chr2-162279995-C-T

Variant names:

• chr2-162279995-C-T
• rs35337543
• NM_022168.4:c.1641+1G>A

Variant summary

Our verdict is Uncertain significance. The variant received 4 ACMG points: 4P and 0B. PVS1_Moderate PM2

The NM_022168.4(IFIH1):​c.1641+1G>A variant causes a splice donor, intron change. The variant allele was found at a frequency of 0.00000368 in 1,359,678 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000037 (0 hom.)
• Consequence: IFIH1 NM_022168.4 splice_donor, intron
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 5.79
• Publications: 55 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: Labcorp Genetics (formerly Invitae), G2P, Illumina
• IFIH1-related type 1 interferonopathy

  Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
• Singleton-Merten syndrome 1

  Inheritance: AD Classification: STRONG Submitted by: Labcorp Genetics (formerly Invitae), G2P
• 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 4 ACMG points.

• PVS1: Splicing +-2 bp (donor or acceptor) variant, product NOT destroyed by NMD, known LOF gene, truncates exone, which is 0.038011696 fraction of the gene. No cryptic splice site detected. Exon removal is inframe change.
• PM2: Very rare variant in population databases, with high coverage

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

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	IFIH1	NM_022168.4	MANE Select	c.1641+1G>A		splice_donor intron	N/A	NP_071451.2

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	IFIH1	ENST00000649979.2	MANE Select	c.1641+1G>A		splice_donor intron	N/A	ENSP00000497271.1	Q9BYX4-1
	IFIH1	ENST00000648433.1		c.1524+1333G>A		intron	N/A	ENSP00000496816.1	A0A3B3IRK8
	IFIH1	ENST00000679938.1		c.1329+1G>A		splice_donor intron	N/A	ENSP00000505518.1	A0A7P0Z4A9

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD2 exomes AF: 0.00000800 AC: 2 AN: 249994 AF XY: 0.0000148

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: 0.0000177

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000368 AC: 5 AN: 1359678 Hom.: 0 Cov.: 23 AF XY: 0.00000293 AC XY: 2 AN XY: 682216

African (AFR) AF: 0.00 AC: 0 AN: 31220

American (AMR) AF: 0.00 AC: 0 AN: 44394

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 25490

East Asian (EAS) AF: 0.00 AC: 0 AN: 39182

South Asian (SAS) AF: 0.00 AC: 0 AN: 84088

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53296

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5536

European-Non Finnish (NFE) AF: 0.00000294 AC: 3 AN: 1019694

Other (OTH) AF: 0.0000352 AC: 2 AN: 56778

GnomAD4 genome Cov.: 33

Alfa AF: 0.00000864 Hom.: 8

ExAC AF: 0.00000824 AC: 1

EpiCase AF: 0.00

EpiControl AF: 0.0000593

ClinVar

ClinVar submissions

Significance: Uncertain significance

Revision: criteria provided, single submitter

Pathogenic	VUS	Benign	Condition
-	1	-	Aicardi-Goutieres syndrome 7;C4225427:Singleton-Merten syndrome 1 (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.41	D
BayesDel_noAF	Pathogenic	0.37
CADD	Pathogenic	28
DANN	Uncertain	0.99
Eigen	Pathogenic	1.1
Eigen_PC	Pathogenic	0.99
FATHMM_MKL	Pathogenic	0.98	D
PhyloP100		5.8
GERP RS		5.5
Mutation Taster		=0/100	disease causing

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.93
SpliceAI score (max)		0.86		Details are displayed if max score is > 0.2
DS_DL_spliceai		0.86		Position offset: 1

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Other links and lift over

dbSNP: rs35337543; hg19: chr2-163136505;