19-1397469-C-T

Variant names:

Variant summary

Our verdict is Uncertain significance. The variant received 4 ACMG points: 4P and 0B. PM1PM2

The NM_000156.6(GAMT):c.601G>A(p.Gly201Ser) variant causes a missense change. The variant allele was found at a frequency of 0.0000423 in 1,608,028 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. G201R) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.000020 ( 0 hom., cov: 33)

Exomes 𝑓: 0.000045 ( 0 hom. )

Consequence

GAMT
NM_000156.6 missense

Scores

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:4

Conservation

PhyloP100: 4.72

Publications

1 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

GAMT links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Uncertain_significance. The variant received 4 ACMG points.

PM1

In a hotspot region, there are 3 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 3 benign, 18 uncertain in NM_000156.6

PM2

Very rare variant in population databases, with high coverage;

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000156.6. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	GAMT	NM_000156.6	MANE Select	c.601G>A	p.Gly201Ser	missense	Exon 6 of 6	NP_000147.1

Ensembl Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein
GAMT	ENST00000252288.8	TSL:1 MANE Select	c.601G>A	p.Gly201Ser	missense	Exon 6 of 6	ENSP00000252288.1
GAMT	ENST00000640762.1	TSL:5	c.532G>A	p.Gly178Ser	missense	Exon 6 of 6	ENSP00000492031.1
GAMT	ENST00000640164.1	TSL:2	n.434G>A		non_coding_transcript_exon	Exon 4 of 4

Frequencies

GnomAD3 genomes

AF:

0.0000197

AC:

AN:

152252

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.000196

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:

0.00

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.0000285

AC:

AN:

245286

AF XY:

0.0000375

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.0000869

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.0000577

Gnomad NFE exome

AF:

0.0000178

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000447

AC:

AN:

1455658

Hom.:

Cov.:

AF XY:

0.0000331

AC XY:

AN XY:

724384

show subpopulations

African (AFR)

AF:

0.0000299

AC:

AN:

33476

American (AMR)

AF:

0.0000671

AC:

AN:

44712

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26120

East Asian (EAS)

AF:

0.00

AC:

AN:

39692

South Asian (SAS)

AF:

0.0000232

AC:

AN:

86256

European-Finnish (FIN)

AF:

0.00

AC:

AN:

47438

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5766

European-Non Finnish (NFE)

AF:

0.0000522

AC:

AN:

1111856

Other (OTH)

AF:

0.0000166

AC:

AN:

60342

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.484

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:

0.0000197

AC:

AN:

152370

Hom.:

Cov.:

AF XY:

0.0000268

AC XY:

AN XY:

74512

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

41580

American (AMR)

AF:

0.000196

AC:

AN:

15312

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.00

AC:

AN:

5194

South Asian (SAS)

AF:

0.00

AC:

AN:

4832

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10632

Middle Eastern (MID)

AF:

0.00

AC:

AN:

294

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

68028

Other (OTH)

AF:

0.00

AC:

AN:

2114

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.508

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Alfa

AF:

0.00

Hom.:

Bravo

AF:

0.0000302

ExAC

AF:

0.0000247

AC:

EpiCase

AF:

0.0000545

EpiControl

AF:

0.000119

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:4

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Deficiency of guanidinoacetate methyltransferase

Uncertain:2

Mar 24, 2020

Natera, Inc.

Significance:Uncertain significance

Review Status:no assertion criteria provided

Collection Method:clinical testing

Jan 12, 2018

Illumina Laboratory Services, Illumina

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score, this variant could not be ruled out of causing disease and therefore its association with disease required further investigation. A literature search was performed for the gene, cDNA change, and amino acid change (if applicable). No publications were found based on this search. This variant was therefore classified as a variant of unknown significance for this disease.

not provided

Uncertain:1

Apr 02, 2023

GeneDx

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Not observed at significant frequency in large population cohorts (gnomAD); 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

Cerebral creatine deficiency syndrome

Uncertain:1

Sep 07, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change replaces glycine, which is neutral and non-polar, with serine, which is neutral and polar, at codon 201 of the GAMT protein (p.Gly201Ser). This variant is present in population databases (rs540554423, gnomAD 0.01%). 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: 205589). 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: "Tolerated"; PolyPhen-2: "Probably Damaging"; Align-GVGD: "Class C0"). 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 v4.9

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.30

BayesDel_addAF

Uncertain

0.070

BayesDel_noAF

Uncertain

0.060

CADD

Pathogenic

(source)

DANN

Uncertain

1.0

DEOGEN2

Pathogenic

0.84

Eigen

Uncertain

0.66

Eigen_PC

Uncertain

0.55

FATHMM_MKL

Uncertain

0.96

LIST_S2

Uncertain

0.89

M_CAP

Pathogenic

0.35

MetaRNN

Uncertain

0.52

MetaSVM

Pathogenic

1.0

MutationAssessor

Pathogenic

3.4

PhyloP100

4.7

PROVEAN

Uncertain

-3.2

REVEL

Pathogenic

0.67

Sift

Benign

0.11

Sift4G

Benign

0.095

Polyphen

1.0

Vest4

0.40

MutPred

0.39

Gain of phosphorylation at G201 (P = 0.0652)

MVP

0.97

ClinPred

0.66

GERP RS

5.1

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.7

Varity_R

0.44

Mutation Taster

=40/60

disease causing

(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

Variant Effect in Transcripts

RefSeq Transcripts

Ensembl Transcripts

Frequencies

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over