NM_054012.4:c.8G>A

Variant names:

• chr9-130452236-G-A
• rs1845344324
• NM_054012.4:c.8G>A

Variant summary

Our verdict is Uncertain significance. The variant received 3 ACMG points: 3P and 0B. PM2 PP2

The NM_054012.4(ASS1):​c.8G>A​(p.Ser3Asn) variant causes a missense change. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: ASS1 NM_054012.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 6.55
• Publications: 0 publications found

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]

ASS1 Gene-Disease associations (from GenCC):

• citrullinemia type I

  Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), ClinGen, Myriad Women’s Health, G2P
• acute neonatal citrullinemia type I

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
• adult-onset citrullinemia type I

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Uncertain_significance. The variant received 3 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant in the gene, where a lot of missense mutations are associated with disease in ClinVar. The gene has 49 curated pathogenic missense variants (we use a threshold of 10). The gene has 4 curated benign missense variants. Gene score misZ: 0.75759 (below the threshold of 3.09). Trascript score misZ: 1.8061 (below the threshold of 3.09). GenCC associations: The gene is linked to citrullinemia type I, adult-onset citrullinemia type I, acute neonatal citrullinemia type I.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
ASS1	NM_054012.4	c.8G>A	p.Ser3Asn	missense_variant	Exon 2 of 15	ENST00000352480.10	NP_446464.1
ASS1	NM_000050.4	c.8G>A	p.Ser3Asn	missense_variant	Exon 3 of 16		NP_000041.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
ASS1	ENST00000352480.10	c.8G>A	p.Ser3Asn	missense_variant	Exon 2 of 15	1	NM_054012.4	ENSP00000253004.6

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Citrullinemia Uncertain:1

Aug 24, 2021

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces serine with asparagine at codon 3 of the ASS1 protein (p.Ser3Asn). The serine residue is moderately conserved and there is a small physicochemical difference between serine and asparagine. 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 (SIFT, PolyPhen-2, Align-GVGD) all suggest that this variant is likely to be tolerated. 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	Benign	0.10
BayesDel_addAF	Uncertain	0.13	D
BayesDel_noAF	Uncertain	-0.060
CADD	Pathogenic	26
DANN	Uncertain	0.99
DEOGEN2	Benign	0.40	T;T;T;.;.
Eigen	Benign	0.042
Eigen_PC	Benign	0.20
FATHMM_MKL	Uncertain	0.84	D
LIST_S2	Benign	0.81	.;.;T;T;T
M_CAP	Uncertain	0.13	D
MetaRNN	Benign	0.33	T;T;T;T;T
MetaSVM	Uncertain	0.75	D
MutationAssessor	Benign	0.97	L;L;L;.;.
PhyloP100		6.5
PrimateAI	Uncertain	0.52	T
PROVEAN	Benign	-1.2	N;N;N;N;N
REVEL	Uncertain	0.31
Sift	Benign	0.052	T;T;T;T;T
Sift4G	Benign	0.10	T;T;T;T;T
Polyphen		0.19	B;B;B;.;.
Vest4		0.34
MutPred		0.21		Loss of glycosylation at S3 (P = 0.0589);Loss of glycosylation at S3 (P = 0.0589);Loss of glycosylation at S3 (P = 0.0589);Loss of glycosylation at S3 (P = 0.0589);Loss of glycosylation at S3 (P = 0.0589);
MVP		0.97
MPC		0.35
ClinPred		0.81	D
GERP RS		5.0
PromoterAI		0.036	Neutral
Varity_R		0.14
gMVP		0.46
Mutation Taster		=89/11	polymorphism

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.26		Details are displayed if max score is > 0.2
DS_AG_spliceai		0.26		Position offset: 28

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

Other links and lift over

dbSNP: rs1845344324; hg19: chr9-133327623;