rs781693346

Variant summary

Our verdict is Uncertain significance. The variant received 2 ACMG points: 2P and 0B. PM1

The NM_000170.3(GLDC):​c.2518A>G​(p.Met840Val) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000179 in 1,613,780 control chromosomes in the GnomAD database, with no homozygous occurrence. 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. M840K) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.000099 ( 0 hom., cov: 32)
Exomes 𝑓: 0.00019 ( 0 hom. )

Consequence

GLDC
NM_000170.3 missense

Scores

6
8
4

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:9

Conservation

PhyloP100: 7.48

Publications

1 publications found
Variant links:
Genes affected
GLDC (HGNC:4313): (glycine decarboxylase) Degradation of glycine is brought about by the glycine cleavage system, which is composed of four mitochondrial protein components: P protein (a pyridoxal phosphate-dependent glycine decarboxylase), H protein (a lipoic acid-containing protein), T protein (a tetrahydrofolate-requiring enzyme), and L protein (a lipoamide dehydrogenase). The protein encoded by this gene is the P protein, which binds to glycine and enables the methylamine group from glycine to be transferred to the T protein. Defects in this gene are a cause of nonketotic hyperglycinemia (NKH).[provided by RefSeq, Jan 2010]
GLDC Gene-Disease associations (from GenCC):
  • glycine encephalopathy
    Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: Myriad Women’s Health, Labcorp Genetics (formerly Invitae), ClinGen
  • glycine encephalopathy 1
    Inheritance: AR Classification: DEFINITIVE Submitted by: G2P
  • infantile glycine encephalopathy
    Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
  • neonatal glycine encephalopathy
    Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
  • atypical glycine encephalopathy
    Inheritance: Unknown Classification: SUPPORTIVE Submitted by: Orphanet

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Uncertain_significance. The variant received 2 ACMG points.

PM1
In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 10 uncertain in NM_000170.3

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
GLDCNM_000170.3 linkc.2518A>G p.Met840Val missense_variant Exon 21 of 25 ENST00000321612.8 NP_000161.2

Ensembl

Gene Transcript HGVSc HGVSp Effect Exon rank TSL MANE Protein Appris UniProt
GLDCENST00000321612.8 linkc.2518A>G p.Met840Val missense_variant Exon 21 of 25 1 NM_000170.3 ENSP00000370737.4

Frequencies

GnomAD3 genomes
AF:
0.0000985
AC:
15
AN:
152214
Hom.:
0
Cov.:
32
show subpopulations
Gnomad AFR
AF:
0.0000724
Gnomad AMI
AF:
0.00
Gnomad AMR
AF:
0.0000655
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:
0.000162
Gnomad OTH
AF:
0.00
GnomAD2 exomes
AF:
0.0000795
AC:
20
AN:
251490
AF XY:
0.0000883
show subpopulations
Gnomad AFR exome
AF:
0.00
Gnomad AMR exome
AF:
0.0000289
Gnomad ASJ exome
AF:
0.00
Gnomad EAS exome
AF:
0.000217
Gnomad FIN exome
AF:
0.00
Gnomad NFE exome
AF:
0.000123
Gnomad OTH exome
AF:
0.000163
GnomAD4 exome
AF:
0.000187
AC:
274
AN:
1461566
Hom.:
0
Cov.:
30
AF XY:
0.000171
AC XY:
124
AN XY:
727130
show subpopulations
African (AFR)
AF:
0.0000299
AC:
1
AN:
33474
American (AMR)
AF:
0.0000224
AC:
1
AN:
44724
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
26134
East Asian (EAS)
AF:
0.000327
AC:
13
AN:
39698
South Asian (SAS)
AF:
0.00
AC:
0
AN:
86250
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
53416
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
5766
European-Non Finnish (NFE)
AF:
0.000222
AC:
247
AN:
1111718
Other (OTH)
AF:
0.000199
AC:
12
AN:
60386
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.457
Heterozygous variant carriers
0
15
30
44
59
74
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance

Age Distribution

Exome Het
Variant carriers
0
20
40
60
80
100
<30
30-35
35-40
40-45
45-50
50-55
55-60
60-65
65-70
70-75
75-80
>80
Age
GnomAD4 genome
AF:
0.0000985
AC:
15
AN:
152214
Hom.:
0
Cov.:
32
AF XY:
0.0000941
AC XY:
7
AN XY:
74360
show subpopulations
African (AFR)
AF:
0.0000724
AC:
3
AN:
41462
American (AMR)
AF:
0.0000655
AC:
1
AN:
15276
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
3470
East Asian (EAS)
AF:
0.00
AC:
0
AN:
5198
South Asian (SAS)
AF:
0.00
AC:
0
AN:
4832
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
10622
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
316
European-Non Finnish (NFE)
AF:
0.000162
AC:
11
AN:
68034
Other (OTH)
AF:
0.00
AC:
0
AN:
2092
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.538
Heterozygous variant carriers
0
1
2
3
4
5
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance

