rs386833587

chr9-6605186-G-A

Variant summary

Our verdict is Pathogenic. Variant got 16 ACMG points: 16P and 0B. PM1 PM2 PP3_Strong PP5_Very_Strong

The NM_000170.3(GLDC):c.806C>T(p.Thr269Met) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000036 in 1,613,244 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 (★★). Synonymous variant affecting the same amino acid position (i.e. T269T) has been classified as Likely benign.

• Frequency:
  • Genomes: 𝑓 0.000013 (0 hom., cov: 32)
  • Exomes 𝑓: 0.000038 (0 hom.)
• Consequence: GLDC NM_000170.3 missense
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:11 O:1
• Conservation: PhyloP100: 7.46

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]

ACMG classification

Verdict is Pathogenic. Variant got 16 ACMG points.

• PM1: In a hotspot region, there are 3 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 8 uncertain in NM_000170.3
• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.981
• PP5: Variant 9-6605186-G-A is Pathogenic according to our data. Variant chr9-6605186-G-A is described in ClinVar as [Likely_pathogenic]. Clinvar id is 56104.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr9-6605186-G-A is described in Lovd as [Pathogenic]. Variant chr9-6605186-G-A is described in Lovd as [Likely_pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
GLDC	NM_000170.3	c.806C>T	p.Thr269Met	missense_variant	6/25	ENST00000321612.8

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
GLDC	ENST00000321612.8	c.806C>T	p.Thr269Met	missense_variant	6/25	1	NM_000170.3	P1

Frequencies

GnomAD3 genomes AF: 0.0000132 AC: 2 AN: 151986 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.0000242

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

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: 0.0000159 AC: 4 AN: 251468 Hom.: 0 AF XY: 0.0000294 AC XY: 4 AN XY: 135906

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: 0.0000653

Gnomad FIN exome AF: 0.0000462

Gnomad NFE exome AF: 0.00000879

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.0000383 AC: 56 AN: 1461258 Hom.: 0 Cov.: 31 AF XY: 0.0000385 AC XY: 28 AN XY: 727004

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.0000232

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.0000450

Gnomad4 OTH exome AF: 0.0000663

GnomAD4 genome AF: 0.0000132 AC: 2 AN: 151986 Hom.: 0 Cov.: 32 AF XY: 0.0000135 AC XY: 1 AN XY: 74222

Gnomad4 AFR AF: 0.0000242

Gnomad4 AMR AF: 0.00

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

Alfa AF: 0.0000278 Hom.: 0

Bravo AF: 0.0000113

ExAC AF: 0.00000824 AC: 1

EpiCase AF: 0.0000545

EpiControl AF: 0.00

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:11 Other:1

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Non-ketotic hyperglycinemia Pathogenic:7 Other:1

