chr9-130494921-A-G

Position:

• chr9-130494921-A-G

Variant summary

Our verdict is Likely pathogenic. Variant got 6 ACMG points: 6P and 0B. PM2 PP3_Strong

The NM_054012.4(ASS1):​c.1025A>G​(p.Gln342Arg) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,288 control chromosomes in the GnomAD database, with no homozygous occurrence. 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. Q342P) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: ASS1 NM_054012.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 8.66

Genes affected

ASS1 (HGNC:758): (argininosuccinate synthase 1) The protein encoded by this gene catalyzes the penultimate step of the arginine biosynthetic pathway. There are approximately 10 to 14 copies of this gene including the pseudogenes scattered across the human genome, among which the one located on chromosome 9 appears to be the only functional gene for argininosuccinate synthetase. Mutations in the chromosome 9 copy of this gene cause citrullinemia. Two transcript variants encoding the same protein have been found for this gene. [provided by RefSeq, Aug 2012]

ACMG classification

Verdict is Likely_pathogenic. Variant got 6 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.982

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
ASS1	NM_054012.4	c.1025A>G	p.Gln342Arg	missense_variant	13/15	ENST00000352480.10
ASS1	NM_000050.4	c.1025A>G	p.Gln342Arg	missense_variant	14/16

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
ASS1	ENST00000352480.10	c.1025A>G	p.Gln342Arg	missense_variant	13/15	1	NM_054012.4	P1
ASS1	ENST00000372393.7	c.1025A>G	p.Gln342Arg	missense_variant	14/16	5		P1
ASS1	ENST00000372394.5	c.1025A>G	p.Gln342Arg	missense_variant	14/16	2		P1
ASS1	ENST00000372386.6	n.296A>G		non_coding_transcript_exon_variant	4/6	3

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461288 Hom.: 0 Cov.: 31 AF XY: 0.00 AC XY: 0 AN XY: 726980

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: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 8.99e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Citrullinemia Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Sep 01, 2021

This sequence change replaces glutamine with arginine at codon 342 of the ASS1 protein (p.Gln342Arg). The glutamine residue is moderately conserved and there is a small physicochemical difference between glutamine and arginine. This variant is not present in population databases (ExAC no frequency). This variant has not been reported in the literature in individuals affected with ASS1-related conditions. 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 C0"). 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. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.92
BayesDel_addAF	Pathogenic	0.57	D
BayesDel_noAF	Pathogenic	0.57
CADD	Pathogenic	29
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	1.0	D;D;D
Eigen	Pathogenic	0.91
Eigen_PC	Pathogenic	0.80
FATHMM_MKL	Uncertain	0.95	D
LIST_S2	Pathogenic	0.99	.;.;D
M_CAP	Pathogenic	0.78	D
MetaRNN	Pathogenic	0.98	D;D;D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	3.5	M;M;M
MutationTaster	Benign	1.0	D;D;D;D
PrimateAI	Uncertain	0.65	T
PROVEAN	Uncertain	-3.8	D;D;D
REVEL	Pathogenic	0.98
Sift	Pathogenic	0.0	D;D;D
Sift4G	Pathogenic	0.0010	D;D;D
Polyphen		1.0	D;D;D
Vest4		0.91
MutPred		0.81		Gain of MoRF binding (P = 0.0338);Gain of MoRF binding (P = 0.0338);Gain of MoRF binding (P = 0.0338);
MVP		0.98
MPC		0.96
ClinPred		0.99	D
GERP RS		4.8
Varity_R		0.98
gMVP		0.95

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: rs1554725061; hg19: chr9-133370308;