chr20-44625593-G-T

Variant summary

Our verdict is Uncertain significance. Variant got 3 ACMG points: 3P and 0B. PP1PP4_Moderate

This summary comes from the ClinGen Evidence Repository: The c.454C>A (NM_000022.4) variant in ADA is a missense variant predicted to cause substitution of Leu by Met at amino acid 152.The filtering allele frequency (the upper threshold of the 95% CI) of this variant is 0.0006937 for South Asian chromosomes by gnomAD v 2.1.1, which is bigger than the ClinGen SCID VCEP threshold (0.0001742). So, PM2 is not met.The variant has been reported to segregate with SCID in 02 affected members (proband +1) from one family. LOD score: 0.6 = PP1_supporting.At least one patient (P6, PMID:29744787) with this variant displayed: * Diagnostic criteria for SCID/Leaky SCID/Omenn syndrome met: 0.5 points, * Reduced ADA enzyme activity in patient cells (see table 2) 1 point, and * Lymphocyte count partially corrected by ADA enzyme replacement therapy: 1 point = TOTAL: 2.5 points, which is highly specific for SCID (PP4_moderate, PMID:29744787.)In summary, this variant meets the criteria to be classified as VUS for SCID. ACMG/AMP criteria applied, as specified by the ClinGen SCID-VCEP: PP1_Supporting, PP4_Moderate (SCID VCEP specifications version 1.0). LINK:https://erepo.genome.network/evrepo/ui/classification/CA115292/MONDO:0007064/114

Frequency

Genomes: 𝑓 0.000053 ( 0 hom., cov: 32)
Exomes 𝑓: 0.000092 ( 3 hom. )

Consequence

ADA
NM_000022.4 missense

Scores

11
6
2

Clinical Significance

Uncertain significance reviewed by expert panel P:12U:3O:1

Conservation

PhyloP100: 4.72
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]

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ACMG classification

Classification made for transcript

Verdict is Uncertain_significance. Variant got 3 ACMG points.

PP1
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 UniProt
ADANM_000022.4 linkc.454C>A p.Leu152Met missense_variant Exon 5 of 12 ENST00000372874.9 NP_000013.2 P00813A0A0S2Z381
ADANM_001322051.2 linkc.454C>A p.Leu152Met missense_variant Exon 5 of 11 NP_001308980.1 F5GWI4
ADANM_001322050.2 linkc.73+863C>A intron_variant Intron 4 of 10 NP_001308979.1
ADANR_136160.2 linkn.546C>A non_coding_transcript_exon_variant Exon 5 of 11

Ensembl

Gene Transcript HGVSc HGVSp Effect Exon rank TSL MANE Protein Appris UniProt
ADAENST00000372874.9 linkc.454C>A p.Leu152Met missense_variant Exon 5 of 12 1 NM_000022.4 ENSP00000361965.4 P00813
ADAENST00000695995.1 linkc.217-2515C>A intron_variant Intron 3 of 8 ENSP00000512318.1 A0A8Q3SI64
ADAENST00000695991.1 linkc.217-2663C>A intron_variant Intron 3 of 7 ENSP00000512314.1 A0A0S2Z3B9
ADAENST00000696038.1 linkn.*200C>A non_coding_transcript_exon_variant Exon 5 of 9 ENSP00000512344.1 A0A8Q3SJ57
ADAENST00000696038.1 linkn.*200C>A 3_prime_UTR_variant Exon 5 of 9 ENSP00000512344.1 A0A8Q3SJ57

