rs386833523

Variant summary

Our verdict is Likely pathogenic. The variant received 6 ACMG points: 6P and 0B. PM2PM5PP3_Moderate

The NM_000170.3(GLDC):​c.1319T>C​(p.Ile440Thr) 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. 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. I440N) has been classified as Likely pathogenic.

Frequency

Genomes: not found (cov: 32)
Exomes 𝑓: 0.0000014 ( 0 hom. )
Failed GnomAD Quality Control

Consequence

GLDC
NM_000170.3 missense

Scores

7
9
3

Clinical Significance

Uncertain significance criteria provided, single submitter U:1

Conservation

PhyloP100: 8.21

Publications

4 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: Likely_pathogenic. The variant received 6 ACMG points.

PM2
Very rare variant in population databases, with high coverage;
PM5
Other missense variant is known to change same aminoacid residue: Variant chr9-6592933-A-T is described in ClinVar as Likely_pathogenic. ClinVar VariationId is 56042.Status of the report is no_assertion_criteria_provided, 0 stars.
PP3
MetaRNN computational evidence supports a deleterious effect, 0.935

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
GLDCNM_000170.3 linkc.1319T>C p.Ile440Thr missense_variant Exon 10 of 25 ENST00000321612.8 NP_000161.2 P23378

Ensembl

Gene Transcript HGVSc HGVSp Effect Exon rank TSL MANE Protein Appris UniProt
GLDCENST00000321612.8 linkc.1319T>C p.Ile440Thr missense_variant Exon 10 of 25 1 NM_000170.3 ENSP00000370737.4 P23378

Frequencies

GnomAD3 genomes
Cov.:
32
GnomAD4 exome
Data not reliable, filtered out with message: AS_VQSR
AF:
0.00000137
AC:
2
AN:
1461788
Hom.:
0
Cov.:
31
AF XY:
0.00
AC XY:
0
AN XY:
727210
show subpopulations
⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.
African (AFR)
AF:
0.00
AC:
0
AN:
33480
American (AMR)
AF:
0.00
AC:
0
AN:
44724
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
26132
East Asian (EAS)
AF:
0.00
AC:
0
AN:
39698
South Asian (SAS)
AF:
0.00
AC:
0
AN:
86258
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
53420
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
5768
European-Non Finnish (NFE)
AF:
0.00000180
AC:
2
AN:
1111920
Other (OTH)
AF:
0.00
AC:
0
AN:
60388
⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0.000081), which strongly suggests a high chance of mosaicism in these individuals.
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.300
Heterozygous variant carriers
0
0
1
1
2
2
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance

Age Distribution

Exome 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
GnomAD4 genome
Cov.:
32

ClinVar

Significance: Uncertain significance
Submissions summary: Uncertain:1
Revision: criteria provided, single submitter
LINK: link

Submissions by phenotype

Glycine encephalopathy Uncertain:1
Apr 23, 2018
Labcorp Genetics (formerly Invitae), Labcorp
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

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. Algorithms developed to predict the effect of missense changes on protein structure and function do not agree on the potential impact of this missense change (SIFT: "Deleterious"; PolyPhen-2: "Benign"; Align-GVGD: "Class C0"). This variant has not been reported in the literature in individuals with GLDC-related disease. This variant is not present in population databases (ExAC no frequency). This sequence change replaces isoleucine with threonine at codon 440 of the GLDC protein (p.Ile440Thr). The isoleucine residue is moderately conserved and there is a moderate physicochemical difference between isoleucine and threonine. -

Computational scores

Source: dbNSFP v4.3

Name
Calibrated prediction
Score
Prediction
AlphaMissense
Pathogenic
0.83
BayesDel_addAF
Pathogenic
0.25
D
BayesDel_noAF
Uncertain
0.12
CADD
Uncertain
24
DANN
Uncertain
1.0
DEOGEN2
Uncertain
0.74
D
Eigen
Uncertain
0.30
Eigen_PC
Uncertain
0.44
FATHMM_MKL
Pathogenic
0.99
D
LIST_S2
Pathogenic
0.98
D
M_CAP
Uncertain
0.14
D
MetaRNN
Pathogenic
0.94
D
MetaSVM
Uncertain
0.75
D
MutationAssessor
Benign
1.8
L
PhyloP100
8.2
PrimateAI
Benign
0.42
T
PROVEAN
Uncertain
-3.7
D
REVEL
Pathogenic
0.77
Sift
Uncertain
0.0010
D
Sift4G
Pathogenic
0.0010
D
Polyphen
0.053
B
Vest4
0.83
MutPred
0.76
Loss of stability (P = 0.0425);
MVP
0.99
MPC
0.079
ClinPred
0.99
D
GERP RS
5.7
Varity_R
0.75
gMVP
0.86
Mutation Taster
=34/66
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: rs386833523; hg19: chr9-6592933; API