NM_000022.4:c.703C>T

Variant names:

Variant summary

Our verdict is Likely pathogenic. The variant received 7 ACMG points: 7P and 0B. PP4PM5_SupportingPM3_StrongPM2_Supporting

This summary comes from the ClinGen Evidence Repository: The c.703C>T (NM_000022.4) variant in ADA gene is a missense variant predicted to cause substitution of Arginine by Tryptophan at amino acid 235 (p.Arg235Trp).The filtering allele frequency based on the European (non-Finnish) population (upper bound of 95% CI of 2/113770 observed alleles) is 0.000002920 in gnomAD v2.1.1 which is below than SCID VCEP threshold (<0.0001742) and therefore meets this criterion (PM2_Supporting). This variant has been detected in at least 5 individuals with SCID. Of those individuals, 2 were compound heterozygous: Patient #6, W264X, reported by Dalal I et al. (PMID:21624848, Pathogenic according to the SCID VCEP specifications, confirmed in trans, 1pt) and Patient #26, p.G74D, reported by Chi ZH et al. (PMID:30290665, Likey Pathogenic according to the SCID VCEP, confirmed in trans, 1 pt). 3 individuals were homozygous for PMIDs: 26255240, 26376800, and 32307643; reaching the limit for homozygous occurrence = 1 pt). Total = 3 pts, PM3_Strong.Evaluating those 5 probands, three of them had PP4 applied at supporting level: * PMID:30290665: 171 PID-related genes(NGS panel: 0.5pt); T-B-SCID ( SCID gene panel which ruled out alternative causes 0.5pt); SCID diagnostic (0.5pt); Total 1.5pts. * PMID:26376800: Diagnostic criteria for SCID: 0,5 pt + Reduced ADA enzyme activity in patient cells: 1pt. TOTAL: 1.5 pts, PP4_Met. * PMID:26255240: Diagnostic criteria for SCID: 0,5 pt + Reduced ADA enzyme activity in patient cells: 1pt = TOTAL: 1.5 pts = PP4_Met. In summary, this variant meets the criteria to be classified as Likely Pathogenic for autosomal recessive SCID based on the ACMG/AMP criteria applied, as specified by the ClinGen SCID VCEP. Criteria applied: PM2_Supporting, PP4, PM3_Strong, and PM5_supporting. (VCEP specifications version 1). LINK:https://erepo.genome.network/evrepo/ui/classification/CA9871550/MONDO:0007064/114

Frequency

Genomes: 𝑓 0.000013 ( 0 hom., cov: 33)

Exomes 𝑓: 0.000011 ( 0 hom. )

Consequence

ADA
NM_000022.4 missense

Scores

Clinical Significance

Likely pathogenic reviewed by expert panel P:7

Conservation

PhyloP100: 2.39

Publications

5 publications found

Variant links:

Genes affected

ADA (HGNC:186): (adenosine deaminase) This gene encodes an enzyme that catalyzes the hydrolysis of adenosine to inosine in the purine catabolic pathway. Various mutations have been described for this gene and have been linked to human diseases related to impaired immune function such as severe combined immunodeficiency disease (SCID) which is the result of a deficiency in the ADA enzyme. In ADA-deficient individuals there is a marked depletion of T, B, and NK lymphocytes, and consequently, a lack of both humoral and cellular immunity. Conversely, elevated levels of this enzyme are associated with congenital hemolytic anemia. [provided by RefSeq, Sep 2019]

ADA links:

PKIG (HGNC:9019): (cAMP-dependent protein kinase inhibitor gamma) This gene encodes a member of the protein kinase inhibitor family. Studies of a similar protein in mice suggest that this protein acts as a potent competitive cAMP-dependent protein kinase inhibitor, and is a predominant form of inhibitor in various tissues. The encoded protein may be involved in osteogenesis. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Jul 2013]

PKIG links:

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ACMG classification

Classification was made for transcript

Our verdict: Likely_pathogenic. The variant received 7 ACMG points.

PM2

For more information check the summary or visit ClinGen Evidence Repository.

PM3

For more information check the summary or visit ClinGen Evidence Repository.

PM5

For more information check the summary or visit ClinGen Evidence Repository.

