NM_000170.3:c.2216G>A

Variant names:

• chr9-6554768-C-T
• rs121964980
• NM_000170.3:c.2216G>A

Variant summary

Our verdict is Pathogenic. The variant received 16 ACMG points: 16P and 0B. PM1 PM2 PM5 PP3_Moderate PP5_Very_Strong

The NM_000170.3(GLDC):​c.2216G>A​(p.Arg739His) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000292 in 1,612,332 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 13/22 in silico tools predict a damaging 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. R739L) has been classified as Uncertain significance.

• Frequency:
  • Genomes: 𝑓 0.000059 (0 hom., cov: 33)
  • Exomes 𝑓: 0.000026 (0 hom.)
• Consequence: GLDC NM_000170.3 missense
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:9
• Conservation: PhyloP100: 7.53
• Publications: 12 publications found

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

ACMG classification

Our verdict: Pathogenic. The variant received 16 ACMG points.

• PM1: In a hotspot region, there are 7 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 1 benign, 14 uncertain in NM_000170.3
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr9-6554769-G-A is described in ClinVar as Likely_pathogenic. ClinVar VariationId is 1490298.Status of the report is criteria_provided_single_submitter, 1 stars.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.908
• PP5: Variant 9-6554768-C-T is Pathogenic according to our data. Variant chr9-6554768-C-T is described in ClinVar as Pathogenic/Likely_pathogenic. ClinVar VariationId is 11990.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
GLDC	NM_000170.3	c.2216G>A	p.Arg739His	missense_variant	Exon 19 of 25	ENST00000321612.8	NP_000161.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
GLDC	ENST00000321612.8	c.2216G>A	p.Arg739His	missense_variant	Exon 19 of 25	1	NM_000170.3	ENSP00000370737.4

Frequencies

GnomAD3 genomes AF: 0.0000591 AC: 9 AN: 152204 Hom.: 0 Cov.: 33

Gnomad AFR AF: 0.0000724

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: 0.0000882

Gnomad OTH AF: 0.00

GnomAD2 exomes AF: 0.0000363 AC: 9 AN: 247686 AF XY: 0.0000374

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.0000583

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.0000547

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.0000535

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.0000260 AC: 38 AN: 1460010 Hom.: 0 Cov.: 31 AF XY: 0.0000207 AC XY: 15 AN XY: 726104

African (AFR) AF: 0.0000299 AC: 1 AN: 33446

American (AMR) AF: 0.0000449 AC: 2 AN: 44562

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26080

East Asian (EAS) AF: 0.0000252 AC: 1 AN: 39688

South Asian (SAS) AF: 0.00 AC: 0 AN: 85660

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53340

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5718

European-Non Finnish (NFE) AF: 0.0000297 AC: 33 AN: 1111168

Other (OTH) AF: 0.0000166 AC: 1 AN: 60348

GnomAD4 genome AF: 0.0000591 AC: 9 AN: 152322 Hom.: 0 Cov.: 33 AF XY: 0.0000671 AC XY: 5 AN XY: 74490

African (AFR) AF: 0.0000722 AC: 3 AN: 41568

American (AMR) AF: 0.00 AC: 0 AN: 15308

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3472

East Asian (EAS) AF: 0.00 AC: 0 AN: 5180

South Asian (SAS) AF: 0.00 AC: 0 AN: 4828

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10622

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 294

European-Non Finnish (NFE) AF: 0.0000882 AC: 6 AN: 68028

Other (OTH) AF: 0.00 AC: 0 AN: 2110

Alfa AF: 0.0000586 Hom.: 0

Bravo AF: 0.0000567

ESP6500AA AF: 0.00 AC: 0

ESP6500EA AF: 0.000233 AC: 2

ExAC AF: 0.0000247 AC: 3

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:9

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Glycine encephalopathy Pathogenic:5

Nov 11, 2021

Myriad Genetics, Inc.

