rs777828000

Positions:

Variant summary

Our verdict is Pathogenic. Variant got 16 ACMG points: 16P and 0B. PM2PM5PP3_StrongPP5_Very_Strong

The NM_054012.4(ASS1):c.571G>A(p.Glu191Lys) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000136 in 1,614,014 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 variant affecting the same amino acid position, but resulting in a different missense (i.e. E191Q) has been classified as Likely pathogenic.

Frequency

Genomes: 𝑓 0.000026 ( 0 hom., cov: 33)

Exomes 𝑓: 0.000012 ( 0 hom. )

Consequence

ASS1
NM_054012.4 missense

Scores

Clinical Significance

Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:7

Conservation

PhyloP100: 7.33

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 16 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

PM5

Other missense variant is known to change same aminoacid residue: Variant chrnull-null-null-null is described in UniProt as null.

PP3

MetaRNN computational evidence supports a deleterious effect, 0.987

PP5

Variant 9-130471489-G-A is Pathogenic according to our data. Variant chr9-130471489-G-A is described in ClinVar as [Likely_pathogenic]. Clinvar id is 208153.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr9-130471489-G-A is described in Lovd as [Pathogenic]. Variant chr9-130471489-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.571G>A	p.Glu191Lys	missense_variant	8/15	ENST00000352480.10	NP_446464.1
ASS1	NM_000050.4 linkuse as main transcript	c.571G>A	p.Glu191Lys	missense_variant	9/16		NP_000041.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
ASS1	ENST00000352480.10 linkuse as main transcript	c.571G>A	p.Glu191Lys	missense_variant	8/15	1	NM_054012.4	ENSP00000253004	P1

Frequencies

GnomAD3 genomes

AF:

0.0000263

AC:

AN:

152190

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000965

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

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:

0.00

GnomAD3 exomes

AF:

0.0000199

AC:

AN:

251436

Hom.:

AF XY:

0.00000736

AC XY:

AN XY:

135910

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.0000289

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad SAS exome

AF:

0.0000327

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000264

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000123

AC:

AN:

1461824

Hom.:

Cov.:

AF XY:

0.0000110

AC XY:

AN XY:

727216

show subpopulations

Gnomad4 AFR exome

AF:

0.000119

Gnomad4 AMR exome

AF:

0.00

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.0000252

Gnomad4 SAS exome

AF:

0.0000116

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.00000809

Gnomad4 OTH exome

AF:

0.0000497

GnomAD4 genome

AF:

0.0000263

AC:

AN:

152190

Hom.:

Cov.:

AF XY:

0.0000135

AC XY:

AN XY:

74344

show subpopulations

Gnomad4 AFR

AF:

0.0000965

Gnomad4 AMR

AF:

0.00

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:

0.00

Alfa

AF:

0.0000279

Hom.:

Bravo

AF:

0.0000113

ExAC

AF:

0.0000247

AC:

EpiCase

AF:

0.0000545

EpiControl

AF:

0.00

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:7

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Citrullinemia type I

Pathogenic:5

Likely pathogenic, criteria provided, single submitter	clinical testing	Counsyl	Jan 03, 2018	- -
Pathogenic, no assertion criteria provided	clinical testing	Quest Diagnostics Nichols Institute San Juan Capistrano	May 25, 2014	Homozygous missense mutation in the ASS1 gene. -
Likely pathogenic, criteria provided, single submitter	clinical testing	Molecular Genetics, Royal Melbourne Hospital	Apr 11, 2023	This sequence change in ASS1 is predicted to replace glutamic acid with lysine at codon 191, p.(Glu191Lys). The glutamic acid residue is highly conserved (84/84 vertebrates, UCSC), and is located in the citrulline/aspartate binding domain (PMID: 12815590). There is a small physicochemical difference between glutamic acid and lysine. The highest population minor allele frequency in the population database gnomAD v2.1 is 0.01% (3/24,962 alleles) in the African/African American population, which is consistent with a recessive disease. This variant has been detected in at least ten individuals with citrullinaemia. Of those individuals, seven individuals were homozygous and three were compound heterozygous for the variant and a pathogenic or likely pathogenic variant (PMID: 12815590, 24713661, 28111830, 33190319, 36685561). At least one of these patients displayed a marked elevation in plasma citrulline concentrations, which is highly specific for ASS1 deficiency (PMID: 20301396, 20301631). Computational evidence predicts a deleterious effect for the missense substitution (REVEL = 0.973). Based on the classification scheme RMH Modified ACMG/AMP Guidelines v1.6.1, this variant is classified as LIKELY PATHOGENIC. Following criteria are met: PM3_Strong, PP3_Moderate, PM2_Supporting, PP4. -
Pathogenic, no assertion criteria provided	clinical testing	Natera, Inc.	Sep 16, 2020	- -
Pathogenic, criteria provided, single submitter	clinical testing	Baylor Genetics	Mar 25, 2024	- -

