chr19-1398977-T-G

Variant names:

Variant summary

Our verdict is Likely pathogenic. The variant received 6 ACMG points: 6P and 0B. PM1PM2PP3_Moderate

The NM_000156.6(GAMT):c.509A>C(p.Asn170Thr) variant causes a missense change. The variant allele was found at a frequency of 0.00000806 in 1,613,024 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 (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. N170S) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.000026 ( 0 hom., cov: 32)

Exomes 𝑓: 0.0000062 ( 0 hom. )

Consequence

GAMT
NM_000156.6 missense

Scores

Clinical Significance

Uncertain significance criteria provided, single submitter U:2

Conservation

PhyloP100: 4.78

Publications

3 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: Likely_pathogenic. The variant received 6 ACMG points.

PM1

In a hotspot region, there are 6 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 17 uncertain in NM_000156.6

PM2

Very rare variant in population databases, with high coverage;

PP3

MetaRNN computational evidence supports a deleterious effect, 0.85

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
GAMT	NM_000156.6 link	c.509A>C	p.Asn170Thr	missense_variant	Exon 5 of 6	ENST00000252288.8	NP_000147.1	Q14353-1V9HWB2
GAMT	NM_138924.3 link	c.509A>C	p.Asn170Thr	missense_variant	Exon 5 of 5		NP_620279.1	Q14353-2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
GAMT	ENST00000252288.8 link	c.509A>C	p.Asn170Thr	missense_variant	Exon 5 of 6	1	NM_000156.6	ENSP00000252288.1		Q14353-1

Frequencies

GnomAD3 genomes

AF:

0.0000263

AC:

AN:

151876

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.000197

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

GnomAD2 exomes

AF:

0.0000120

AC:

AN:

250906

AF XY:

0.00

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.0000579

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00000882

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000616

AC:

AN:

1461148

Hom.:

Cov.:

AF XY:

0.00000413

AC XY:

AN XY:

726874

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33480

American (AMR)

AF:

0.0000447

AC:

AN:

44720

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:

86258

European-Finnish (FIN)

AF:

0.00

AC:

AN:

52714

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

0.00000630

AC:

AN:

1111986

Other (OTH)

AF:

0.00

AC:

AN:

60386

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.481

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:

0.0000263

AC:

AN:

151876

Hom.:

Cov.:

AF XY:

0.0000135

AC XY:

AN XY:

74198

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

41330

American (AMR)

AF:

0.000197

AC:

AN:

15250

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3470

East Asian (EAS)

AF:

0.00

AC:

AN:

5182

South Asian (SAS)

AF:

0.00

AC:

AN:

4808

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10604

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.0000147

AC:

AN:

67918

Other (OTH)

AF:

0.00

AC:

AN:

2086

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.450

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Genome 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

Alfa

AF:

0.00

Hom.:

Bravo

AF:

0.0000189

ExAC

AF:

0.00000824

AC:

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, single submitter

LINK: link

Submissions by phenotype

Cerebral creatine deficiency syndrome

Uncertain:1

Feb 04, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change replaces asparagine, which is neutral and polar, with threonine, which is neutral and polar, at codon 170 of the GAMT protein (p.Asn170Thr). This variant is present in population databases (rs202199674, gnomAD 0.009%). 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: 664322). 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: "Possibly 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. -

Deficiency of guanidinoacetate methyltransferase

Uncertain:1

Aug 10, 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

Pathogenic

0.85

BayesDel_addAF

Uncertain

0.018

BayesDel_noAF

Uncertain

-0.040

CADD

Pathogenic

(source)

DANN

Uncertain

1.0

DEOGEN2

Pathogenic

0.81

D;.;.

Eigen

Uncertain

0.66

Eigen_PC

Uncertain

0.56

FATHMM_MKL

Pathogenic

0.98

LIST_S2

Uncertain

0.90

D;D;D

M_CAP

Pathogenic

0.63

MetaRNN

Pathogenic

0.85

D;D;D

MetaSVM

Uncertain

0.70

MutationAssessor

Pathogenic

3.2

M;.;M

PhyloP100

4.8

PrimateAI

Uncertain

0.66

PROVEAN

Uncertain

-3.4

D;.;D

REVEL

Pathogenic

0.85

Sift

Benign

0.083

T;.;D

Sift4G

Benign

0.12

T;.;T

Polyphen

1.0

D;.;.

Vest4

0.84

MutPred

0.67

Loss of helix (P = 0.079);.;Loss of helix (P = 0.079);

MVP

0.92

MPC

0.63

ClinPred

0.97

GERP RS

4.0

Varity_R

0.63

gMVP

0.83

Mutation Taster

=38/62

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

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over