chr7-30621454-G-A

Position:

• chr7-30621454-G-A

Variant summary

Our verdict is Uncertain significance. Variant got 4 ACMG points: 6P and 2B. PM1 PM2 PM5 BP4_Moderate

The NM_002047.4(GARS1):​c.1421G>A​(p.Arg474Gln) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000205 in 1,461,876 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 14/20 in silico tools predict a benign 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. R474P) has been classified as Likely pathogenic.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000021 (0 hom.)
• Consequence: GARS1 NM_002047.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 3.36

Genes affected

GARS1 (HGNC:4162): (glycyl-tRNA synthetase 1) This gene encodes glycyl-tRNA synthetase, one of the aminoacyl-tRNA synthetases that charge tRNAs with their cognate amino acids. The encoded enzyme is an (alpha)2 dimer which belongs to the class II family of tRNA synthetases. It has been shown to be a target of autoantibodies in the human autoimmune diseases, polymyositis or dermatomyositis. Two transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Oct 2015]

ACMG classification

Verdict is Uncertain_significance. Variant got 4 ACMG points.

• PM1: In a helix (size 9) in uniprot entity GARS_HUMAN there are 4 pathogenic changes around while only 0 benign (100%) in NM_002047.4
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr7-30621454-G-C is described in Lovd as [Likely_pathogenic].
• BP4: Computational evidence support a benign effect (MetaRNN=0.114702195).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
GARS1	NM_002047.4	c.1421G>A	p.Arg474Gln	missense_variant	11/17	ENST00000389266.8
GARS1	NM_001316772.1	c.1259G>A	p.Arg420Gln	missense_variant	11/17

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
GARS1	ENST00000389266.8	c.1421G>A	p.Arg474Gln	missense_variant	11/17	1	NM_002047.4	P2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD3 exomes AF: 0.00000401 AC: 1 AN: 249576 Hom.: 0 AF XY: 0.00000739 AC XY: 1 AN XY: 135406

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: 0.00000883

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000205 AC: 3 AN: 1461876 Hom.: 0 Cov.: 31 AF XY: 0.00000413 AC XY: 3 AN XY: 727242

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: 0.00000180

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

Bravo AF: 0.00000756

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Charcot-Marie-Tooth disease type 2 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Jul 19, 2017

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 output the following: SIFT: "Tolerated"; PolyPhen-2: "Benign"; Align-GVGD: "Class C0". The glutamine amino acid residue is found in multiple mammalian species, suggesting that this missense change does not adversely affect protein function. These predictions have not been confirmed by published functional studies and their clinical significance is uncertain. This variant has not been reported in the literature in individuals with GARS-related disease. This variant is not present in population databases (ExAC no frequency). This sequence change replaces arginine with glutamine at codon 474 of the GARS protein (p.Arg474Gln). The arginine residue is moderately conserved and there is a small physicochemical difference between arginine and glutamine. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.11
BayesDel_addAF	Benign	-0.070	T
BayesDel_noAF	Benign	-0.34
CADD	Benign	20
DANN	Uncertain	0.98
DEOGEN2	Benign	0.075	T
Eigen	Benign	-0.48
Eigen_PC	Benign	-0.32
FATHMM_MKL	Uncertain	0.82	D
LIST_S2	Uncertain	0.92	D
M_CAP	Benign	0.033	D
MetaRNN	Benign	0.11	T
MetaSVM	Benign	-0.55	T
MutationTaster	Benign	0.84	D
PrimateAI	Benign	0.44	T
PROVEAN	Benign	-0.32	N
REVEL	Benign	0.20
Sift	Benign	0.32	T
Sift4G	Benign	0.21	T
Polyphen		0.0050	B
Vest4		0.18
MutPred		0.35		Gain of ubiquitination at K477 (P = 0.0357);
MVP		0.37
MPC		0.40
ClinPred		0.25	T
GERP RS		2.4
Varity_R		0.070
gMVP		0.40

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.020		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: rs1345590827; hg19: chr7-30661070;