Citrullinemia

Pathogenic:2

Pathogenic, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Oct 25, 2023	This sequence change replaces glutamic acid, which is acidic and polar, with lysine, which is basic and polar, at codon 191 of the ASS1 protein (p.Glu191Lys). This variant is present in population databases (rs777828000, gnomAD 0.01%). This missense change has been observed in individual(s) with citrullinemia (PMID: 12815590, 24713661, 28111830; Invitae). ClinVar contains an entry for this variant (Variation ID: 208153). 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%. For these reasons, this variant has been classified as Pathogenic. -
Pathogenic, criteria provided, single submitter	clinical testing	Women's Health and Genetics/Laboratory Corporation of America, LabCorp	Jan 12, 2024	Variant summary: ASS1 c.571G>A (p.Glu191Lys) results in a conservative amino acid change located in the Arginosuccinate synthase C-terminal domain (IPR048268) of the encoded protein sequence. Four of five in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 2e-05 in 251436 control chromosomes (gnomAD). c.571G>A has been reported in the literature in multiple individuals affected with Citrullinemia Type I (Gao_2003, Sahoo_2015, Diez-Fernandez_2017). These data indicate that the variant is very likely to be associated with disease. At least one publication reports experimental evidence evaluating an impact on protein function and this variant showed less than 10% of WT activity in transfected cells (Zielonka_2019). The following publications have been ascertained in the context of this evaluation (PMID: 28111830, 12815590, 24713661, 31469252). ClinVar contains an entry for this variant (Variation ID: 208153). Based on the evidence outlined above, the variant was classified as pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Pathogenic

0.99

BayesDel_addAF

Pathogenic

0.50

BayesDel_noAF

Pathogenic

0.57

CADD

Pathogenic

DANN

Pathogenic

1.0

DEOGEN2

Pathogenic

1.0

D;D;D;.;.

Eigen

Pathogenic

1.1

Eigen_PC

Pathogenic

0.98

FATHMM_MKL

Pathogenic

0.98

LIST_S2

Uncertain

0.95

.;.;D;D;D

M_CAP

Pathogenic

0.50

MetaRNN

Pathogenic

0.99

D;D;D;D;D

MetaSVM

Pathogenic

0.98

MutationAssessor

Pathogenic

4.3

H;H;H;.;.

MutationTaster

Benign

1.0

D;D;D;D

PrimateAI

Pathogenic

0.86

PROVEAN

Uncertain

-3.7

D;D;D;D;D

REVEL

Pathogenic

0.97

Sift

Uncertain

0.0010

D;D;D;D;D

Sift4G

Pathogenic

0.0010

D;D;D;D;D

Polyphen

1.0

D;D;D;.;.

Vest4

0.96

MutPred

0.96

Gain of ubiquitination at E191 (P = 0.0138);Gain of ubiquitination at E191 (P = 0.0138);Gain of ubiquitination at E191 (P = 0.0138);Gain of ubiquitination at E191 (P = 0.0138);.;

MVP

0.99

MPC

0.65

ClinPred

1.0

GERP RS

5.7

Varity_R

0.98

gMVP

0.97

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

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