Pathogenic, criteria provided, single submitter	clinical testing	Fulgent Genetics, Fulgent Genetics	Aug 03, 2021	- -
Likely pathogenic, no assertion criteria provided	literature only	Juha Muilu Group; Institute for Molecular Medicine Finland (FIMM)	-	- -
Pathogenic, no assertion criteria provided	clinical testing	Natera, Inc.	Sep 16, 2020	- -
not provided, no classification provided	phenotyping only	GenomeConnect - Brain Gene Registry	-	Variant classified as Pathogenic and reported on 07-23-2022 by GeneDx. Assertions are reported exactly as they appear on the patient provided laboratory report. GenomeConnect does not attempt to reinterpret the variant. The IDDRC-CTSA National Brain Gene Registry (BGR) is a study funded by the U.S. National Center for Advancing Translational Sciences (NCATS) and includes 13 Intellectual and Developmental Disability Research Center (IDDRC) institutions. The study is led by Principal Investigator Dr. Philip Payne from Washington University. The BGR is a data commons of gene variants paired with subject clinical information. This database helps scientists learn more about genetic changes and their impact on the brain and behavior. Participation in the Brain Gene Registry requires participation in GenomeConnect. More information about the Brain Gene Registry can be found on the study website - https://braingeneregistry.wustl.edu/. -
Pathogenic, criteria provided, single submitter	clinical testing	Invitae	Jan 31, 2024	This sequence change replaces threonine, which is neutral and polar, with methionine, which is neutral and non-polar, at codon 269 of the GLDC protein (p.Thr269Met). This variant is present in population databases (rs386833587, gnomAD 0.006%). This missense change has been observed in individual(s) with nonketotic hyperglycinemia (PMID: 16450403, 16601880, 27362913). ClinVar contains an entry for this variant (Variation ID: 56104). 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 not expected to disrupt GLDC protein function with a negative predictive value of 80%. Experimental studies have shown that this missense change affects GLDC function (PMID: 26179960). For these reasons, this variant has been classified as Pathogenic. -
Likely pathogenic, criteria provided, single submitter	clinical testing	Counsyl	Aug 16, 2017	- -
Pathogenic, criteria provided, single submitter	clinical testing	Genetics and Molecular Pathology, SA Pathology	Jul 07, 2023	The GLDC c.806C>T variant is classified as PATHOGENIC (PS3, PS4, PP3) The GLDC c.806C>T variant is a single nucleotide change in exon 6/25 of the GLDC gene, which is predicted to change the amino acid threonine at position 269 in the protein to methionine. This variant has been reported in both homozygous and compound heterozygous state in multiple individuals with Glycine encephalopathy (PMID:16450403, PMID:16601880, PMID:27362913) (PS4). Functional studies show <10% of normal enzyme activity compared to wildtype (PMID:26179960) (PS3). Computational predictions support a deleterious effect on the gene or gene product (PP3). The variant has been reported in dbSNP (rs386833587) and in the HGMD database: CM042354. It has been reported as Pathogenic/Likely pathogenic by other diagnostic laboratories (ClinVar Variation ID: 56104). -
Pathogenic, criteria provided, single submitter	clinical testing	Women's Health and Genetics/Laboratory Corporation of America, LabCorp	Sep 28, 2018	Variant summary: GLDC c.806C>T (p.Thr269Met) results in a non-conservative amino acid change in 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 246244 control chromosomes. c.806C>T has been reported in the literature in multiple individuals affected with Glycine Encephalopathy (Non-Ketotic Hyperglycinemia) both as a compound heterozygous and homozygous allele (Conter_2006, Coughlin_2017). These data indicate that the variant is very likely to be associated with disease. At least one publication reports experimental evidence evaluating an impact on residual enzyme activity, where <10% of normal activity was observed in vitro (Swanson_2015). One clinical diagnostic laboratory has submitted clinical-significance assessments for this variant to ClinVar after 2014 without evidence for independent evaluation and classified the variant as likely pathogenic. Based on the evidence outlined above, the variant was classified as pathogenic. -

not provided Pathogenic:4

Pathogenic, no assertion criteria provided	clinical testing	Diagnostic Laboratory, Department of Genetics, University Medical Center Groningen	-	- -
Pathogenic, criteria provided, single submitter	clinical testing	GeneDx	Mar 18, 2022	Published functional studies demonstrate that this variant leads to an unstable protein and reduced enzyme activity (Swanson et al., 2015); Not observed at a 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: 15272469, 26179960, 16601880, 16450403, 27362913) -
Likely pathogenic, no assertion criteria provided	clinical testing	Genome Diagnostics Laboratory, Amsterdam University Medical Center	-	- -
Pathogenic, no assertion criteria provided	clinical testing	Genome Diagnostics Laboratory, University Medical Center Utrecht	-	- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Uncertain	0.45
BayesDel_addAF	Pathogenic	0.42	D
BayesDel_noAF	Pathogenic	0.55
Cadd	Pathogenic	30
Dann	Pathogenic	1.0
DEOGEN2	Pathogenic	0.83	D;.
Eigen	Pathogenic	0.94
Eigen_PC	Pathogenic	0.88
FATHMM_MKL	Uncertain	0.94	D
LIST_S2	Pathogenic	0.98	D;D
M_CAP	Pathogenic	0.32	D
MetaRNN	Pathogenic	0.98	D;D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	3.7	H;.
MutationTaster	Benign	1.0	D
PrimateAI	Uncertain	0.73	T
PROVEAN	Pathogenic	-5.3	D;.
REVEL	Pathogenic	0.94
Sift	Pathogenic	0.0	D;.
Sift4G	Uncertain	0.026	D;.
Polyphen		1.0	D;.
Vest4		0.91
MutPred		0.87		Loss of phosphorylation at T269 (P = 0.0335);.;
MVP		0.99
MPC		0.32
ClinPred		0.99	D
GERP RS		5.5
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.93
gMVP		0.91

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: rs386833587; hg19: chr9-6605186;