3-49417665-C-G

Position:

• chr3-49417665-C-G

Variant summary

Our verdict is Likely pathogenic. Variant got 7 ACMG points: 7P and 0B. PM2 PP3_Strong PP5

The NM_000481.4(AMT):​c.1087G>C​(p.Gly363Arg) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. 12/21 in silico tools predict a damaging outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

• Frequency: Genomes: not found (cov: 32)
• Consequence: AMT NM_000481.4 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:2 U:2
• Conservation: PhyloP100: 7.78

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]

ENSG00000283189 (HGNC:):

ACMG classification

Verdict is Likely_pathogenic. Variant got 7 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.966
• PP5: Variant 3-49417665-C-G is Pathogenic according to our data. Variant chr3-49417665-C-G is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 554115.We mark this variant Likely_pathogenic, oryginal submissions are: {Uncertain_significance=2, Pathogenic=1, Likely_pathogenic=1}. Variant chr3-49417665-C-G is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
AMT	NM_000481.4	c.1087G>C	p.Gly363Arg	missense_variant	9/9	ENST00000273588.9	NP_000472.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
AMT	ENST00000273588.9	c.1087G>C	p.Gly363Arg	missense_variant	9/9	1	NM_000481.4	ENSP00000273588.3
ENSG00000283189	ENST00000636166.1	c.1324G>C	p.Gly442Arg	missense_variant	11/11	5		ENSP00000490106.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

Bravo AF: 0.00000378

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:2 Uncertain:2

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Glycine encephalopathy Pathogenic:2 Uncertain:1

Pathogenic, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Dec 20, 2023	This sequence change replaces glycine, which is neutral and non-polar, with arginine, which is basic and polar, at codon 363 of the AMT protein (p.Gly363Arg). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individual(s) with glycine encephalopathy (PMID: 27362913; Invitae). In at least one individual the data is consistent with being in trans (on the opposite chromosome) from a pathogenic variant. ClinVar contains an entry for this variant (Variation ID: 554115). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is expected to disrupt AMT protein function with a positive predictive value of 95%. For these reasons, this variant has been classified as Pathogenic. -
Uncertain significance, criteria provided, single submitter	clinical testing	Counsyl	Sep 26, 2017	- -
Likely pathogenic, criteria provided, single submitter	clinical testing	Baylor Genetics	May 15, 2023	- -

not specified Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Oct 09, 2023

Variant summary: AMT c.1087G>C (p.Gly363Arg) results in a non-conservative amino acid change located in the Glycine cleavage T-protein, C-terminal barrel domain (IPR013977) of the encoded protein sequence. Five of five in-silico tools predict a damaging effect of the variant on protein function. The variant was absent in 251358 control chromosomes (gnomAD). The available data on variant occurrences in the general population are insufficient to allow any conclusion about variant significance. c.1087G>C has been reported in the literature in an individual(s) affected with Glycine Encephalopathy (Non-Ketotic Hyperglycinemia) without strong evidence of causality (Coughlin_2017). This report does not provide unequivocal conclusions about association of the variant with Glycine Encephalopathy (Non-Ketotic Hyperglycinemia). To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. The following publication has been ascertained in the context of this evaluation (PMID: 27362913). Two submitters have cited clinical-significance assessments for this variant to ClinVar after 2014. One submitter classified the variant as pathogenic, and one submitter classified the variant as uncertain significance. Based on the evidence outlined above, the variant was classified as uncertain significance. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.99
BayesDel_addAF	Pathogenic	0.45	D
BayesDel_noAF	Pathogenic	0.41
CADD	Pathogenic	29
DANN	Pathogenic	1.0
DEOGEN2	Pathogenic	0.94	D;T;.;.;D;T;T;T;.;.;D;T;.;.
Eigen	Pathogenic	0.84
Eigen_PC	Pathogenic	0.69
FATHMM_MKL	Pathogenic	0.97	D
LIST_S2	Pathogenic	1.0	D;D;D;D;D;D;D;D;D;D;D;D;D;D
M_CAP	Pathogenic	0.46	D
MetaRNN	Pathogenic	0.97	D;D;D;D;D;D;D;D;D;D;D;D;D;D
MetaSVM	Pathogenic	0.86	D
MutationAssessor	Pathogenic	4.3	H;.;H;.;.;.;.;.;.;.;.;.;.;.
PrimateAI	Uncertain	0.77	T
PROVEAN	Pathogenic	-6.3	D;.;D;D;.;.;.;.;.;.;.;.;.;.
REVEL	Pathogenic	0.94
Sift	Pathogenic	0.0	D;.;D;D;.;.;.;.;.;.;.;.;.;.
Sift4G	Pathogenic	0.0010	D;.;D;D;.;.;.;.;.;.;.;.;.;.
Polyphen		1.0	D;.;.;.;.;.;.;.;.;.;.;.;.;.
Vest4		0.98
MutPred		0.82		Loss of ubiquitination at K358 (P = 0.0345);.;Loss of ubiquitination at K358 (P = 0.0345);.;.;.;.;.;.;.;.;.;.;.;
MVP		0.94
MPC		0.88
ClinPred		1.0	D
GERP RS		4.8
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.99
gMVP		0.98

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.020		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: rs1167886830; hg19: chr3-49455098;