rs201623252

Positions:

Variant summary

Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PM1PM2PM5PP3_StrongPP5_Very_Strong

The NM_054012.4(ASS1):c.380G>A(p.Arg127Gln) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000062 in 1,613,924 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 Pathogenic (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R127W) has been classified as Pathogenic.

Frequency

Genomes: 𝑓 0.000013 ( 0 hom., cov: 33)

Exomes 𝑓: 0.0000055 ( 0 hom. )

Consequence

ASS1
NM_054012.4 missense

Scores

Clinical Significance

Pathogenic criteria provided, multiple submitters, no conflicts P:5

Conservation

PhyloP100: 8.34

Variant links:

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 links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Pathogenic. Variant got 18 ACMG points.

PM1

In a helix (size 11) in uniprot entity ASSY_HUMAN there are 4 pathogenic changes around while only 0 benign (100%) in NM_054012.4

PM2

Very rare variant in population databases, with high coverage;

PM5

Other missense variant is known to change same aminoacid residue: Variant chr9-130464126-C-T is described in Lovd as [Pathogenic].

PP3

MetaRNN computational evidence supports a deleterious effect, 0.99

PP5

Variant 9-130464127-G-A is Pathogenic according to our data. Variant chr9-130464127-G-A is described in ClinVar as [Pathogenic]. Clinvar id is 623334.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr9-130464127-G-A is described in Lovd as [Pathogenic]. Variant chr9-130464127-G-A is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
ASS1	NM_054012.4 linkuse as main transcript	c.380G>A	p.Arg127Gln	missense_variant	5/15	ENST00000352480.10	NP_446464.1
ASS1	NM_000050.4 linkuse as main transcript	c.380G>A	p.Arg127Gln	missense_variant	6/16		NP_000041.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
ASS1	ENST00000352480.10 linkuse as main transcript	c.380G>A	p.Arg127Gln	missense_variant	5/15	1	NM_054012.4	ENSP00000253004	P1

Frequencies

GnomAD3 genomes

AF:

0.0000132

AC:

AN:

152044

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.0000655

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.00

Gnomad OTH

AF:

0.000480

GnomAD3 exomes

AF:

0.00000398

AC:

AN:

251448

Hom.:

AF XY:

0.00000736

AC XY:

AN XY:

135900

show subpopulations

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:

0.00000879

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000547

AC:

AN:

1461880

Hom.:

Cov.:

AF XY:

0.00000688

AC XY:

AN XY:

727242

show subpopulations

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:

0.00000719

Gnomad4 OTH exome

AF:

0.00

GnomAD4 genome

AF:

0.0000132

AC:

AN:

152044

Hom.:

Cov.:

AF XY:

0.0000135

AC XY:

AN XY:

74250

show subpopulations

Gnomad4 AFR

AF:

0.00

Gnomad4 AMR

AF:

0.0000655

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.00

Gnomad4 OTH

AF:

0.000480

Bravo

AF:

0.00000756

ExAC

AF:

0.00000824

AC:

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:5

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Citrullinemia type I

Pathogenic:3

Pathogenic, criteria provided, single submitter	curation	Department Of Genetics, Sultan Qaboos University Hospital, Sultan Qaboos University	Dec 30, 2023	- -
Pathogenic, no assertion criteria provided	clinical testing	Natera, Inc.	Oct 08, 2020	- -
Pathogenic, criteria provided, single submitter	clinical testing	Baylor Genetics	Mar 30, 2024	- -

Citrullinemia

Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Sep 04, 2023

For these reasons, this variant has been classified as Pathogenic. This variant disrupts the p.Arg127 amino acid residue in ASS1. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 19006241, 23246278, 27287393). This suggests that this residue is clinically significant, and that variants that disrupt this residue are likely to be disease-causing. 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. ClinVar contains an entry for this variant (Variation ID: 623334). This missense change has been observed in individual(s) with citrulinemia (PMID: 14680976, 23099195, 28111830, 31208364). This variant is present in population databases (rs201623252, gnomAD 0.0009%). This sequence change replaces arginine, which is basic and polar, with glutamine, which is neutral and polar, at codon 127 of the ASS1 protein (p.Arg127Gln). -

not provided

Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

GeneDx

Jan 19, 2023

Published functional studies found this variant is associated with significantly reduced enzyme activity compared to wild-type (Diez-Fernandez C et al., 2016; Zielonka M et al., 2019); Identified in individuals with positive newborn screening for citrullinemia who were also heterozygous for another variant in the ASS1 gene (Haberle J et al., 2003; Woo HI et al., 2013); Not observed at significant frequency in large population cohorts (gnomAD); In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; This variant is associated with the following publications: (PMID: 29896748, 31469252, 29273096, 25443352, 36263152, 31208364, 27915290, 26659599, 28111830, 23099195, 19006241, 24508627, 27287393, 14680976) -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Pathogenic

0.99

BayesDel_addAF

Pathogenic

0.57

BayesDel_noAF

Pathogenic

0.58

CADD

Pathogenic

DANN

Pathogenic

1.0

DEOGEN2

Pathogenic

1.0

D;D;D;.

Eigen

Pathogenic

0.95

Eigen_PC

Pathogenic

0.82

FATHMM_MKL

Uncertain

0.96

LIST_S2

Uncertain

0.91

.;.;D;D

M_CAP

Pathogenic

0.56

MetaRNN

Pathogenic

0.99

D;D;D;D

MetaSVM

Pathogenic

0.98

MutationAssessor

Pathogenic

4.4

H;H;H;.

MutationTaster

Benign

1.0

D;D;D;D

PrimateAI

Uncertain

0.57

PROVEAN

Uncertain

-3.8

D;D;D;D

REVEL

Pathogenic

0.98

Sift

Uncertain

0.0010

D;D;D;T

Sift4G

Uncertain

0.019

D;D;D;D

Polyphen

1.0

D;D;D;.

Vest4

0.97

MutPred

0.98

Gain of sheet (P = 0.0827);Gain of sheet (P = 0.0827);Gain of sheet (P = 0.0827);Gain of sheet (P = 0.0827);

MVP

0.98

MPC

0.97

ClinPred

1.0

GERP RS

4.5

Varity_R

0.93

gMVP

0.93

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.030

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

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over