6-42960816-G-A

Variant summary

Our verdict is Uncertain significance. Variant got 3 ACMG points: 3P and 0B. PM2PP3

The NM_018960.6(GNMT):c.49G>A(p.Gly17Arg) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000308 in 1,557,362 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★).

Frequency

Genomes: 𝑓 0.000033 ( 0 hom., cov: 34)

Exomes 𝑓: 0.000031 ( 0 hom. )

Consequence

GNMT
NM_018960.6 missense

Scores

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:2

Conservation

PhyloP100: 9.44

Variant links:

Genes affected

GNMT (HGNC:4415): (glycine N-methyltransferase) The protein encoded by this gene is an enzyme that catalyzes the conversion of S-adenosyl-L-methionine (along with glycine) to S-adenosyl-L-homocysteine and sarcosine. This protein is found in the cytoplasm and acts as a homotetramer. Defects in this gene are a cause of GNMT deficiency (hypermethioninemia). Alternative splicing results in multiple transcript variants. Naturally occurring readthrough transcription occurs between the upstream CNPY3 (canopy FGF signaling regulator 3) gene and this gene and is represented with GeneID:107080644. [provided by RefSeq, Jan 2016]

GNMT links:

CNPY3-GNMT (HGNC:):

CNPY3-GNMT links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Uncertain_significance. Variant got 3 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

PP3

MetaRNN computational evidence supports a deleterious effect, 0.806

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
GNMT	NM_018960.6 linkuse as main transcript	c.49G>A	p.Gly17Arg	missense_variant	1/6	ENST00000372808.4
CNPY3-GNMT	NR_134890.2 linkuse as main transcript	n.340-1946G>A		intron_variant, non_coding_transcript_variant

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
GNMT	ENST00000372808.4 linkuse as main transcript	c.49G>A	p.Gly17Arg	missense_variant	1/6	1	NM_018960.6	P1

Frequencies

GnomAD3 genomes

AF:

0.0000328

AC:

AN:

152246

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000241

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:

0.0000588

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.0000250

AC:

AN:

160274

Hom.:

AF XY:

0.0000345

AC XY:

AN XY:

86926

show subpopulations

Gnomad AFR exome

AF:

0.000115

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad SAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000462

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000306

AC:

AN:

1405116

Hom.:

Cov.:

AF XY:

0.0000317

AC XY:

AN XY:

694180

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.00

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.00

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.0000368

Gnomad4 OTH exome

AF:

0.0000172

GnomAD4 genome

AF:

0.0000328

AC:

AN:

152246

Hom.:

Cov.:

AF XY:

0.0000538

AC XY:

AN XY:

74376

show subpopulations

Gnomad4 AFR

AF:

0.0000241

Gnomad4 AMR

AF:

0.00

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.0000588

Gnomad4 OTH

AF:

0.00

Bravo

AF:

0.0000151

ExAC

AF:

0.0000261

AC:

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

not specified

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Jun 18, 2021

The c.49G>A (p.G17R) alteration is located in exon 1 (coding exon 1) of the GNMT gene. This alteration results from a G to A substitution at nucleotide position 49, causing the glycine (G) at amino acid position 17 to be replaced by an arginine (R). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

not provided

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Jan 03, 2024

This sequence change replaces glycine, which is neutral and non-polar, with arginine, which is basic and polar, at codon 17 of the GNMT protein (p.Gly17Arg). 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 variant has not been reported in the literature in individuals affected with GNMT-related conditions. ClinVar contains an entry for this variant (Variation ID: 2072206). An algorithm developed to predict the effect of missense changes on protein structure and function (PolyPhen-2) suggests that this variant is likely to be disruptive. 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

AlphaMissense

Pathogenic

0.96

BayesDel_addAF

Pathogenic

0.34

BayesDel_noAF

Pathogenic

0.25

Cadd

Pathogenic

Dann

Pathogenic

1.0

DEOGEN2

Pathogenic

0.85

Eigen

Pathogenic

0.88

Eigen_PC

Pathogenic

0.83

FATHMM_MKL

Pathogenic

0.98

LIST_S2

Uncertain

0.97

M_CAP

Pathogenic

0.56

MetaRNN

Pathogenic

0.81

MetaSVM

Uncertain

-0.076

MutationAssessor

Uncertain

2.4

MutationTaster

Benign

1.0

PrimateAI

Pathogenic

0.88

PROVEAN

Pathogenic

-5.7

REVEL

Uncertain

0.64

Sift

Uncertain

0.0030

Sift4G

Pathogenic

0.0

Polyphen

1.0

Vest4

0.69

MutPred

0.38

Gain of MoRF binding (P = 0.0428);

MVP

0.86

MPC

2.5

ClinPred

0.97

GERP RS

4.8

Varity_R

0.86

gMVP

0.86

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

LitVar

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

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over