Frequencies

GnomAD3 genomes
AF:
0.0000526
AC:
8
AN:
152210
Hom.:
0
Cov.:
32
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:
0.00103
Gnomad FIN
AF:
0.00
Gnomad MID
AF:
0.00
Gnomad NFE
AF:
0.0000441
Gnomad OTH
AF:
0.00
GnomAD3 exomes
AF:
0.000157
AC:
33
AN:
209700
Hom.:
0
AF XY:
0.000195
AC XY:
22
AN XY:
112748
show subpopulations
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 SAS exome
AF:
0.000990
Gnomad FIN exome
AF:
0.00
Gnomad NFE exome
AF:
0.0000547
Gnomad OTH exome
AF:
0.000377
GnomAD4 exome
AF:
0.0000920
AC:
132
AN:
1435350
Hom.:
3
Cov.:
31
AF XY:
0.000132
AC XY:
94
AN XY:
711490
show subpopulations
Gnomad4 AFR exome
AF:
0.00
Gnomad4 AMR exome
AF:
0.00
Gnomad4 ASJ exome
AF:
0.00
Gnomad4 EAS exome
AF:
0.0000259
Gnomad4 SAS exome
AF:
0.00137
Gnomad4 FIN exome
AF:
0.00
Gnomad4 NFE exome
AF:
0.00000819
Gnomad4 OTH exome
AF:
0.000101
GnomAD4 genome
AF:
0.0000525
AC:
8
AN:
152328
Hom.:
0
Cov.:
32
AF XY:
0.0000537
AC XY:
4
AN XY:
74490
show subpopulations
Gnomad4 AFR
AF:
0.00
Gnomad4 AMR
AF:
0.00
Gnomad4 ASJ
AF:
0.00
Gnomad4 EAS
AF:
0.00
Gnomad4 SAS
AF:
0.00103
Gnomad4 FIN
AF:
0.00
Gnomad4 NFE
AF:
0.0000441
Gnomad4 OTH
AF:
0.00
Alfa
AF:
0.0000445
Hom.:
0
Bravo
AF:
0.0000302
ExAC
AF:
0.000132
AC:
16
Asia WGS
AF:
0.000289
AC:
1
AN:
3478

ClinVar

Significance: Uncertain significance
Submissions summary: Pathogenic:12Uncertain:3Other:1
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:7Uncertain:3Other:1
Jun 22, 2023
Neuberg Centre For Genomic Medicine, NCGM
Significance: Likely pathogenic
Review Status: criteria provided, single submitter
Collection Method: clinical testing

The missense c.454C>A(p.Leu152Met) variant in ADA gene has been reported previously in homozygous and compound heterozygous states in multiple individuals affected with Severe Combined Immunodeficiency Syndrome / adenosine deaminase (ADA) deficiency (Cagdas D, et al., 2018; Firtina S, et al., 2020; 2020 CIS Annual Meeting: Immune Deficiency & Dysregulation North American Conference., 2020). This variant has also been observed to segregate with disease in related individuals. Functional expression studies of this variant showed that it leads to less enzymatic activity. However, it was concluded that p.Leu152Met variant will result in disease in homozygous individuals challenged by severe environmental stresses, or in heterozygous individuals when combined with another null variant (Hirschhorn R, et al., 1997). The p.Leu152Met variant is present with allele frequency of 0.02% in gnomAD Exomes. This variant has been reported to the ClinVar database as Uncertain Significance / Pathogenic / Likely Pathogenic (multiple submissions). Multiple lines of computational evidences (Polyphen - Probably damaging, SIFT - Damaging and MutationTaster - Disease causing) predict a damaging effect on protein structure and function for this variant. The reference amino acid at this position on ADA gene is predicted as conserved by GERP++ and PhyloP across 100 vertebrates. The amino acid Leu at position 152 is changed to a Met changing protein sequence and it might alter its composition and physico-chemical properties. Additional functional studies will be required to prove the pathogenicity of this variant conclusively. For these reasons, this variant has been classified as Likely Pathogenic. In absence of another reportable variant in ADA gene, the molecular diagnosis is not confirmed. -

Mar 14, 2018
Counsyl
Significance: Uncertain significance
Review Status: flagged submission
Collection Method: clinical testing

