rs765070826

Variant summary

Our verdict is Uncertain significance. The variant received 2 ACMG points: 2P and 0B. PM1

The NM_000156.6(GAMT):​c.292C>T​(p.Arg98Trp) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000448 in 1,584,670 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R98Q) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.000033 ( 0 hom., cov: 32)
Exomes 𝑓: 0.000046 ( 0 hom. )

Consequence

GAMT
NM_000156.6 missense

Scores

9
9
1

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:6

Conservation

PhyloP100: 0.723

Publications

0 publications found
Variant links:
Genes affected
GAMT (HGNC:4136): (guanidinoacetate N-methyltransferase) The protein encoded by this gene is a methyltransferase that converts guanidoacetate to creatine, using S-adenosylmethionine as the methyl donor. Defects in this gene have been implicated in neurologic syndromes and muscular hypotonia, probably due to creatine deficiency and accumulation of guanidinoacetate in the brain of affected individuals. Two transcript variants encoding different isoforms have been described for this gene. Pseudogenes of this gene are found on chromosomes 2 and 13. [provided by RefSeq, Feb 2012]
GAMT Gene-Disease associations (from GenCC):
  • guanidinoacetate methyltransferase deficiency
    Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Orphanet, G2P, Labcorp Genetics (formerly Invitae), ClinGen, Ambry Genetics

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Uncertain_significance. The variant received 2 ACMG points.

PM1
In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 2 benign, 16 uncertain in NM_000156.6

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
GAMTNM_000156.6 linkc.292C>T p.Arg98Trp missense_variant Exon 2 of 6 ENST00000252288.8 NP_000147.1 Q14353-1V9HWB2
GAMTNM_138924.3 linkc.292C>T p.Arg98Trp missense_variant Exon 2 of 5 NP_620279.1 Q14353-2

Ensembl

Gene Transcript HGVSc HGVSp Effect Exon rank TSL MANE Protein Appris UniProt
GAMTENST00000252288.8 linkc.292C>T p.Arg98Trp missense_variant Exon 2 of 6 1 NM_000156.6 ENSP00000252288.1 Q14353-1

Frequencies

GnomAD3 genomes
AF:
0.0000329
AC:
5
AN:
152170
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:
0.000207
Gnomad FIN
AF:
0.00
Gnomad MID
AF:
0.00
Gnomad NFE
AF:
0.0000588
Gnomad OTH
AF:
0.00
GnomAD2 exomes
AF:
0.0000690
AC:
14
AN:
202910
AF XY:
0.0000639
show subpopulations
Gnomad AFR exome
AF:
0.00
Gnomad AMR exome
AF:
0.000134
Gnomad ASJ exome
AF:
0.00
Gnomad EAS exome
AF:
0.000261
Gnomad FIN exome
AF:
0.00
Gnomad NFE exome
AF:
0.0000453
Gnomad OTH exome
AF:
0.00
GnomAD4 exome
AF:
0.0000461
AC:
66
AN:
1432500
Hom.:
0
Cov.:
33
AF XY:
0.0000493
AC XY:
35
AN XY:
710144
show subpopulations
African (AFR)
AF:
0.0000304
AC:
1
AN:
32892
American (AMR)
AF:
0.0000982
AC:
4
AN:
40724
Ashkenazi Jewish (ASJ)
AF:
0.0000392
AC:
1
AN:
25518
East Asian (EAS)
AF:
0.000392
AC:
15
AN:
38222
South Asian (SAS)
AF:
0.0000608
AC:
5
AN:
82292
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
49634
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
5732
European-Non Finnish (NFE)
AF:
0.0000364
AC:
40
AN:
1098206
Other (OTH)
AF:
0.00
AC:
0
AN:
59280
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.490
Heterozygous variant carriers
0
4
8
11
15
19
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance

Age Distribution

Exome Het
Variant carriers
0
4
8
12
16
20
<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:
0.0000329
AC:
5
AN:
152170
Hom.:
0
Cov.:
32
AF XY:
0.0000538
AC XY:
4
AN XY:
74330
show subpopulations
African (AFR)
AF:
0.00
AC:
0
AN:
41438
American (AMR)
AF:
0.00
AC:
0
AN:
15292
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
3472
East Asian (EAS)
AF:
0.00
AC:
0
AN:
5180
South Asian (SAS)
AF:
0.000207
AC:
1
AN:
4828
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
10614
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
316
European-Non Finnish (NFE)
AF:
0.0000588
AC:
4
AN:
68028
Other (OTH)
AF:
0.00
AC:
0
AN:
2090
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.515
Heterozygous variant carriers
0
1
1
2
2
3
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance

