19-1399180-G-T

Variant names:

Variant summary

Our verdict is Pathogenic. The variant received 10 ACMG points: 10P and 0B. PM1PM2PM5PP3_Strong

The NM_000156.6(GAMT):c.407C>A(p.Thr136Lys) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000657 in 152,320 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. T136M) has been classified as Pathogenic.

Frequency

Genomes: 𝑓 0.0000066 ( 0 hom., cov: 33)

Consequence

GAMT
NM_000156.6 missense

Scores

Clinical Significance

Not reported in ClinVar

Conservation

PhyloP100: 7.97

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: Pathogenic. The variant received 10 ACMG points.

PM1

In a hotspot region, there are 4 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 9 uncertain in NM_000156.6

PM2

Very rare variant in population databases, with high coverage;

PM5

Other missense variant is known to change same aminoacid residue: Variant chr19-1399180-G-A is described in ClinVar as Pathogenic. ClinVar VariationId is 544257.Status of the report is reviewed_by_expert_panel, 3 stars.

PP3

MetaRNN computational evidence supports a deleterious effect, 0.952

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.407C>A	p.Thr136Lys	missense	Exon 4 of 6	NP_000147.1
	GAMT	NM_138924.3		c.407C>A	p.Thr136Lys	missense	Exon 4 of 5	NP_620279.1

Ensembl Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein
GAMT	ENST00000252288.8	TSL:1 MANE Select	c.407C>A	p.Thr136Lys	missense	Exon 4 of 6	ENSP00000252288.1
GAMT	ENST00000447102.8	TSL:2	c.407C>A	p.Thr136Lys	missense	Exon 4 of 5	ENSP00000403536.2
GAMT	ENST00000640762.1	TSL:5	c.338C>A	p.Thr113Lys	missense	Exon 4 of 6	ENSP00000492031.1

Frequencies

GnomAD3 genomes

AF:

0.00000657

AC:

AN:

152202

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.0000654

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:

0.00000398

AC:

AN:

251062

AF XY:

0.00000736

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.0000289

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

Cov.:

GnomAD4 genome

AF:

0.00000657

AC:

AN:

152320

Hom.:

Cov.:

AF XY:

0.0000134

AC XY:

AN XY:

74474

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

41558

American (AMR)

AF:

0.0000653

AC:

AN:

15306

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.00

AC:

AN:

5186

South Asian (SAS)

AF:

0.00

AC:

AN:

4828

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10624

Middle Eastern (MID)

AF:

0.00

AC:

AN:

294

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

68026

Other (OTH)

AF:

0.00

AC:

AN:

2114

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.675

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Alfa

AF:

0.00

Hom.:

ExAC

AF:

0.00000824

AC:

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Pathogenic

0.97

BayesDel_addAF

Pathogenic

0.42

BayesDel_noAF

Pathogenic

0.45

CADD

Pathogenic

(source)

DANN

Uncertain

0.99

DEOGEN2

Pathogenic

0.92

Eigen

Uncertain

0.67

Eigen_PC

Uncertain

0.53

FATHMM_MKL

Pathogenic

0.99

LIST_S2

Uncertain

0.91

M_CAP

Pathogenic

0.73

MetaRNN

Pathogenic

0.95

MetaSVM

Pathogenic

1.1

MutationAssessor

Pathogenic

3.4

PhyloP100

8.0

PrimateAI

Uncertain

0.68

PROVEAN

Pathogenic

-5.4

REVEL

Pathogenic

0.98

Sift

Uncertain

0.0020

Sift4G

Uncertain

0.015

Polyphen

1.0

Vest4

0.95

MutPred

0.77

Gain of methylation at T136 (P = 0.0168)

MVP

0.99

MPC

0.69

ClinPred

0.98

GERP RS

4.0

Varity_R

0.91

gMVP

0.92

Mutation Taster

=19/81

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

ClinVar

Computational scores

Splicing

Publications

Other links and lift over