- -

Dec 29, 2020
Revvity Omics, Revvity
Significance: Likely pathogenic
Review Status: criteria provided, single submitter
Collection Method: clinical testing

- -

Jul 22, 2021
Genome-Nilou Lab
Significance: Likely pathogenic
Review Status: criteria provided, single submitter
Collection Method: clinical testing

- -

Nov 11, 2024
Labcorp Genetics (formerly Invitae), Labcorp
Significance: Pathogenic
Review Status: criteria provided, single submitter
Collection Method: clinical testing

This sequence change replaces leucine, which is neutral and non-polar, with methionine, which is neutral and non-polar, at codon 152 of the ADA protein (p.Leu152Met). This variant is present in population databases (rs121908728, gnomAD 0.1%). This missense change has been observed in individual(s) with delayed onset adenosine deaminase deficiency (PMID: 9225964, 29744787). It has also been observed to segregate with disease in related individuals. ClinVar contains an entry for this variant (Variation ID: 1979). Invitae Evidence Modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) indicates that this missense variant is expected to disrupt ADA protein function with a positive predictive value of 80%. Experimental studies have shown that this missense change affects ADA function (PMID: 9225964). For these reasons, this variant has been classified as Pathogenic. -

Mar 19, 2024
Baylor Genetics
Significance: Likely pathogenic
Review Status: criteria provided, single submitter
Collection Method: clinical testing

- -

Oct 10, 2023
ClinGen Severe Combined Immunodeficiency Variant Curation Expert Panel, ClinGen
Significance: Uncertain significance
Review Status: reviewed by expert panel
Collection Method: curation

The c.454C>A (NM_000022.4) variant in ADA is a missense variant predicted to cause substitution of Leu by Met at amino acid 152. The filtering allele frequency (the upper threshold of the 95% CI) of this variant is 0.0006937 for South Asian chromosomes by gnomAD v 2.1.1, which is bigger than the ClinGen SCID VCEP threshold (0.0001742). So, PM2 is not met. The variant has been reported to segregate with SCID in 02 affected members (proband +1) from one family. LOD score: 0.6 = PP1_supporting. At least one patient (P6, PMID: 29744787) with this variant displayed: * Diagnostic criteria for SCID/Leaky SCID/Omenn syndrome met: 0.5 points, * Reduced ADA enzyme activity in patient cells (see table 2) 1 point, and * Lymphocyte count partially corrected by ADA enzyme replacement therapy: 1 point = TOTAL: 2.5 points, which is highly specific for SCID (PP4_moderate, PMID: 29744787.) In summary, this variant meets the criteria to be classified as VUS for SCID. ACMG/AMP criteria applied, as specified by the ClinGen SCID-VCEP: PP1_Supporting, PP4_Moderate (SCID VCEP specifications version 1.0). -

May 18, 2021
Pars Genome Lab
Significance: Likely pathogenic
Review Status: criteria provided, single submitter
Collection Method: clinical testing

- -

-
UniProtKB/Swiss-Prot
Significance: not provided
Review Status: no classification provided
Collection Method: literature only

- -

Oct 31, 2018
Fulgent Genetics, Fulgent Genetics
Significance: Uncertain significance
Review Status: flagged submission
Collection Method: clinical testing

- -

Sep 01, 2022
3billion, Medical Genetics
Significance: Likely pathogenic
Review Status: criteria provided, single submitter
Collection Method: clinical testing

The variant is observed at an extremely low frequency in the gnomAD v2.1.1 dataset (total allele frequency: 0.014%). In silico tool predictions suggest damaging effect of the variant on gene or gene product (REVEL: 0.82; 3Cnet: 0.46). Same nucleotide change resulting in same amino acid change has been previously reported as pathogenic/likely pathogenic with strong evidence (ClinVar ID: VCV000001979). A different missense change at the same codon (p.Leu152Pro) has been reported to be associated with ADA-related disorder (PMID: 31031743). Therefore, this variant is classified as Likely pathogenic according to the recommendation of ACMG/AMP guideline. -

not provided Pathogenic:3
Jan 30, 2024
GeneDx
Significance: Likely pathogenic
Review Status: criteria provided, single submitter
Collection Method: clinical testing

