rs1554982237

Positions:

• chr9-130454318-AG-A

Variant summary

Our verdict is Pathogenic. Variant got 12 ACMG points: 12P and 0B. PVS1 PM2 PP5_Moderate

The NM_054012.4(ASS1):​c.120del​(p.Lys41ArgfsTer12) variant causes a frameshift change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Pathogenic (★). Variant results in nonsense mediated mRNA decay.

• Frequency: Genomes: not found (cov: 33)
• Consequence: ASS1 NM_054012.4 frameshift
• Clinical Significance: Pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 2.33

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 12 ACMG points.

• PVS1: Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 9-130454318-AG-A is Pathogenic according to our data. Variant chr9-130454318-AG-A is described in ClinVar as [Pathogenic]. Clinvar id is 528374.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
ASS1	NM_054012.4	c.120del	p.Lys41ArgfsTer12	frameshift_variant	3/15	ENST00000352480.10	NP_446464.1
ASS1	NM_000050.4	c.120del	p.Lys41ArgfsTer12	frameshift_variant	4/16		NP_000041.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
ASS1	ENST00000352480.10	c.120del	p.Lys41ArgfsTer12	frameshift_variant	3/15	1	NM_054012.4	ENSP00000253004	P1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 33

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

Submissions by phenotype

Citrullinemia Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Mar 12, 2020

For these reasons, this variant has been classified as Pathogenic. Loss-of-function variants in ASS1 are known to be pathogenic (PMID: 18473344, 19006241). This variant has not been reported in the literature in individuals with ASS1-related disease. This variant is not present in population databases (ExAC no frequency). This sequence change creates a premature translational stop signal (p.Lys41Argfs*12) in the ASS1 gene. It is expected to result in an absent or disrupted protein product. -

Computational scores

Source: dbNSFP v4.3

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

LitVar

Other links and lift over

dbSNP: rs1554982237; hg19: chr9-133329705;