P and 1B. PM2 BP4

The NM_022168.4(IFIH1):​c.1046A>T​(p.Lys349Met) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000685 in 1,460,642 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 14/22 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. K349R) has been classified as Likely benign.

• 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: 2.33
• Publications: 12 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 1 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.33010194).

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_022168.4. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	IFIH1	NM_022168.4	MANE Select	c.1046A>T	p.Lys349Met	missense	Exon 5 of 16	NP_071451.2

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	IFIH1	ENST00000649979.2	MANE Select	c.1046A>T	p.Lys349Met	missense	Exon 5 of 16	ENSP00000497271.1
	IFIH1	ENST00000648433.1		c.1046A>T	p.Lys349Met	missense	Exon 5 of 15	ENSP00000496816.1
	IFIH1	ENST00000679938.1		c.734A>T	p.Lys245Met	missense	Exon 4 of 15	ENSP00000505518.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD2 exomes AF: 0.00000399 AC: 1 AN: 250826 AF XY: 0.00000738

Gnomad AFR exome AF: 0.00

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: 0.00000882

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 6.85e-7 AC: 1 AN: 1460642 Hom.: 0 Cov.: 31 AF XY: 0.00 AC XY: 0 AN XY: 726660

African (AFR) AF: 0.00 AC: 0 AN: 33390

American (AMR) AF: 0.00 AC: 0 AN: 44600

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26076

East Asian (EAS) AF: 0.00 AC: 0 AN: 39684

South Asian (SAS) AF: 0.00 AC: 0 AN: 86232

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53392

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5690

European-Non Finnish (NFE) AF: 9.00e-7 AC: 1 AN: 1111282

Other (OTH) AF: 0.00 AC: 0 AN: 60296

GnomAD4 genome Cov.: 32

ExAC AF: 0.00000824 AC: 1

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

Sep 15, 2020

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant has not been reported in the literature in individuals with IFIH1-related conditions. This variant is present in population databases (rs72650664, ExAC 0.002%). This sequence change replaces lysine with methionine at codon 349 of the IFIH1 protein (p.Lys349Met). The lysine residue is moderately conserved and there is a moderate physicochemical difference between lysine and methionine. 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 are either unavailable or do not agree on the potential impact of this missense change (SIFT: "Tolerated"; PolyPhen-2: "Possibly Damaging"; Align-GVGD: "Class C0").

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.16
BayesDel_addAF	Benign	-0.021	T
BayesDel_noAF	Benign	-0.27
CADD	Benign	23
DANN	Uncertain	1.0
DEOGEN2	Benign	0.15	T
Eigen	Uncertain	0.64
Eigen_PC	Uncertain	0.64
FATHMM_MKL	Uncertain	0.92	D
LIST_S2	Benign	0.79	T
M_CAP	Benign	0.024	T
MetaRNN	Benign	0.33	T
MetaSVM	Benign	-0.44	T
MutationAssessor	Uncertain	2.2	M
PhyloP100		2.3
PrimateAI	Benign	0.35	T
PROVEAN	Benign	-2.2	N
REVEL	Benign	0.26
Sift	Benign	0.043	D
Sift4G	Benign	0.11	T
Polyphen		1.0	D
Vest4		0.47
MutPred		0.46		Loss of methylation at K349 (P = 0.0143)
MVP		0.84
MPC		0.18
ClinPred		0.80	D
GERP RS		6.0
Varity_R		0.37
gMVP		0.52
Mutation Taster		=51/49	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: rs72650664; hg19: chr2-163144694;