Age Distribution

Genome Het
Variant carriers
0
2
4
6
8
10
<30
30-35
35-40
40-45
45-50
50-55
55-60
60-65
65-70
70-75
75-80
>80
Age
Alfa
AF:
0.000103
Hom.:
0
Bravo
AF:
0.0000529
TwinsUK
AF:
0.000270
AC:
1
ALSPAC
AF:
0.00
AC:
0
ExAC
AF:
0.0000582
AC:
7
Asia WGS
AF:
0.000289
AC:
1
AN:
3478

ClinVar

Significance: Uncertain significance
Submissions summary: Uncertain:6
Revision: criteria provided, multiple submitters, no conflicts
LINK: link

Submissions by phenotype

not provided Uncertain:3
Jun 23, 2017
Center for Pediatric Genomic Medicine, Children's Mercy Hospital and Clinics
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

Jan 04, 2019
Athena Diagnostics
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

Jul 11, 2025
GeneDx
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; Has not been previously published as pathogenic or benign to our knowledge -

Inborn genetic diseases Uncertain:1
Feb 21, 2024
Ambry Genetics
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

The c.292C>T (p.R98W) alteration is located in exon 2 (coding exon 2) of the GAMT gene. This alteration results from a C to T substitution at nucleotide position 292, causing the arginine (R) at amino acid position 98 to be replaced by a tryptophan (W). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

Cerebral creatine deficiency syndrome Uncertain:1
Sep 06, 2022
Labcorp Genetics (formerly Invitae), Labcorp
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

This sequence change replaces arginine, which is basic and polar, with tryptophan, which is neutral and slightly polar, at codon 98 of the GAMT protein (p.Arg98Trp). 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 GAMT-related conditions. ClinVar contains an entry for this variant (Variation ID: 431854). Algorithms developed to predict the effect of missense changes on protein structure and function are either unavailable or do not agree on the potential impact of this missense change (SIFT: "Deleterious"; PolyPhen-2: "Probably Damaging"; Align-GVGD: "Class C15"). 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. -

Deficiency of guanidinoacetate methyltransferase Uncertain:1
Jan 24, 2020
Natera, Inc.
Significance:Uncertain significance
Review Status:no assertion criteria provided
Collection Method:clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name
Calibrated prediction
Score
Prediction
AlphaMissense
Uncertain
0.35
BayesDel_addAF
Pathogenic
0.27
D
BayesDel_noAF
Pathogenic
0.14
CADD
Pathogenic
27
DANN
Pathogenic
1.0
DEOGEN2
Pathogenic
0.88
D;.;.
Eigen
Uncertain
0.53
Eigen_PC
Uncertain
0.43
FATHMM_MKL
Uncertain
0.89
D
LIST_S2
Uncertain
0.96
D;D;D
M_CAP
Pathogenic
0.62
D
MetaRNN
Uncertain
0.60
D;D;D
MetaSVM
Pathogenic
0.80
D
MutationAssessor
Pathogenic
3.4
M;.;M
PhyloP100
0.72
PrimateAI
Uncertain
0.62
T
PROVEAN
Pathogenic
-5.3
D;.;D
REVEL
Pathogenic
0.77
Sift
Uncertain
0.0060
D;.;D
Sift4G
Uncertain
0.0090
D;.;D
Polyphen
1.0
D;.;.
Vest4
0.93
MutPred
0.50
Loss of catalytic residue at R98 (P = 0.0336);.;Loss of catalytic residue at R98 (P = 0.0336);
MVP
0.95
MPC
0.64
ClinPred
0.72
D
GERP RS
3.1
PromoterAI
0.0091
Neutral
RBP_binding_hub_radar
0.0
RBP_regulation_power_radar
1.7
Varity_R
0.53
gMVP
0.87
Mutation Taster
=20/80
disease causing

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

Other links and lift over

dbSNP: rs765070826; hg19: chr19-1399827; API