Published in vitro functional studies demonstrate a damaging effect of L152M on ADA activity (PMID: 9225964); In silico analysis supports that this missense variant does not alter protein structure/function; This variant is associated with the following publications: (PMID: 14499267, 29744787, 34426522, 9225964, 36964972, 32445296) -

Jul 10, 2021
Kariminejad - Najmabadi Pathology & Genetics Center
Significance: Likely pathogenic
Review Status: criteria provided, single submitter
Collection Method: clinical testing

- -

Apr 01, 2021
CeGaT Center for Human Genetics Tuebingen
Significance: Likely pathogenic
Review Status: criteria provided, single submitter
Collection Method: clinical testing

- -

Partial adenosine deaminase deficiency Pathogenic:1
Jul 01, 1997
OMIM
Significance: Pathogenic
Review Status: no assertion criteria provided
Collection Method: literature only

- -

Severe combined immunodeficiency disease Pathogenic:1
Mar 24, 2022
Women's Health and Genetics/Laboratory Corporation of America, LabCorp
Significance: Likely pathogenic
Review Status: criteria provided, single submitter
Collection Method: clinical testing

Variant summary: ADA c.454C>A (p.Leu152Met) results in a conservative amino acid change located in the Adenosine/AMP deaminase domain (IPR001365) of the encoded protein sequence. Four of five in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 0.00016 in 209700 control chromosomes (gnomAD). This frequency is not significantly higher than expected for a pathogenic variant in ADA causing Severe Combined Immunodeficiency Syndrome (0.00016 vs 0.0016), allowing no conclusion about variant significance. c.454C>A has been reported in the literature in individuals affected with late-onset adenosine deaminase (ADA) deficiency (Cagdas_2018) and in a healthy homozygous individual with partial ADA deficiency (Hirschhorn 1997). These data indicate that the variant is likely to be associated with disease. Several publications report that ADA enzymatic activity could not be detected in the red cells with the variant (Hirschhorn_1997, Cagdas_2018). Eight clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014 without evidence for independent evaluation. Multiple laboratories reported the variant with conflicting assessments (pathogenic/likely pathogenic n=6, VUS n=2). Based on the evidence outlined above, the variant was classified as likely pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name
Calibrated prediction
Score
Prediction
AlphaMissense
Pathogenic
0.64
BayesDel_addAF
Pathogenic
0.20
D
BayesDel_noAF
Pathogenic
0.47
CADD
Uncertain
23
DANN
Uncertain
1.0
DEOGEN2
Pathogenic
0.83
D;D
Eigen
Uncertain
0.67
Eigen_PC
Uncertain
0.56
FATHMM_MKL
Uncertain
0.96
D
LIST_S2
Uncertain
0.96
D;D
M_CAP
Pathogenic
0.37
D
MetaRNN
Pathogenic
0.88
D;D
MetaSVM
Pathogenic
1.0
D
MutationAssessor
Pathogenic
4.1
H;.
PrimateAI
Uncertain
0.59
T
PROVEAN
Benign
-1.9
N;N
REVEL
Pathogenic
0.82
Sift
Pathogenic
0.0
D;D
Sift4G
Pathogenic
0.0
D;D
Polyphen
1.0
D;.
Vest4
0.79
MutPred
0.90
Gain of MoRF binding (P = 0.0678);Gain of MoRF binding (P = 0.0678);
MVP
0.86
MPC
0.62
ClinPred
0.54
D
GERP RS
3.5
Varity_R
0.93
gMVP
0.70

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

LitVar

Below is the list of publications found by LitVar. It may be empty.

Other links and lift over

dbSNP: rs121908728; hg19: chr20-43254234; API