PP4

For more information check the summary or visit ClinGen Evidence Repository.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein
ADA	NM_000022.4 link	c.703C>T	p.Arg235Trp	missense_variant	Exon 8 of 12	ENST00000372874.9	NP_000013.2
ADA	NM_001322051.2 link	c.631C>T	p.Arg211Trp	missense_variant	Exon 7 of 11		NP_001308980.1
ADA	NM_001322050.2 link	c.298C>T	p.Arg100Trp	missense_variant	Exon 7 of 11		NP_001308979.1
ADA	NR_136160.2 link	n.795C>T		non_coding_transcript_exon_variant	Exon 8 of 11

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein
ADA	ENST00000372874.9 link	c.703C>T	p.Arg235Trp	missense_variant	Exon 8 of 12	1	NM_000022.4	ENSP00000361965.4
ADA	ENST00000695995.1 link	c.313C>T	p.Arg105Trp	missense_variant	Exon 5 of 9			ENSP00000512318.1
ADA	ENST00000695991.1 link	c.241C>T	p.Arg81Trp	missense_variant	Exon 4 of 8			ENSP00000512314.1
ADA	ENST00000696038.1 link	n.*525C>T		non_coding_transcript_exon_variant	Exon 7 of 9			ENSP00000512344.1
ADA	ENST00000696038.1 link	n.*525C>T		3_prime_UTR_variant	Exon 7 of 9			ENSP00000512344.1

Frequencies

GnomAD3 genomes

AF:

0.0000131

AC:

AN:

152206

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:

0.00

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.0000294

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.0000159

AC:

AN:

251496

AF XY:

0.0000147

show subpopulations

Gnomad AFR exome

AF:

0.0000615

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:

0.0000176

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000109

AC:

AN:

1461890

Hom.:

Cov.:

AF XY:

0.0000110

AC XY:

AN XY:

727248

show subpopulations

African (AFR)

AF:

0.0000299

AC:

AN:

33480

American (AMR)

AF:

0.00

AC:

AN:

44724

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26136

East Asian (EAS)

AF:

0.0000252

AC:

AN:

39700

South Asian (SAS)

AF:

0.0000232

AC:

AN:

86256

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53420

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

0.00000899

AC:

AN:

1112012

Other (OTH)

AF:

0.0000331

AC:

AN:

60394

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.469

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:

0.0000131

AC:

AN:

152206

Hom.:

Cov.:

AF XY:

0.0000134

AC XY:

AN XY:

74352

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

41436

American (AMR)

AF:

0.00

AC:

AN:

15286

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.00

AC:

AN:

5200

South Asian (SAS)

AF:

0.00

AC:

AN:

4836

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10616

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.0000294

AC:

AN:

68040

Other (OTH)

AF:

0.00

AC:

AN:

2092

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.475

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Alfa

AF:

0.0000305

Hom.:

Bravo

AF:

0.0000113

ExAC

AF:

0.0000165

AC:

EpiCase

AF:

0.00

EpiControl

AF:

0.0000593

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:7

Revision: reviewed by expert panel

LINK: link

Submissions by phenotype

Severe combined immunodeficiency, autosomal recessive, T cell-negative, B cell-negative, NK cell-negative, due to adenosine deaminase deficiency

Pathogenic:6

Aug 10, 2021

Genome-Nilou Lab

Significance:Likely pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Nov 14, 2023

ClinGen Severe Combined Immunodeficiency Variant Curation Expert Panel, ClinGen

Significance:Likely pathogenic

Review Status:reviewed by expert panel

Collection Method:curation

The c.703C>T (NM_000022.4) variant in ADA gene is a missense variant predicted to cause substitution of Arginine by Tryptophan at amino acid 235 (p.Arg235Trp). The filtering allele frequency based on the European (non-Finnish) population (upper bound of 95% CI of 2/113770 observed alleles) is 0.000002920 in gnomAD v2.1.1 which is below than SCID VCEP threshold (<0.0001742) and therefore meets this criterion (PM2_Supporting). This variant has been detected in at least 5 individuals with SCID. Of those individuals, 2 were compound heterozygous: Patient #6, W264X, reported by Dalal I et al. (PMID: 21624848, Pathogenic according to the SCID VCEP specifications, confirmed in trans, 1pt) and Patient #26, p.G74D, reported by Chi ZH et al. (PMID: 30290665, Likey Pathogenic according to the SCID VCEP, confirmed in trans, 1 pt). 3 individuals were homozygous for PMIDs: 26255240, 26376800, and 32307643; reaching the limit for homozygous occurrence = 1 pt). Total = 3 pts, PM3_Strong. Evaluating those 5 probands, three of them had PP4 applied at supporting level: * PMID: 30290665: 171 PID-related genes(NGS panel: 0.5pt); T-B-SCID ( SCID gene panel which ruled out alternative causes 0.5pt); SCID diagnostic (0.5pt); Total 1.5pts. * PMID: 26376800: Diagnostic criteria for SCID: 0,5 pt + Reduced ADA enzyme activity in patient cells: 1pt. TOTAL: 1.5 pts, PP4_Met. * PMID: 26255240: Diagnostic criteria for SCID: 0,5 pt + Reduced ADA enzyme activity in patient cells: 1pt = TOTAL: 1.5 pts = PP4_Met. In summary, this variant meets the criteria to be classified as Likely Pathogenic for autosomal recessive SCID based on the ACMG/AMP criteria applied, as specified by the ClinGen SCID VCEP. Criteria applied: PM2_Supporting, PP4, PM3_Strong, and PM5_supporting. (VCEP specifications version 1). -

