chr20-34928893-T-C

Variant names:

Variant summary

Our verdict is Likely benign. The variant received -2 ACMG points: 2P and 4B. PM2BP4_Strong

The NM_000178.4(GSS):c.1360A>G(p.Ile454Val) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000124 in 1,613,892 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 17/22 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★). Synonymous variant affecting the same amino acid position (i.e. I454I) has been classified as Likely benign.

Frequency

Genomes: 𝑓 0.0000066 ( 0 hom., cov: 31)

Exomes 𝑓: 6.8e-7 ( 0 hom. )

Consequence

GSS
NM_000178.4 missense

Scores

Clinical Significance

Uncertain significance criteria provided, single submitter U:1

Conservation

PhyloP100: 0.346

Publications

0 publications found

Variant links:

Genes affected

GSS (HGNC:4624): (glutathione synthetase) Glutathione is important for a variety of biological functions, including protection of cells from oxidative damage by free radicals, detoxification of xenobiotics, and membrane transport. The protein encoded by this gene functions as a homodimer to catalyze the second step of glutathione biosynthesis, which is the ATP-dependent conversion of gamma-L-glutamyl-L-cysteine to glutathione. Defects in this gene are a cause of glutathione synthetase deficiency. [provided by RefSeq, Jul 2008]

GSS Gene-Disease associations (from GenCC):

inherited glutathione synthetase deficiency
Inheritance: AR Classification: DEFINITIVE Submitted by: ClinGen
glutathione synthetase deficiency with 5-oxoprolinuria
Inheritance: AR Classification: STRONG Submitted by: Labcorp Genetics (formerly Invitae)

GSS links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Likely_benign. The variant received -2 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

BP4

Computational evidence support a benign effect (MetaRNN=0.066943705).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
GSS	NM_000178.4 link	c.1360A>G	p.Ile454Val	missense_variant	Exon 13 of 13	ENST00000651619.1	NP_000169.1	P48637-1V9HWJ1
GSS	NM_001322494.1 link	c.1360A>G	p.Ile454Val	missense_variant	Exon 13 of 13		NP_001309423.1	P48637-1V9HWJ1
GSS	NM_001322495.1 link	c.1360A>G	p.Ile454Val	missense_variant	Exon 13 of 13		NP_001309424.1	P48637-1V9HWJ1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
GSS	ENST00000651619.1 link	c.1360A>G	p.Ile454Val	missense_variant	Exon 13 of 13		NM_000178.4	ENSP00000498303.1		P48637-1

Frequencies

GnomAD3 genomes

AF:

0.00000657

AC:

AN:

152166

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:

0.0000147

Gnomad OTH

AF:

0.00

GnomAD4 exome

AF:

6.84e-7

AC:

AN:

1461726

Hom.:

Cov.:

AF XY:

0.00000138

AC XY:

AN XY:

727158

show subpopulations

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

African (AFR)

AF:

0.00

AC:

AN:

33476

American (AMR)

AF:

0.00

AC:

AN:

44724

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26136

East Asian (EAS)

AF:

0.00

AC:

AN:

39700

South Asian (SAS)

AF:

0.00

AC:

AN:

86250

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53418

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5640

European-Non Finnish (NFE)

AF:

8.99e-7

AC:

AN:

1112000

Other (OTH)

AF:

0.00

AC:

AN:

60382

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0.000000), which strongly suggests a high chance of mosaicism in these individuals.

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.375

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

GnomAD4 genome

AF:

0.00000657

AC:

AN:

152166

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

74334

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

41424

American (AMR)

AF:

0.00

AC:

AN:

15278

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3466

East Asian (EAS)

AF:

0.00

AC:

AN:

5192

South Asian (SAS)

AF:

0.00

AC:

AN:

4830

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10626

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.0000147

AC:

AN:

68028

Other (OTH)

AF:

0.00

AC:

AN:

2094

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:

0.00

Hom.:

Bravo

AF:

0.00000378

EpiCase

AF:

0.0000545

EpiControl

AF:

0.00

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

LINK: link

Submissions by phenotype

Inborn genetic diseases

Uncertain:1

May 20, 2025

Ambry Genetics

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The c.1360A>G (p.I454V) alteration is located in exon 13 (coding exon 12) of the GSS gene. This alteration results from a A to G substitution at nucleotide position 1360, causing the isoleucine (I) at amino acid position 454 to be replaced by a valine (V). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.060

BayesDel_addAF

Benign

-0.099

BayesDel_noAF

Benign

-0.38

CADD

Benign

(source)

DANN

Benign

0.80

DEOGEN2

Uncertain

0.43

.;T;T;T;.

Eigen

Benign

-0.60

Eigen_PC

Benign

-0.43

FATHMM_MKL

Benign

0.55

LIST_S2

Benign

0.76

.;.;.;T;T

M_CAP

Benign

0.014

MetaRNN

Benign

0.067

T;T;T;T;T

MetaSVM

Benign

-0.67

MutationAssessor

Benign

0.79

.;N;N;N;.

PhyloP100

0.35

PrimateAI

Benign

0.26

PROVEAN

Benign

0.060

.;N;.;.;N

REVEL

Benign

0.12

Sift

Benign

1.0

.;T;.;.;T

Sift4G

Benign

0.39

.;T;.;.;T

Polyphen

0.0

.;B;B;B;.

Vest4

0.022, 0.14

MutPred

0.39

.;Gain of ubiquitination at K452 (P = 0.068);Gain of ubiquitination at K452 (P = 0.068);Gain of ubiquitination at K452 (P = 0.068);.;

MVP

0.64

MPC

0.17

ClinPred

0.060

GERP RS

2.6

Varity_R

0.072

gMVP

0.66

Mutation Taster

=81/19

polymorphism

(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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chr20-34928893-T-C

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