2-162278205-CTTT-CTT

Variant names:

Variant summary

Our verdict is Likely pathogenic. The variant received 9 ACMG points: 9P and 0B. PVS1PP5

The NM_022168.4(IFIH1):c.1764delA(p.Ala589LeufsTer16) variant causes a frameshift, splice region change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000175 in 1,599,554 control chromosomes in the GnomAD database, with no homozygous occurrence. 1/1 splice prediction tools predict no significant impact on normal splicing. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Variant results in nonsense mediated mRNA decay.

Frequency

Genomes: 𝑓 0.0000066 ( 0 hom., cov: 32)

Exomes 𝑓: 0.000019 ( 0 hom. )

Consequence

IFIH1
NM_022168.4 frameshift, splice_region

Scores

Not classified

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:1U:2

Conservation

PhyloP100: 2.56

Publications

4 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_pathogenic. The variant received 9 ACMG points.

PVS1

Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.

PP5

Variant 2-162278205-CT-C is Pathogenic according to our data. Variant chr2-162278205-CT-C is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 987915.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
IFIH1	NM_022168.4 link	c.1764delA	p.Ala589LeufsTer16	frameshift_variant, splice_region_variant	Exon 9 of 16	ENST00000649979.2	NP_071451.2	Q9BYX4-1
IFIH1	XM_047445407.1 link	c.1047delA	p.Ala350LeufsTer16	frameshift_variant, splice_region_variant	Exon 8 of 15		XP_047301363.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
IFIH1	ENST00000649979.2 link	c.1764delA	p.Ala589LeufsTer16	frameshift_variant, splice_region_variant	Exon 9 of 16		NM_022168.4	ENSP00000497271.1		Q9BYX4-1

Frequencies

GnomAD3 genomes

AF:

0.00000658

AC:

AN:

151908

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.000193

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.00

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.0000853

AC:

AN:

234356

AF XY:

0.0000708

show subpopulations

Gnomad AFR exome

AF:

0.000130

Gnomad AMR exome

AF:

0.0000672

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.000236

Gnomad FIN exome

AF:

0.0000942

Gnomad NFE exome

AF:

0.0000646

Gnomad OTH exome

AF:

0.000176

GnomAD4 exome

AF:

0.0000187

AC:

AN:

1447528

Hom.:

Cov.:

AF XY:

0.0000153

AC XY:

AN XY:

719950

show subpopulations

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

African (AFR)

AF:

0.0000614

AC:

AN:

32550

American (AMR)

AF:

0.0000481

AC:

AN:

41614

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

25778

East Asian (EAS)

AF:

0.00

AC:

AN:

39310

South Asian (SAS)

AF:

0.0000240

AC:

AN:

83318

European-Finnish (FIN)

AF:

0.0000376

AC:

AN:

53206

Middle Eastern (MID)

AF:

0.00

AC:

AN:

4994

European-Non Finnish (NFE)

AF:

0.0000163

AC:

AN:

1107006

Other (OTH)

AF:

0.0000167

AC:

AN:

59752

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0), which strongly suggests a high chance of mosaicism in these individuals.

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.286

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

GnomAD4 genome

AF:

0.00000658

AC:

AN:

152026

Hom.:

Cov.:

AF XY:

0.0000135

AC XY:

AN XY:

74322

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

41454

American (AMR)

AF:

0.00

AC:

AN:

15246

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3470

East Asian (EAS)

AF:

0.000194

AC:

AN:

5164

South Asian (SAS)

AF:

0.00

AC:

AN:

4816

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10586

Middle Eastern (MID)

AF:

0.00

AC:

AN:

294

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

67974

Other (OTH)

AF:

0.00

AC:

AN:

2110

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.425

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Alfa

AF:

0.000130

Hom.:

Bravo

AF:

0.00000378

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:1Uncertain:2

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

Immunodeficiency 95

Pathogenic:1

Oct 04, 2024

Al Jalila Children’s Genomics Center, Al Jalila Childrens Speciality Hospital

Significance:Likely pathogenic

Review Status:criteria provided, single submitter

Collection Method:research

PVS1,PM2 -

Aicardi-Goutieres syndrome 7

Uncertain:1

Oct 04, 2020

Al Jalila Children’s Genomics Center, Al Jalila Childrens Speciality Hospital

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

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

Uncertain:1

Nov 05, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change creates a premature translational stop signal (p.Ala589Leufs*16) in the IFIH1 gene. It is expected to result in an absent or disrupted protein product. However, the current clinical and genetic evidence is not sufficient to establish whether loss-of-function variants in IFIH1 cause disease. The frequency data for this variant in the population databases is considered unreliable, as metrics indicate poor data quality at this position in the gnomAD database. This premature translational stop signal has been observed in individual(s) with IFIH1-related conditions (PMID: 36703223). ClinVar contains an entry for this variant (Variation ID: 987915). 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

PhyloP100

2.6

Mutation Taster

=44/156

disease causing (fs/PTC)

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.010

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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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