chr19-1398912-G-A

Position:

chr19-1398912-G-A

Variant summary

Our verdict is Likely benign. Variant got -5 ACMG points: 0P and 5B. BP4BS1

This summary comes from the ClinGen Evidence Repository: The NM_000156.6:c.570+4C>T variant in GAMT is an intronic variant affecting a nucleotide within the consensus splice site of intron 5. To our knowledge, this variant has not been reported in the literature and results of functional studies are unavailable. The highest population frequency in gnomAD v4.1.0. is 0.001148 (86/74912 alleles; no homozygotes) in the African / Afircan American population, which is higher than the ClinGen CCDS VCEP’s threshold for BS1 (>0.001), and therefore meets this criterion (BS1). The computational splicing predictor SpliceAI gives a score of 0.01 for donor loss and suggests that the variant has no impact on splicing (BP4). There is a ClinVar entry for this variant (Variation ID: 582572). In summary, this variant meets the criteria to be classified as likely benign for GAMT deficiency. GAMT-specific ACMG/AMP codes met, as specified by the ClinGen Cerebral Creatine Deficiency Syndromes VCEP (Specifications Version 2.0.0): BS1, BP4.(Classification approved by the ClinGen Creatine Deficiency Syndromes Variant Curation Expert Panel on September 11, 2024). LINK:https://erepo.genome.network/evrepo/ui/classification/CA9043611/MONDO:0012999/026

Frequency

Genomes: 𝑓 0.00035 ( 0 hom., cov: 32)

Exomes 𝑓: 0.000036 ( 0 hom. )

Consequence

GAMT
NM_000156.6 splice_donor_region, intron

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:4B:1

Conservation

PhyloP100: -1.55

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 -5 ACMG points.

BP4

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

BS1

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.570+4C>T		splice_donor_region_variant, intron_variant		ENST00000252288.8	NP_000147.1
GAMT	NM_138924.3 linkuse as main transcript	c.574C>T	p.Arg192Cys	missense_variant	5/5		NP_620279.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
GAMT	ENST00000252288.8 linkuse as main transcript	c.570+4C>T		splice_donor_region_variant, intron_variant		1	NM_000156.6	ENSP00000252288	P1	Q14353-1

Frequencies

GnomAD3 genomes

AF:

0.000355

AC:

AN:

152166

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00113

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.000327

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

GnomAD3 exomes

AF:

0.0000839

AC:

AN:

250176

Hom.:

AF XY:

0.0000590

AC XY:

AN XY:

135666

show subpopulations

Gnomad AFR exome

AF:

0.00112

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad SAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000266

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000363

AC:

AN:

1460992

Hom.:

Cov.:

AF XY:

0.0000385

AC XY:

AN XY:

726796

show subpopulations

Gnomad4 AFR exome

AF:

0.00116

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:

0.00000989

Gnomad4 OTH exome

AF:

0.0000497

GnomAD4 genome

AF:

0.000355

AC:

AN:

152166

Hom.:

Cov.:

AF XY:

0.000269

AC XY:

AN XY:

74326

show subpopulations

Gnomad4 AFR

AF:

0.00113

Gnomad4 AMR

AF:

0.000327

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

Alfa

AF:

0.000116

Hom.:

Bravo

AF:

0.000506

ESP6500AA

AF:

0.00295

AC:

ESP6500EA

AF:

0.00

AC:

ExAC

AF:

0.000107

AC:

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:4Benign:1

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

Deficiency of guanidinoacetate methyltransferase

Uncertain:2

Uncertain significance, no assertion criteria provided	clinical testing	Natera, Inc.	Sep 16, 2020	- -
Uncertain significance, criteria provided, single submitter	clinical testing	New York Genome Center	Sep 10, 2021	- -

Inborn genetic diseases

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Dec 16, 2017

The c.570+4C>T intronic variant results from a C to T substitution 4 nucleotides after coding exon 5 in the GAMT gene. This nucleotide position is not well conserved in available vertebrate species. Using two different splice site prediction tools, this alteration is predicted by BDGP to weaken the efficiency of the native splice donor site, but is not predicted to have a deleterious effect on this splice donor site by ESEfinder; however, direct evidence is unavailable. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -

Cerebral creatine deficiency syndrome

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Aug 10, 2022

This sequence change falls in intron 5 of the GAMT gene. It does not directly change the encoded amino acid sequence of the GAMT protein. It affects a nucleotide within the consensus splice site. This variant is present in population databases (rs199967562, gnomAD 0.1%). 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: 582572). Variants that disrupt the consensus splice site are a relatively common cause of aberrant splicing (PMID: 17576681, 9536098). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant is not likely to affect RNA splicing. 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. -

not provided

Benign:1

Benign, criteria provided, single submitter

clinical testing

GeneDx

Mar 03, 2015

- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

BayesDel_addAF

Benign

-0.39

BayesDel_noAF

Benign

-0.39

CADD

Benign

0.036

DANN

Benign

0.71

Eigen

Benign

-1.4

Eigen_PC

Benign

-1.7

FATHMM_MKL

Benign

0.0047

LIST_S2

Benign

0.41

M_CAP

Uncertain

0.14

MetaRNN

Benign

0.023

MetaSVM

Uncertain

-0.18

MutationTaster

Benign

1.0

N;N

PrimateAI

Benign

0.29

PROVEAN

Benign

-0.20

REVEL

Uncertain

0.35

Sift

Uncertain

0.0030

Sift4G

Benign

0.077

Vest4

0.063

MVP

0.46

MPC

0.20

ClinPred

0.021

GERP RS

-6.7

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.0

gMVP

0.61

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.080

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