rs1052014497

chr3-49419018-A-Gchr3-49419018-A-T

Variant summary

Our verdict is Likely pathogenic. Variant got 6 ACMG points: 6P and 0B. PM1 PM2 PP3_Moderate

The NM_000481.4(AMT):c.830T>C(p.Ile277Thr) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000062 in 1,613,744 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. I277N) has been classified as Uncertain significance.

• Frequency:
  • Genomes: 𝑓 0.000020 (0 hom., cov: 31)
  • Exomes 𝑓: 0.0000048 (0 hom.)
• Consequence: AMT NM_000481.4 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:3
• Conservation: PhyloP100: 8.81

Genes affected

AMT (HGNC:473): (aminomethyltransferase) This gene encodes one of four critical components of the glycine cleavage system. Mutations in this gene have been associated with glycine encephalopathy. Multiple transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Sep 2011]

ACMG classification

Verdict is Likely_pathogenic. Variant got 6 ACMG points.

• PM1: In a hotspot region, there are 3 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 1 benign, 5 uncertain in NM_000481.4
• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.939

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
AMT	NM_000481.4	c.830T>C	p.Ile277Thr	missense_variant	7/9	ENST00000273588.9

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
AMT	ENST00000273588.9	c.830T>C	p.Ile277Thr	missense_variant	7/9	1	NM_000481.4	P1

Frequencies

GnomAD3 genomes AF: 0.0000197 AC: 3 AN: 151926 Hom.: 0 Cov.: 31

Gnomad AFR AF: 0.0000242

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.0000656

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

GnomAD3 exomes AF: 0.00000398 AC: 1 AN: 251364 Hom.: 0 AF XY: 0.00000736 AC XY: 1 AN XY: 135886

Gnomad AFR exome AF: 0.00

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: 0.00

Gnomad OTH exome AF: 0.000163

GnomAD4 exome AF: 0.00000479 AC: 7 AN: 1461818 Hom.: 0 Cov.: 31 AF XY: 0.00000825 AC XY: 6 AN XY: 727210

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.0000224

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.0000116

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00000360

Gnomad4 OTH exome AF: 0.0000166

GnomAD4 genome AF: 0.0000197 AC: 3 AN: 151926 Hom.: 0 Cov.: 31 AF XY: 0.0000135 AC XY: 1 AN XY: 74172

Gnomad4 AFR AF: 0.0000242

Gnomad4 AMR AF: 0.0000656

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.0000147

Gnomad4 OTH AF: 0.00

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:3

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Non-ketotic hyperglycinemia Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	Invitae	Sep 01, 2021	This sequence change replaces isoleucine with threonine at codon 277 of the AMT protein (p.Ile277Thr). The isoleucine residue is highly conserved and there is a moderate physicochemical difference between isoleucine and threonine. This variant is not present in population databases (ExAC no frequency). This variant has not been reported in the literature in individuals affected with AMT-related conditions. Algorithms developed to predict the effect of missense changes on protein structure and function (SIFT, PolyPhen-2, Align-GVGD) all suggest that this variant is likely to be disruptive. 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. -
Uncertain significance, no assertion criteria provided	clinical testing	Natera, Inc.	Oct 05, 2021	- -

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Athena Diagnostics

Mar 06, 2018

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.70
BayesDel_addAF	Pathogenic	0.41	D
BayesDel_noAF	Pathogenic	0.35
Cadd	Pathogenic	26
Dann	Uncertain	1.0
DEOGEN2	Pathogenic	0.82	D;T;.;.;D;T;T;.;.;D;T;.;.
Eigen	Pathogenic	0.80
Eigen_PC	Pathogenic	0.77
FATHMM_MKL	Uncertain	0.91	D
LIST_S2	Pathogenic	1.0	D;D;D;D;D;D;D;D;D;D;D;D;D
M_CAP	Pathogenic	0.47	D
MetaRNN	Pathogenic	0.94	D;D;D;D;D;D;D;D;D;D;D;D;D
MetaSVM	Uncertain	0.37	D
MutationAssessor	Pathogenic	3.5	M;.;M;.;.;.;.;.;.;.;.;.;.
MutationTaster	Benign	1.0	D;D;D;D;D
PrimateAI	Uncertain	0.77	T
PROVEAN	Pathogenic	-4.4	D;.;D;D;.;.;.;.;.;.;.;.;.
REVEL	Pathogenic	0.90
Sift	Uncertain	0.0010	D;.;D;D;.;.;.;.;.;.;.;.;.
Sift4G	Uncertain	0.052	T;.;D;T;.;.;.;.;.;.;.;.;.
Polyphen		0.97	D;.;.;.;.;.;.;.;.;.;.;.;.
Vest4		0.92
MutPred		0.77		Loss of stability (P = 0.0074);.;Loss of stability (P = 0.0074);.;.;Loss of stability (P = 0.0074);.;.;.;.;.;.;.;
MVP		0.92
MPC		0.85
ClinPred		1.0	D
GERP RS		5.3
Varity_R		0.78
gMVP		0.96

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

Other links and lift over

dbSNP: rs1052014497; hg19: chr3-49456451;