16-81082963-C-A

Variant summary

Our verdict is Uncertain significance. Variant got 4 ACMG points: 4P and 0B. PM2 PP3_Moderate

The NM_004483.5(GCSH):c.425G>T(p.Gly142Val) variant causes a missense, splice region change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000211 in 1,422,234 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 2/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: not found (cov: 27)
  • Exomes 𝑓: 0.0000021 (0 hom.)
• Consequence: GCSH NM_004483.5 missense, splice_region
• Scores: Splicing: ADA: 0.9998
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 7.79

Genes affected

GCSH (HGNC:4208): (glycine cleavage system protein H) 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 H protein, which transfers the methylamine group of glycine from the P protein to the T protein. Defects in this gene are a cause of nonketotic hyperglycinemia (NKH). Two transcript variants, one protein-coding and the other probably not protein-coding,have been found for this gene. Also, several transcribed and non-transcribed pseudogenes of this gene exist throughout the genome.[provided by RefSeq, Jan 2010]

ACMG classification

Verdict is Uncertain_significance. Variant got 4 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: Splicing scoreres supports a deletorius effect: Scorers claiming Pathogenic: dbscSNV1_ADA, dbscSNV1_RF. No scorers claiming Uncertain. Scorers claiming Benign: max_spliceai.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
GCSH	NM_004483.5	c.425G>T	p.Gly142Val	missense_variant, splice_region_variant	5/5	ENST00000315467.9

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
GCSH	ENST00000315467.9	c.425G>T	p.Gly142Val	missense_variant, splice_region_variant	5/5	1	NM_004483.5	P1

Frequencies

GnomAD3 genomes Cov.: 27

GnomAD3 exomes AF: 0.00000398 AC: 1 AN: 251078 Hom.: 0 AF XY: 0.00000737 AC XY: 1 AN XY: 135708

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: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00000882

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000211 AC: 3 AN: 1422234 Hom.: 0 Cov.: 25 AF XY: 0.00000141 AC XY: 1 AN XY: 710140

Gnomad4 AFR exome AF: 0.0000306

Gnomad4 AMR exome AF: 0.0000224

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 9.29e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 27

ExAC AF: 0.00000824 AC: 1

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

3billion

Sep 01, 2022

The variant is observed at an extremely low frequency in the gnomAD v2.1.1 dataset (total allele frequency: <0.001%). In silico tool predictions suggest damaging effect of the variant on gene or gene product (REVEL: 0.83; 3Cnet: 0.94). Therefore, this variant is classified as uncertain significance according to the recommendation of ACMG/AMP guideline. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.99
BayesDel_addAF	Pathogenic	0.38	D
BayesDel_noAF	Pathogenic	0.31
Cadd	Pathogenic	28
Dann	Uncertain	1.0
DEOGEN2	Uncertain	0.57	D;.
Eigen	Pathogenic	0.98
Eigen_PC	Pathogenic	0.90
FATHMM_MKL	Pathogenic	1.0	D
LIST_S2	Uncertain	0.91	D;D
M_CAP	Uncertain	0.11	D
MetaRNN	Pathogenic	0.98	D;D
MetaSVM	Uncertain	0.58	D
MutationAssessor	Pathogenic	3.8	H;.
MutationTaster	Benign	1.0	D
PrimateAI	Uncertain	0.54	T
PROVEAN	Pathogenic	-8.5	D;.
REVEL	Pathogenic	0.83
Sift	Uncertain	0.016	D;.
Sift4G	Uncertain	0.030	D;.
Polyphen		1.0	D;.
Vest4		0.95
MutPred		0.94		Gain of catalytic residue at G142 (P = 0.0738);.;
MVP		0.95
MPC		1.3
ClinPred		1.0	D
GERP RS		5.3
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.96
gMVP		0.80

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	1.0
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: rs746937065; hg19: chr16-81116568;