19-1401438-G-T

Position:

chr19-1401438-G-T

Variant summary

Our verdict is Likely benign. Variant got -1 ACMG points: 1P and 2B. BP4PM2_SupportingBP7

This summary comes from the ClinGen Evidence Repository: The NM_000156.6:c.39C>A (p.Gly13=) variant in GAMT is a synonymous variant in exon 1. It is absent in gnomAD v2.1.1 (PM2_Supporting); however, this region has low coverage and, therefore, the allele frequency data may not be accurate. It is predicted to not impact splicing by SpliceAI and VarSeak, and the nucleotide is not highly conserved (BP4, BP7). This variant does not appear to have been reported in the published literature. It is noted in ClinVar (Variation ID: 544263). Although this variant may be rare, it has been classified as likely benign by the ClinGen Creatine Deficiency Syndromes (CCDS) Variant Curation Expert Panel (VCEP) based on the recommendation of Richards et al (PMID:25741868) because it is a synonymous variant, the altered nucleotide is not highly conserved, computational prediction suggests no impact on splicing, and there is no additional evidence to suggest that the variant is disease-causing. GAMT-specific ACMG/AMP criteria applied, as specified by the CCDS VCEP (Specifications Version 1.1.0): PM2_Supporting, BP4, BP7.(Classification approved by the ClinGen CCDS VCEP on June 6, 2022). LINK:https://erepo.genome.network/evrepo/ui/classification/CA504731736/MONDO:0012999/026

Frequency

Genomes: 𝑓 0.000013 ( 0 hom., cov: 32)

Exomes 𝑓: 0.000036 ( 0 hom. )

Consequence

GAMT
ENST00000252288.8 synonymous

Scores

Clinical Significance

Likely benign reviewed by expert panel B:3

Conservation

PhyloP100: 0.0100

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 links:

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ACMG classification

Classification made for transcript

Verdict is Likely_benign. Variant got -1 ACMG points.

PM2

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

BP4

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

BP7

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

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
GAMT	NM_000156.6 linkuse as main transcript	c.39C>A	p.Gly13=	synonymous_variant	1/6	ENST00000252288.8	NP_000147.1
GAMT	NM_138924.3 linkuse as main transcript	c.39C>A	p.Gly13=	synonymous_variant	1/5		NP_620279.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
GAMT	ENST00000252288.8 linkuse as main transcript	c.39C>A	p.Gly13=	synonymous_variant	1/6	1	NM_000156.6	ENSP00000252288	P1	Q14353-1
GAMT	ENST00000447102.8 linkuse as main transcript	c.39C>A	p.Gly13=	synonymous_variant	1/5	2		ENSP00000403536		Q14353-2
GAMT	ENST00000640762.1 linkuse as main transcript	c.39C>A	p.Gly13=	synonymous_variant	1/6	5		ENSP00000492031

Frequencies

GnomAD3 genomes

AF:

0.0000132

AC:

AN:

152056

Hom.:

Cov.:

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:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.0000294

Gnomad OTH

AF:

0.00

GnomAD4 exome

AF:

0.0000357

AC:

AN:

1260138

Hom.:

Cov.:

AF XY:

0.0000324

AC XY:

AN XY:

617538

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:

0.0000404

Gnomad4 OTH exome

AF:

0.0000772

GnomAD4 genome

AF:

0.0000132

AC:

AN:

152056

Hom.:

Cov.:

AF XY:

0.0000135

AC XY:

AN XY:

74274

show subpopulations

Gnomad4 AFR

AF:

0.00

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:

0.0000294

Gnomad4 OTH

AF:

0.00

Bravo

AF:

0.0000113

ClinVar

Significance: Likely benign

Submissions summary: Benign:3

Revision: reviewed by expert panel

LINK: link

Submissions by phenotype

Inborn genetic diseases

Benign:1

Likely benign, criteria provided, single submitter

clinical testing

Ambry Genetics

Oct 10, 2019

This alteration is classified as likely benign based on a combination of the following: seen in unaffected individuals, population frequency, intact protein function, lack of segregation with disease, co-occurrence, RNA analysis, in silico models, amino acid conservation, lack of disease association in case-control studies, and/or the mechanism of disease or impacted region is inconsistent with a known cause of pathogenicity. -

Cerebral creatine deficiency syndrome

Benign:1

Likely benign, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Jan 17, 2024

- -

Deficiency of guanidinoacetate methyltransferase

Benign:1

Likely benign, reviewed by expert panel

curation

ClinGen Cerebral Creatine Deficiency Syndromes Variant Curation Expert Panel, ClinGen

Jun 06, 2022

The NM_000156.6:c.39C>A (p.Gly13=) variant in GAMT is a synonymous variant in exon 1. It is absent in gnomAD v2.1.1 (PM2_Supporting); however, this region has low coverage and, therefore, the allele frequency data may not be accurate. It is predicted to not impact splicing by SpliceAI and VarSeak, and the nucleotide is not highly conserved (BP4, BP7). This variant does not appear to have been reported in the published literature. It is noted in ClinVar (Variation ID: 544263). Although this variant may be rare, it has been classified as likely benign by the ClinGen Creatine Deficiency Syndromes (CCDS) Variant Curation Expert Panel (VCEP) based on the recommendation of Richards et al (PMID: 25741868) because it is a synonymous variant, the altered nucleotide is not highly conserved, computational prediction suggests no impact on splicing, and there is no additional evidence to suggest that the variant is disease-causing. GAMT-specific ACMG/AMP criteria applied, as specified by the CCDS VCEP (Specifications Version 1.1.0): PM2_Supporting, BP4, BP7. (Classification approved by the ClinGen CCDS VCEP on June 6, 2022). -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

BayesDel_noAF

Benign

-0.43

CADD

Benign

DANN

Benign

0.94

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.7

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