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

NM_000170.2(GLDC):c.2216G>A(R739H) is a missense variant classified as likely pathogenic in the context of glycine encephalopathy, GLDC-related. Please note that R739H may be associated with an attenuated form of glycine encephalopathy, GLDC-related. R739H has been observed in cases with relevant disease (PMID: 15824356, 16450403, 17074608, 27362913, 33977025, SSIEM_2005_(no PMID; abstract)). Functional assessments of this variant are available in the literature (PMID: 15824356). R739H has been observed in population frequency databases (gnomAD: NFE 0.01%). In summary, NM_000170.2(GLDC):c.2216G>A(R739H) is a missense variant that has functional support for pathogenicity and has been observed more frequently in cases with the relevant disease than in healthy populations. Please note: this variant was assessed in the context of healthy population screening. -

Sep 16, 2020

Natera, Inc.

Significance: Likely pathogenic

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

Nov 21, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces arginine, which is basic and polar, with histidine, which is basic and polar, at codon 739 of the GLDC protein (p.Arg739His). This variant is present in population databases (rs121964980, gnomAD 0.007%). This missense change has been observed in individual(s) with GLDC-related conditions (PMID: 15824356, 16450403, 17074608; internal data). ClinVar contains an entry for this variant (Variation ID: 11990). Invitae Evidence Modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) indicates that this missense variant is expected to disrupt GLDC protein function with a positive predictive value of 95%. Experimental studies have shown that this missense change affects GLDC function (PMID: 15824356). For these reasons, this variant has been classified as Pathogenic. -

Jul 03, 2020

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

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Variant summary: GLDC c.2216G>A (p.Arg739His) 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 3.6e-05 in 247686 control chromosomes. c.2216G>A has been reported in the literature in individuals affected with Glycine Encephalopathy (Non-Ketotic Hyperglycinemia) (example, Dinopoulos_2005, Kure_2006, unpublished source from bioRxiv_2019). These data indicate that the variant is likely to be associated with disease. At least one publication reports experimental evidence evaluating an impact on protein function (Dinopoulos_2005). The most pronounced variant effect results in <10% of normal GLDC enzyme activity. 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. -

-

Baylor Genetics

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

not provided Pathogenic:2

Jan 26, 2024

GeneDx

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Published functional studies demonstrate that the R739H variant had decreased enzymatic activity (PMID: 15824356); In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; Not observed at significant frequency in large population cohorts (gnomAD); This variant is associated with the following publications: (PMID: 15824356, 16450403, 31589614, 30833958, Roa2023[Abstract], 33977025, 17074608) -

Apr 01, 2024

CeGaT Center for Human Genetics Tuebingen

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

GLDC: PM1, PM2, PM3, PP3, PS3:Supporting -

Glycine encephalopathy 1 Pathogenic:2

Feb 08, 2024

Fulgent Genetics, Fulgent Genetics

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Apr 12, 2005

OMIM

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: literature only

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Uncertain	0.45
BayesDel_addAF	Pathogenic	0.43	D
BayesDel_noAF	Pathogenic	0.55
CADD	Pathogenic	33
DANN	Pathogenic	1.0
DEOGEN2	Uncertain	0.77	D;.;.
Eigen	Pathogenic	0.95
Eigen_PC	Pathogenic	0.87
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Pathogenic	1.0	D;D;D
M_CAP	Pathogenic	0.48	D
MetaRNN	Pathogenic	0.91	D;D;D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	4.1	H;.;.
PhyloP100		7.5
PrimateAI	Pathogenic	0.82	D
PROVEAN	Pathogenic	-4.5	D;.;.
REVEL	Pathogenic	0.94
Sift	Uncertain	0.0080	D;.;.
Sift4G	Uncertain	0.0090	D;.;.
Polyphen		1.0	D;.;.
Vest4		0.97
MVP		1.0
MPC		0.34
ClinPred		0.99	D
GERP RS		5.4
PromoterAI		0.0041	Neutral
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.71
gMVP		0.91
Mutation Taster		=9/91	disease causing (ClinVar)

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.090		Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Other links and lift over

dbSNP: rs121964980; hg19: chr9-6554768; COSMIC: COSV58676016; COSMIC: COSV58676016;