Genetic Variant NM_000170.3:c.2481_2484delACAA (chr9-6550887-CTTGT-C) – ACMG Classification: Pathogenic (18 pts)

Variant summary

Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PVS1PM2PP5_Very_Strong

The NM_000170.3(GLDC):c.2481_2484delACAA(p.Gln828ProfsTer7) variant causes a frameshift change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Likely pathogenic (★★). Variant results in nonsense mediated mRNA decay.

Frequency

Genomes: not found (cov: 32)

Exomes 𝑓: 0.0000068 ( 0 hom. )

Failed GnomAD Quality Control

Consequence

GLDC
NM_000170.3 frameshift

Scores

Not classified

Clinical Significance

Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:5

Conservation

PhyloP100: 7.44

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 links:

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ACMG classification

Classification made for transcript

Verdict is Pathogenic. Variant got 18 ACMG points.

PVS1

Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.

PM2

Very rare variant in population databases, with high coverage;

PP5

Variant 9-6550887-CTTGT-C is Pathogenic according to our data. Variant chr9-6550887-CTTGT-C is described in ClinVar as [Likely_pathogenic]. Clinvar id is 557789.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr9-6550887-CTTGT-C is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
GLDC	NM_000170.3 link	c.2481_2484delACAA	p.Gln828ProfsTer7	frameshift_variant	Exon 21 of 25	ENST00000321612.8	NP_000161.2	P23378

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
GLDC	ENST00000321612.8 link	c.2481_2484delACAA	p.Gln828ProfsTer7	frameshift_variant	Exon 21 of 25	1	NM_000170.3	ENSP00000370737.4		P23378

Frequencies

GnomAD3 genomes

Cov.:

GnomAD3 exomes

AF:

0.0000119

AC:

AN:

251484

Hom.:

AF XY:

0.00000736

AC XY:

AN XY:

135912

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.0000544

Gnomad SAS exome

AF:

0.0000327

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00000879

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

Data not reliable, filtered out with message: AS_VQSR

AF:

0.00000685

AC:

AN:

1460620

Hom.:

AF XY:

0.00000688

AC XY:

AN XY:

726744

show subpopulations

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:

0.0000116

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.00000540

Gnomad4 OTH exome

AF:

0.0000497

GnomAD4 genome

Cov.:

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:5

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Glycine encephalopathy

Pathogenic:4

Nov 16, 2021

Fulgent Genetics, Fulgent Genetics

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

May 11, 2021

Natera, Inc.

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

Apr 10, 2018

Counsyl

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Jan 25, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change creates a premature translational stop signal (p.Gln828Profs*7) in the GLDC gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in GLDC are known to be pathogenic (PMID: 16601880). This variant is present in population databases (rs766762760, gnomAD 0.006%). This premature translational stop signal has been observed in individual(s) with nonketotic hyperglycinemia (PMID: 26179960). ClinVar contains an entry for this variant (Variation ID: 557789). For these reasons, this variant has been classified as Pathogenic. -

not provided

Pathogenic:1

May 22, 2023

GeneDx

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Frameshift variant predicted to result in protein truncation or nonsense mediated decay in a gene for which loss-of-function is a known mechanism of disease; Not observed at significant frequency in large population cohorts (gnomAD); This variant is associated with the following publications: (PMID: 26179960) -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

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

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over