Age Distribution

Genome Het
Variant carriers
0
2
4
6
8
10
<30
30-35
35-40
40-45
45-50
50-55
55-60
60-65
65-70
70-75
75-80
>80
Age
Alfa
AF:
0.000203
Hom.:
0
Bravo
AF:
0.000125
TwinsUK
AF:
0.00
AC:
0
ALSPAC
AF:
0.000259
AC:
1
ExAC
AF:
0.0000330
AC:
4
EpiCase
AF:
0.000273
EpiControl
AF:
0.0000593

ClinVar

Significance: Uncertain significance
Submissions summary: Uncertain:9
Revision: criteria provided, multiple submitters, no conflicts
LINK: link

Submissions by phenotype

Glycine encephalopathy Uncertain:5
Jan 05, 2020
Natera, Inc.
Significance:Uncertain significance
Review Status:no assertion criteria provided
Collection Method:clinical testing

Jan 13, 2018
Illumina Laboratory Services, Illumina
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score, this variant could not be ruled out of causing disease and therefore its association with disease required further investigation. A literature search was performed for the gene, cDNA change, and amino acid change (if applicable). No publications were found based on this search. This variant was therefore classified as a variant of unknown significance for this disease.

Aug 02, 2018
Baylor Genetics
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

This variant was determined to be of uncertain significance according to ACMG Guidelines, 2015 [PMID:25741868].

Sep 01, 2022
Labcorp Genetics (formerly Invitae), Labcorp
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

This sequence change replaces methionine, which is neutral and non-polar, with valine, which is neutral and non-polar, at codon 840 of the GLDC protein (p.Met840Val). This variant is present in population databases (rs781693346, gnomAD 0.02%). This variant has not been reported in the literature in individuals affected with GLDC-related conditions. ClinVar contains an entry for this variant (Variation ID: 367180). 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 GLDC protein function. 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.

Aug 16, 2021
Fulgent Genetics, Fulgent Genetics
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

not provided Uncertain:2
Breakthrough Genomics, Breakthrough Genomics
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:not provided

Apr 24, 2024
GeneDx
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; Has not been previously published as pathogenic or benign to our knowledge

Inborn genetic diseases Uncertain:1
Apr 03, 2024
Ambry Genetics
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

The c.2518A>G (p.M840V) alteration is located in exon 21 (coding exon 21) of the GLDC gene. This alteration results from a A to G substitution at nucleotide position 2518, causing the methionine (M) at amino acid position 840 to be replaced by a valine (V). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear.

Glycine encephalopathy 1 Uncertain:1
Jul 30, 2021
Department of Pathology and Laboratory Medicine, Sinai Health System
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:research

Computational scores

Source: dbNSFP v4.3

Name
Calibrated prediction
Score
Prediction
AlphaMissense
Benign
0.15
BayesDel_addAF
Uncertain
0.16
D
BayesDel_noAF
Pathogenic
0.28
CADD
Uncertain
25
DANN
Uncertain
0.99
DEOGEN2
Uncertain
0.67
D;.;.;.
Eigen
Uncertain
0.60
Eigen_PC
Uncertain
0.57
FATHMM_MKL
Pathogenic
0.97
D
LIST_S2
Pathogenic
0.98
D;D;D;D
M_CAP
Pathogenic
0.34
D
MetaRNN
Uncertain
0.68
D;D;D;D
MetaSVM
Pathogenic
1.0
D
MutationAssessor
Benign
1.6
L;.;.;.
PhyloP100
7.5
PrimateAI
Uncertain
0.65
T
PROVEAN
Uncertain
-3.3
D;.;.;.
REVEL
Pathogenic
0.83
Sift
Benign
0.32
T;.;.;.
Sift4G
Benign
0.24
T;.;.;.
Vest4
0.88
ClinPred
0.27
T
GERP RS
4.7
Varity_R
0.59
gMVP
0.92
Mutation Taster
=19/81
disease causing

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

Other links and lift over

dbSNP: rs781693346; hg19: chr9-6550854; COSMIC: COSV58681225; API