NM_000156.6:c.392-7C>T

Variant names:

Variant summary

Our verdict is Benign. The variant received -13 ACMG points: 0P and 13B. BS2BA1BP4

This summary comes from the ClinGen Evidence Repository: The NM_000156.6:c.392-7C>T variant in GAMT is a nucleotide substitution in intron 3. The highest population minor allele frequency in gnomAD v2.1.1 is 0.00430 (107/24892 alleles) in the African population, which is higher than the ClinGen CCDS VCEP’s threshold for BA1 (>0.003), and therefore meets this criterion (BA1). There are 4 homozygotes in gnomAD v2.1.1 (all in the S Asian population) which, given the early onset and severity of phenotype for GAMT deficiency, supporting that the variant is not associated with GAMT deficiency. Computational evidence from SpliceAI and varSEAK suggests no impact on the gene/gene product (BP4). There is a ClinVar entry for this variant (Variation ID: 137436,). In summary, this variant meets the criteria to be classified as Benign for GAMT deficiency based on the ACMG/AMP criteria applied, as specified by the ClinGen Cerebral Creatine Deficiency Syndromes Variant Curation Expert Panel (Specifications Version 1.1.0): BA1, BS2, BP4.(Classification approved by the ClinGen CCDS VCEP on June 6, 2022). LINK:https://erepo.genome.network/evrepo/ui/classification/CA291019/MONDO:0012999/026

Frequency

Genomes: 𝑓 0.0015 ( 1 hom., cov: 32)

Exomes 𝑓: 0.00038 ( 8 hom. )

Consequence

GAMT
NM_000156.6 splice_region, intron

Scores

Splicing: ADA: 0.00003445

Clinical Significance

Benign reviewed by expert panel B:8

Conservation

PhyloP100: -1.99

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

GAMT links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Benign. The variant received -13 ACMG points.

BP4

For more information check the summary or visit ClinGen Evidence Repository.

BS2

For more information check the summary or visit ClinGen Evidence Repository.

BA1

For more information check the summary or visit ClinGen Evidence Repository.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
GAMT	NM_000156.6 link	c.392-7C>T		splice_region_variant, intron_variant	Intron 3 of 5	ENST00000252288.8	NP_000147.1	Q14353-1V9HWB2
GAMT	NM_138924.3 link	c.392-7C>T		splice_region_variant, intron_variant	Intron 3 of 4		NP_620279.1	Q14353-2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
GAMT	ENST00000252288.8 link	c.392-7C>T		splice_region_variant, intron_variant	Intron 3 of 5	1	NM_000156.6	ENSP00000252288.1		Q14353-1

Frequencies

GnomAD3 genomes

AF:

0.00145

AC:

221

AN:

152176

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00456

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.000523

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.00352

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.0000441

Gnomad OTH

AF:

0.00191

GnomAD2 exomes

AF:

0.000662

AC:

166

AN:

250786

AF XY:

0.000736

show subpopulations

Gnomad AFR exome

AF:

0.00426

Gnomad AMR exome

AF:

0.000202

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000618

Gnomad OTH exome

AF:

0.000490

GnomAD4 exome

AF:

0.000383

AC:

559

AN:

1461118

Hom.:

Cov.:

AF XY:

0.000453

AC XY:

329

AN XY:

726880

show subpopulations

African (AFR)

AF:

0.00493

AC:

165

AN:

33480

American (AMR)

AF:

0.000179

AC:

AN:

44720

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26136

East Asian (EAS)

AF:

0.0000252

AC:

AN:

39698

South Asian (SAS)

AF:

0.00276

AC:

238

AN:

86246

European-Finnish (FIN)

AF:

0.00

AC:

AN:

52718

Middle Eastern (MID)

AF:

0.00104

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

0.0000944

AC:

105

AN:

1111970

Other (OTH)

AF:

0.000596

AC:

AN:

