rs1554641505

Positions:

• chr9-6533097-C-A
• chr9-6533097-C-T

Variant summary

Our verdict is Likely pathogenic. Variant got 8 ACMG points: 8P and 0B. PM2 PM5 PP3_Strong

The NM_000170.3(GLDC):​c.2983G>T​(p.Asp995Tyr) 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. D995N) has been classified as Pathogenic.

• Frequency: Genomes: not found (cov: 32)
• Consequence: GLDC NM_000170.3 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 7.86

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 Likely_pathogenic. Variant got 8 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr9-6533097-C-T is described in Lovd as [Pathogenic].
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.989

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
GLDC	NM_000170.3	c.2983G>T	p.Asp995Tyr	missense_variant	25/25	ENST00000321612.8	NP_000161.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
GLDC	ENST00000321612.8	c.2983G>T	p.Asp995Tyr	missense_variant	25/25	1	NM_000170.3	ENSP00000370737	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 30

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Non-ketotic hyperglycinemia Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Nov 13, 2018

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 are either unavailable or do not agree on the potential impact of this missense change (SIFT: "Deleterious"; PolyPhen-2: "Probably Damaging"; Align-GVGD: "Class C15"). 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 aspartic acid with tyrosine at codon 995 of the GLDC protein (p.Asp995Tyr). The aspartic acid residue is highly conserved and there is a large physicochemical difference between aspartic acid and tyrosine. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.99
BayesDel_addAF	Pathogenic	0.48	D
BayesDel_noAF	Pathogenic	0.46
CADD	Pathogenic	31
DANN	Uncertain	0.99
DEOGEN2	Pathogenic	0.82	D;.;.;.
Eigen	Pathogenic	0.90
Eigen_PC	Pathogenic	0.78
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Pathogenic	0.99	D;D;D;D
M_CAP	Pathogenic	0.39	D
MetaRNN	Pathogenic	0.99	D;D;D;D
MetaSVM	Pathogenic	1.0	D
MutationAssessor	Pathogenic	4.1	H;.;.;.
MutationTaster	Benign	1.0	D
PrimateAI	Uncertain	0.76	T
PROVEAN	Pathogenic	-8.0	D;.;.;.
REVEL	Pathogenic	0.95
Sift	Pathogenic	0.0	D;.;.;.
Sift4G	Pathogenic	0.0	D;.;.;.
Polyphen		1.0	D;.;.;.
Vest4		0.96
MutPred		0.88		Gain of phosphorylation at D995 (P = 0.0564);.;.;.;
MVP		0.99
MPC		0.34
ClinPred		1.0	D
GERP RS		5.1
Varity_R		0.96
gMVP		0.99

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: rs1554641505; hg19: chr9-6533097;