Mar 30, 2021

Natera, Inc.

Significance:Pathogenic

Review Status:no assertion criteria provided

Collection Method:clinical testing

- -

Sep 27, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

For these reasons, this variant has been classified as Pathogenic. This variant disrupts the p.Arg234 amino acid residue in ADA. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 11313286). This suggests that this residue is clinically significant, and that variants that disrupt this residue are likely to be disease-causing. Experimental studies have shown that this missense change affects ADA function (PMID: 9361033). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is expected to disrupt ADA protein function. ClinVar contains an entry for this variant (Variation ID: 468281). This missense change has been observed in individual(s) with SCID (PMID: 21624848, 26255240). In at least one individual the data is consistent with being in trans (on the opposite chromosome) from a pathogenic variant. This variant is present in population databases (rs778809577, gnomAD 0.007%). This sequence change replaces arginine, which is basic and polar, with tryptophan, which is neutral and slightly polar, at codon 235 of the ADA protein (p.Arg235Trp). -

Apr 12, 2018

Counsyl

Significance:Likely pathogenic

Review Status:no assertion criteria provided

Collection Method:clinical testing

This submission and the accompanying classification are no longer maintained by the submitter. For more information on current observations and classification, please contact variantquestions@myriad.com. -

Aug 22, 2023

Baylor Genetics

Significance:Likely pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

ADA-related disorder

Pathogenic:1

Dec 29, 2022

PreventionGenetics, part of Exact Sciences

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The ADA c.703C>T variant is predicted to result in the amino acid substitution p.Arg235Trp. This variant was reported in the compound heterozygous and homozygous states in patients with severe combined immunodeficiency (Dalal et al 2011. PubMed ID: 21624848; Patient 26 in Chi et al 2018. PubMed ID: 30290665; Pajno et al 2020. PubMed ID: 32307643). This variant is reported in 0.0062% of alleles in individuals of African descent in gnomAD (http://gnomad.broadinstitute.org/variant/20-43251547-G-A). Of note, a different variant at the same amino acid (p.Arg235Gln) has also been reported in patients with ADA-related disorder (Ariga et al. 2001. PubMed ID: 11313286). Based on this evidence, we interpret that c.703C>T (p.Arg235Trp) variant as pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Pathogenic

0.86

BayesDel_addAF

Pathogenic

0.39

BayesDel_noAF

Pathogenic

0.50

CADD

Pathogenic

(source)

DANN

Pathogenic

1.0

DEOGEN2

Pathogenic

0.99

D;D

Eigen

Uncertain

0.67

Eigen_PC

Uncertain

0.55

FATHMM_MKL

Uncertain

0.81

LIST_S2

Uncertain

0.94

D;D

M_CAP

Pathogenic

0.41

MetaRNN

Pathogenic

0.99

D;D

MetaSVM

Pathogenic

1.1

PhyloP100

2.4

PrimateAI

Uncertain

0.59

PROVEAN

Pathogenic

-7.3

D;D

REVEL

Pathogenic

0.97

Sift

Pathogenic

0.0

D;D

Sift4G

Pathogenic

0.0

D;D

Polyphen

1.0

D;.

Vest4

0.98

MVP

0.98

MPC

0.64

ClinPred

0.99

GERP RS

4.2

Varity_R

0.97

gMVP

0.97

Mutation Taster

=1/99

disease causing (ClinVar)

(source)

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

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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