chr2-162280054-A-G

Position:

• chr2-162280054-A-G

Variant summary

Our verdict is Uncertain significance. Variant got 3 ACMG points: 3P and 0B. PM2 PP3

The NM_022168.4(IFIH1):​c.1583T>C​(p.Leu528Pro) variant causes a missense change. The variant allele was found at a frequency of 0.000000685 in 1,459,288 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic 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. L528R) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.9e-7 (0 hom.)
• Consequence: IFIH1 NM_022168.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 7.16

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 (HGNC:):

ACMG classification

Verdict is Uncertain_significance. Variant got 3 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.83

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
IFIH1	NM_022168.4	c.1583T>C	p.Leu528Pro	missense_variant	8/16	ENST00000649979.2	NP_071451.2
IFIH1	XM_047445407.1	c.866T>C	p.Leu289Pro	missense_variant	7/15		XP_047301363.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
IFIH1	ENST00000649979.2	c.1583T>C	p.Leu528Pro	missense_variant	8/16		NM_022168.4	ENSP00000497271.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD3 exomes AF: 0.0000120 AC: 3 AN: 250364 Hom.: 0 AF XY: 0.0000148 AC XY: 2 AN XY: 135362

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.000163

Gnomad SAS 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: 6.85e-7 AC: 1 AN: 1459288 Hom.: 0 Cov.: 29 AF XY: 0.00000138 AC XY: 1 AN XY: 726066

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.0000252

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

Bravo AF: 0.00000378

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

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Feb 24, 2022

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: "Deleterious"; PolyPhen-2: "Benign"; Align-GVGD: "Class C25"). This variant has not been reported in the literature in individuals affected with IFIH1-related conditions. This variant is present in population databases (rs142348767, gnomAD 0.01%). This sequence change replaces leucine, which is neutral and non-polar, with proline, which is neutral and non-polar, at codon 528 of the IFIH1 protein (p.Leu528Pro). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.78
BayesDel_addAF	Uncertain	0.10	D
BayesDel_noAF	Uncertain	0.13
CADD	Uncertain	25
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.64	D;D
Eigen	Pathogenic	0.82
Eigen_PC	Pathogenic	0.76
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Benign	0.69	.;T
M_CAP	Benign	0.063	D
MetaRNN	Pathogenic	0.83	D;D
MetaSVM	Benign	-1.1	T
MutationAssessor	Pathogenic	3.6	H;H
PrimateAI	Uncertain	0.65	T
PROVEAN	Pathogenic	-5.4	.;D
REVEL	Uncertain	0.51
Sift	Uncertain	0.0020	.;D
Sift4G	Uncertain	0.0050	.;D
Polyphen		1.0	D;D
Vest4		0.94
MutPred		0.61		Gain of sheet (P = 0.0073);Gain of sheet (P = 0.0073);
MVP		0.70
MPC		0.076
ClinPred		0.99	D
GERP RS		5.4
Varity_R		0.96
gMVP		0.91

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: rs142348767; hg19: chr2-163136564;