rs575001023

Variant names:

Variant summary

Our verdict is Pathogenic. The variant received 17 ACMG points: 17P and 0B. PM1PM2PM5PP2PP3_ModeratePP5_Very_Strong

The NM_054012.4(ASS1):c.257G>A(p.Arg86His) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000682 in 1,612,430 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. R86C) has been classified as Pathogenic.

Frequency

Genomes: 𝑓 0.0000066 ( 0 hom., cov: 33)

Exomes 𝑓: 0.0000068 ( 0 hom. )

Consequence

ASS1
NM_054012.4 missense

Scores

Clinical Significance

Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:4O:1

Conservation

PhyloP100: 8.61

Publications

7 publications found

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 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

ASS1 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Pathogenic. The variant received 17 ACMG points.

PM1

In a hotspot region, there are 4 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 3 uncertain 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 chr9-130458482-C-T is described in ClinVar as [Pathogenic]. Clinvar id is 6332.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

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.

PP3

MetaRNN computational evidence supports a deleterious effect, 0.894

PP5

Variant 9-130458483-G-A is Pathogenic according to our data. Variant chr9-130458483-G-A is described in ClinVar as [Likely_pathogenic]. Clinvar id is 265960.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
ASS1	NM_054012.4 link	c.257G>A	p.Arg86His	missense_variant	Exon 4 of 15	ENST00000352480.10	NP_446464.1	P00966Q5T6L4
ASS1	NM_000050.4 link	c.257G>A	p.Arg86His	missense_variant	Exon 5 of 16		NP_000041.2	P00966Q5T6L4

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
ASS1	ENST00000352480.10 link	c.257G>A	p.Arg86His	missense_variant	Exon 4 of 15	1	NM_054012.4	ENSP00000253004.6		P00966

Frequencies

GnomAD3 genomes

AF:

0.00000657

AC:

AN:

152172

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.000193

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

GnomAD2 exomes

AF:

0.0000120

AC:

AN:

250838

AF XY:

0.0000147

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 FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000685

AC:

AN:

1460258

Hom.:

Cov.:

AF XY:

0.00000688

AC XY:

AN XY:

726456

show subpopulations

African (AFR)

AF:

0.0000299

AC:

AN:

33426

American (AMR)

AF:

0.00

AC:

AN:

44712

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26132

East Asian (EAS)

AF:

0.0000252

AC:

AN:

39700

South Asian (SAS)

AF:

0.0000348

AC:

AN:

86182

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53400

Middle Eastern (MID)

AF:

0.00

AC:

AN:

4626

European-Non Finnish (NFE)

AF:

0.00000360

AC:

AN:

1111832

Other (OTH)

AF:

0.0000166

AC:

AN:

60248

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.490

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

GnomAD4 genome

AF:

0.00000657

AC:

AN:

152172

Hom.:

Cov.:

AF XY:

0.0000135

AC XY:

AN XY:

74344

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

41450

American (AMR)

AF:

0.00

AC:

AN:

15280

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.000193

AC:

AN:

5170

South Asian (SAS)

AF:

0.00

AC:

AN:

4830

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10624

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

68024

Other (OTH)

AF:

0.00

AC:

AN:

2094

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.525

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Genome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

Alfa

AF:

0.00

Hom.:

ExAC

AF:

0.00000824

AC:

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:4Other:1

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Citrullinemia

Pathogenic:2

Sep 15, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

For these reasons, this variant has been classified as Pathogenic. This variant disrupts the p.Arg86 amino acid residue in ASS1. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 1943692, 25433810). 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) has been performed at Invitae for this missense variant, however the output from this modeling did not meet the statistical confidence thresholds required to predict the impact of this variant on ASS1 protein function. ClinVar contains an entry for this variant (Variation ID: 265960). This missense change has been observed in individual(s) with citrullinemia type I (PMID: 12815590, 28132756). This variant is present in population databases (rs575001023, gnomAD 0.01%). This sequence change replaces arginine, which is basic and polar, with histidine, which is basic and polar, at codon 86 of the ASS1 protein (p.Arg86His). -

Dec 18, 2024

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Variant summary: ASS1 c.257G>A (p.Arg86His) results in a non-conservative amino acid change located in the Arginosuccinate synthase N-terminal HUP domain (IPR048267) of the encoded protein sequence. Three of five in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 1.2e-05 in 250838 control chromosomes. c.257G>A has been reported in the literature in multiple homozygous or compound heterozygous individuals affected with Citrullinemia Type I (e.g. Gao_2003, Kose_2017, Liu_2021). These data indicate that the variant is very likely to be associated with disease. A different variant affecting the same codon has been classified as pathogenic by our lab (c.256C>T, p.Arg86Cys), supporting the critical relevance of codon 86 to ASS1 protein function. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. The following publications have been ascertained in the context of this evaluation (PMID: 12815590, 15580409, 28132756, 33617202). ClinVar contains an entry for this variant (Variation ID: 265960). Based on the evidence outlined above, the variant was classified as pathogenic. -

Citrullinemia type I

Pathogenic:1Other:1

GeneReviews

Significance:not provided

Review Status:no classification provided

Collection Method:literature only

- -

Feb 26, 2024

Baylor Genetics

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

not provided

Pathogenic:1

Sep 15, 2020

GeneDx

Significance:Likely pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Not observed at a significant frequency in large population cohorts (Lek et al., 2016); In silico analysis, which includes protein predictors and evolutionary conservation, supports a deleterious effect; This variant is associated with the following publications: (PMID: 12815590, 20301631, 19006241, 24508627, 18925679, 28132756, 28111830) -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Uncertain

0.48

BayesDel_addAF

Pathogenic

0.28

BayesDel_noAF

Pathogenic

0.37

CADD

Pathogenic

(source)

DANN

Uncertain

1.0

DEOGEN2

Pathogenic

0.97

D;D;D;.;.

Eigen

Uncertain

0.49

Eigen_PC

Uncertain

0.54

FATHMM_MKL

Uncertain

0.93

LIST_S2

Uncertain

0.88

.;.;D;D;D

M_CAP

Uncertain

0.12

MetaRNN

Pathogenic

0.89

D;D;D;D;D

MetaSVM

Uncertain

0.71

MutationAssessor

Pathogenic

3.0

M;M;M;.;.

PhyloP100

8.6

PrimateAI

Uncertain

0.76

PROVEAN

Uncertain

-4.0

D;D;D;D;D

REVEL

Pathogenic

0.80

Sift

Benign

0.22

T;T;T;T;T

Sift4G

Benign

0.30

T;T;T;T;T

Polyphen

0.58

P;P;P;.;.

Vest4

0.79

MutPred

0.81

Gain of catalytic residue at L88 (P = 0.1025);Gain of catalytic residue at L88 (P = 0.1025);Gain of catalytic residue at L88 (P = 0.1025);Gain of catalytic residue at L88 (P = 0.1025);Gain of catalytic residue at L88 (P = 0.1025);

MVP

0.94

MPC

0.41

ClinPred

0.87

GERP RS

4.9

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.7

Varity_R

0.84

gMVP

0.77

Mutation Taster

=5/95

disease causing (ClinVar)

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.040

Details are displayed if max score is > 0.2

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

Publications

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over