chr9-130471489-G-C

Variant names:

• chr9-130471489-G-C
• NM_054012.4:c.571G>C

Variant summary

Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PS1_Moderate PM2 PM5 PP3_Strong PP5_Very_Strong

The NM_054012.4(ASS1):​c.571G>C​(p.Glu191Gln) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000137 in 1,461,824 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 Likely pathogenic (★★). Another nucleotide change resulting in the same amino acid substitution has been previously reported as Likely pathogenic in UniProt. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. E191K) has been classified as Pathogenic.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: ASS1 NM_054012.4 missense
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:2
• Conservation: PhyloP100: 7.33

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 Pathogenic. Variant got 18 ACMG points.

• PS1: Transcript NM_054012.4 (ASS1) is affected with MISSENSE_VARIANT having same AA change as one Pathogenic present in UniProt
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr9-130471489-G-A is described in Lovd as [Pathogenic].
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.986
• PP5: Variant 9-130471489-G-C is Pathogenic according to our data. Variant chr9-130471489-G-C is described in ClinVar as [Likely_pathogenic]. Clinvar id is 2678946.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr9-130471489-G-C is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
ASS1	NM_054012.4	c.571G>C	p.Glu191Gln	missense_variant	Exon 8 of 15	ENST00000352480.10	NP_446464.1
ASS1	NM_000050.4	c.571G>C	p.Glu191Gln	missense_variant	Exon 9 of 16		NP_000041.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
ASS1	ENST00000352480.10	c.571G>C	p.Glu191Gln	missense_variant	Exon 8 of 15	1	NM_054012.4	ENSP00000253004.6

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1461824 Hom.: 0 Cov.: 31 AF XY: 0.00 AC XY: 0 AN XY: 727216

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: 0.00000180

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Citrullinemia Pathogenic:1

Mar 12, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces glutamic acid, which is acidic and polar, with glutamine, which is neutral and polar, at codon 191 of the ASS1 protein (p.Glu191Gln). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individual(s) with citrullinemia type I and/or elevated citrulline (PMID: 27287393; Invitae). In at least one individual the data is consistent with being in trans (on the opposite chromosome) from a pathogenic variant. Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is expected to disrupt ASS1 protein function with a positive predictive value of 80%. Experimental studies have shown that this missense change affects ASS1 function (PMID: 27287393). This variant disrupts the p.Glu191 amino acid residue in ASS1. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 12815590, 24713661, 28111830; Invitae). This suggests that this residue is clinically significant, and that variants that disrupt this residue are likely to be disease-causing. For these reasons, this variant has been classified as Pathogenic. -

Citrullinemia type I Pathogenic:1

Oct 25, 2023

Baylor Genetics

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.99
BayesDel_addAF	Pathogenic	0.53	D
BayesDel_noAF	Pathogenic	0.53
CADD	Pathogenic	27
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	1.0	D;D;D;.;.
Eigen	Pathogenic	0.89
Eigen_PC	Pathogenic	0.85
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Uncertain	0.88	.;.;D;D;D
M_CAP	Pathogenic	0.33	D
MetaRNN	Pathogenic	0.99	D;D;D;D;D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	4.3	H;H;H;.;.
PrimateAI	Pathogenic	0.80	T
PROVEAN	Uncertain	-2.8	D;D;D;D;D
REVEL	Pathogenic	0.96
Sift	Uncertain	0.020	D;D;D;D;D
Sift4G	Uncertain	0.042	D;D;D;D;D
Polyphen		0.87	P;P;P;.;.
Vest4		0.93
MutPred		0.97		Loss of sheet (P = 0.0817);Loss of sheet (P = 0.0817);Loss of sheet (P = 0.0817);Loss of sheet (P = 0.0817);.;
MVP		0.98
MPC		0.59
ClinPred		1.0	D
GERP RS		5.7
Varity_R		0.89
gMVP		0.92

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.010		Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

No publications associated with this variant yet.

Other links and lift over

hg19: chr9-133346876;