rs757918826
Variant summary
Our verdict is Pathogenic. The variant received 16 ACMG points: 16P and 0B. PM2PM5PP3_StrongPP5_Very_Strong
The NM_000481.4(AMT):c.794G>A(p.Arg265His) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000143 in 1,613,960 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 Likely pathogenic (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R265C) has been classified as Likely pathogenic.
Frequency
Consequence
NM_000481.4 missense
Scores
Clinical Significance
Conservation
Publications
- glycine encephalopathyInheritance: AR Classification: DEFINITIVE, STRONG Submitted by: ClinGen, Labcorp Genetics (formerly Invitae), Myriad Women’s Health
- glycine encephalopathy 2Inheritance: AR Classification: DEFINITIVE Submitted by: G2P
- infantile glycine encephalopathyInheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
- neonatal glycine encephalopathyInheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
- atypical glycine encephalopathyInheritance: Unknown Classification: SUPPORTIVE Submitted by: Orphanet
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ACMG classification
Our verdict: Pathogenic. The variant received 16 ACMG points.
Transcripts
RefSeq
| Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | MANE | Protein | UniProt |
|---|---|---|---|---|---|---|---|---|
| AMT | NM_000481.4 | c.794G>A | p.Arg265His | missense_variant | Exon 7 of 9 | ENST00000273588.9 | NP_000472.2 |
Ensembl
| Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | TSL | MANE | Protein | Appris | UniProt |
|---|---|---|---|---|---|---|---|---|---|---|
| AMT | ENST00000273588.9 | c.794G>A | p.Arg265His | missense_variant | Exon 7 of 9 | 1 | NM_000481.4 | ENSP00000273588.3 | ||
| ENSG00000283189 | ENST00000636166.1 | c.1031G>A | p.Arg344His | missense_variant | Exon 9 of 11 | 5 | ENSP00000490106.1 |
Frequencies
GnomAD3 genomes AF: 0.0000263 AC: 4AN: 152146Hom.: 0 Cov.: 31 show subpopulations
GnomAD2 exomes AF: 0.0000159 AC: 4AN: 251324 AF XY: 0.0000147 show subpopulations
GnomAD4 exome AF: 0.0000130 AC: 19AN: 1461814Hom.: 0 Cov.: 31 AF XY: 0.0000165 AC XY: 12AN XY: 727210 show subpopulations
Age Distribution
GnomAD4 genome AF: 0.0000263 AC: 4AN: 152146Hom.: 0 Cov.: 31 AF XY: 0.0000135 AC XY: 1AN XY: 74334 show subpopulations
Age Distribution
ClinVar
Submissions by phenotype
Glycine encephalopathy Pathogenic:4
The variant is observed at an extremely low frequency in the gnomAD v2.1.1 dataset (total allele frequency: 0.002%). In silico tool predictions suggest damaging effect of the variant on gene or gene product (REVEL: 0.99; 3Cnet: 0.99). Same nucleotide change resulting in same amino acid change has been previously reported as pathogenic/likely pathogenic with strong evidence (ClinVar ID: VCV000550886 / PMID: 25231368). The variant has been observed in at least two similarly affected unrelated individuals (PMID: 25231368, 27362913). The variant has been reported to be in trans with a pathogenic variant as either compound heterozygous or homozygous in at least 2 similarly affected unrelated individuals (PMID: 27362913). A different missense change at the same codon (p.Arg265Cys) has been reported to be associated with AMT related disorder (PMID: 26371980). Therefore, this variant is classified as Pathogenic according to the recommendation of ACMG/AMP guideline. -
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For these reasons, this variant has been classified as Pathogenic. This variant disrupts the p.Arg265 amino acid residue in AMT. Other variant(s) that disrupt this residue have been observed in individuals with AMT-related conditions (PMID: 26371980, 27362913), which suggests that this may be a clinically significant amino acid residue. 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. ClinVar contains an entry for this variant (Variation ID: 550886). This missense change has been observed in individual(s) with glycine encephalopathy (PMID: 27362913). In at least one individual the data is consistent with being in trans (on the opposite chromosome) from a pathogenic variant. This variant is present in population databases (rs757918826, gnomAD 0.01%). This sequence change replaces arginine, which is basic and polar, with histidine, which is basic and polar, at codon 265 of the AMT protein (p.Arg265His). -
Variant summary: AMT c.794G>A (p.Arg265His) results in a non-conservative amino acid change located in the Aminomethyltransferase, folate-binding domain (IPR006222) of the encoded protein sequence. Five of five in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 1.6e-05 in 251324 control chromosomes. c.794G>A has been reported in the literature in multiple bi-alleleic individuals affected with Glycine Encephalopathy (Non-Ketotic Hyperglycinemia) (examples: Azize_2014, Coughlin_2017). These data indicate that the variant is very likely to be associated with disease. The following publications have been ascertained in the context of this evaluation (PMID: 25231368, 27362913). ClinVar contains an entry for this variant (Variation ID: 550886). Based on the evidence outlined above, the variant was classified as pathogenic. -
not provided Pathogenic:1
Not observed at significant frequency in large population cohorts (gnomAD); In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; This variant is associated with the following publications: (PMID: 27362913, 25231368, 27535533) -
Glycine encephalopathy 2 Pathogenic:1
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Glycine encephalopathy 1 Pathogenic:1
This submission and the accompanying classification are no longer maintained by the submitter. For more information on current observations and classification, please contact variantquestions@myriad.com. -
Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at