60382

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.461

Heterozygous variant carriers

121

161

201

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Exome Hom

Variant carriers

100

<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:

0.00145

AC:

221

AN:

152294

Hom.:

Cov.:

AF XY:

0.00150

AC XY:

112

AN XY:

74468

show subpopulations

African (AFR)

AF:

0.00455

AC:

189

AN:

41546

American (AMR)

AF:

0.000523

AC:

AN:

15304

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.00

AC:

AN:

5178

South Asian (SAS)

AF:

0.00352

AC:

AN:

4826

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10626

Middle Eastern (MID)

AF:

0.00

AC:

AN:

294

European-Non Finnish (NFE)

AF:

0.0000441

AC:

AN:

68022

Other (OTH)

AF:

0.00189

AC:

AN:

2114

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.497

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:

0.000961

Hom.:

Bravo

AF:

0.00128

Asia WGS

AF:

0.00115

AC:

AN:

3476

EpiCase

AF:

0.0000545

EpiControl

AF:

0.00

ClinVar

Significance: Benign

Submissions summary: Benign:8

Revision: reviewed by expert panel

LINK: link

Submissions by phenotype

not specified

Benign:3

Apr 10, 2017

Eurofins Ntd Llc (ga)

Significance:Benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Nov 21, 2013

GeneDx

Significance:Benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This variant is considered likely benign or benign based on one or more of the following criteria: it is a conservative change, it occurs at a poorly conserved position in the protein, it is predicted to be benign by multiple in silico algorithms, and/or has population frequency not consistent with disease. -

Jun 14, 2019

Genetic Services Laboratory, University of Chicago

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Deficiency of guanidinoacetate methyltransferase

Benign:3

Jan 12, 2018

Illumina Laboratory Services, Illumina

Significance:Likely benign

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 and internal cut-off values, a variant classified as likely benign is not then subjected to further curation. The score for this variant resulted in a classification of likely benign for this disease. -

Jun 06, 2022

ClinGen Cerebral Creatine Deficiency Syndromes Variant Curation Expert Panel, ClinGen

Significance:Benign

Review Status:reviewed by expert panel

Collection Method:curation

The NM_000156.6:c.392-7C>T variant in GAMT is a nucleotide substitution in intron 3. The highest population minor allele frequency in gnomAD v2.1.1 is 0.00430 (107/24892 alleles) in the African population, which is higher than the ClinGen CCDS VCEP’s threshold for BA1 (>0.003), and therefore meets this criterion (BA1). There are 4 homozygotes in gnomAD v2.1.1 (all in the S Asian population) which, given the early onset and severity of phenotype for GAMT deficiency, supporting that the variant is not associated with GAMT deficiency. Computational evidence from SpliceAI and varSEAK suggests no impact on the gene/gene product (BP4). There is a ClinVar entry for this variant (Variation ID: 137436,). In summary, this variant meets the criteria to be classified as Benign for GAMT deficiency based on the ACMG/AMP criteria applied, as specified by the ClinGen Cerebral Creatine Deficiency Syndromes Variant Curation Expert Panel (Specifications Version 1.1.0): BA1, BS2, BP4. (Classification approved by the ClinGen CCDS VCEP on June 6, 2022). -

Jan 05, 2020

Natera, Inc.

Significance:Benign

Review Status:no assertion criteria provided

Collection Method:clinical testing

- -

not provided

Benign:1

Jul 01, 2023

CeGaT Center for Human Genetics Tuebingen

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

GAMT: BP4, BS2 -

Cerebral creatine deficiency syndrome

Benign:1

Jan 30, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

BayesDel_noAF

Benign

-0.86

CADD

Benign

0.18

(source)

DANN

Benign

0.74

PhyloP100

-2.0

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.1

Mutation Taster

=100/0

polymorphism

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

dbscSNV1_ADA

Benign

0.000034

dbscSNV1_RF

Benign

0.0

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