rs372128852

Variant summary

Our verdict is Pathogenic. The variant received 14 ACMG points: 14P and 0B. PM2PP3_StrongPP5_Very_Strong

The NM_054012.4(ASS1):​c.970+5G>A variant causes a splice region, intron change. The variant allele was found at a frequency of 0.0000161 in 1,613,932 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Likely pathogenic (★★).

Frequency

Genomes: 𝑓 0.000013 ( 0 hom., cov: 32)
Exomes 𝑓: 0.000016 ( 0 hom. )

Consequence

ASS1
NM_054012.4 splice_region, intron

Scores

2
Splicing: ADA: 1.000
2

Clinical Significance

Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:11

Conservation

PhyloP100: 5.54

Publications

1 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

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Pathogenic. The variant received 14 ACMG points.

PM2
Very rare variant in population databases, with high coverage;
PP3
Splicing predictors support a deleterious effect. Scorers claiming Pathogenic: dbscSNV1_ADA, dbscSNV1_RF, max_spliceai. No scorers claiming Uncertain. No scorers claiming Benign.
PP5
Variant 9-130489469-G-A is Pathogenic according to our data. Variant chr9-130489469-G-A is described in ClinVar as Pathogenic/Likely_pathogenic. ClinVar VariationId is 265962.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
ASS1NM_054012.4 linkc.970+5G>A splice_region_variant, intron_variant Intron 12 of 14 ENST00000352480.10 NP_446464.1
ASS1NM_000050.4 linkc.970+5G>A splice_region_variant, intron_variant Intron 13 of 15 NP_000041.2

Ensembl

Gene Transcript HGVSc HGVSp Effect Exon rank TSL MANE Protein Appris UniProt
ASS1ENST00000352480.10 linkc.970+5G>A splice_region_variant, intron_variant Intron 12 of 14 1 NM_054012.4 ENSP00000253004.6

Frequencies

GnomAD3 genomes
AF:
0.0000131
AC:
2
AN:
152118
Hom.:
0
Cov.:
32
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:
0.0000147
Gnomad OTH
AF:
0.00
GnomAD2 exomes
AF:
0.0000159
AC:
4
AN:
251104
AF XY:
0.0000221
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:
0.0000264
Gnomad OTH exome
AF:
0.00
GnomAD4 exome
AF:
0.0000164
AC:
24
AN:
1461814
Hom.:
0
Cov.:
33
AF XY:
0.0000165
AC XY:
12
AN XY:
727214
show subpopulations
African (AFR)
AF:
0.00
AC:
0
AN:
33478
American (AMR)
AF:
0.00
AC:
0
AN:
44724
Ashkenazi Jewish (ASJ)
AF:
0.0000383
AC:
1
AN:
26134
East Asian (EAS)
AF:
0.00
AC:
0
AN:
39698
South Asian (SAS)
AF:
0.0000116
AC:
1
AN:
86258
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
53380
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
5766
European-Non Finnish (NFE)
AF:
0.0000189
AC:
21
AN:
1111984
Other (OTH)
AF:
0.0000166
AC:
1
AN:
60392
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.471
Heterozygous variant carriers
0
2
4
6
8
10
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance

Age Distribution

Exome Het
Variant carriers
0
2
4
6
8
10
<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:
0.0000131
AC:
2
AN:
152118
Hom.:
0
Cov.:
32
AF XY:
0.00
AC XY:
0
AN XY:
74284
show subpopulations
⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5.
African (AFR)
AF:
0.00
AC:
0
AN:
41416
American (AMR)
AF:
0.00
AC:
0
AN:
15278
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
3468
East Asian (EAS)
AF:
0.000193
AC:
1
AN:
5184
South Asian (SAS)
AF:
0.00
AC:
0
AN:
4822
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
10598
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
316
European-Non Finnish (NFE)
AF:
0.0000147
AC:
1
AN:
68032
Other (OTH)
AF:
0.00
AC:
0
AN:
2092
⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5. (p-value = 0.00000037155), which strongly suggests a high chance of mosaicism in these individuals.
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.325
Heterozygous variant carriers
0
0
1
1
2
2
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance

Age Distribution

Genome Het
Variant carriers
0
2
4
6
8
10
<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:
0.0000436
Hom.:
0
Bravo
AF:
0.00000756
Asia WGS
AF:
0.000289
AC:
1
AN:
3478
EpiCase
AF:
0.0000545
EpiControl
AF:
0.00

ClinVar

Significance: Pathogenic/Likely pathogenic
Submissions summary: Pathogenic:11
Revision: criteria provided, multiple submitters, no conflicts
LINK: link

Submissions by phenotype

Citrullinemia type I Pathogenic:8
Jan 03, 2022
3billion
Significance:Likely pathogenic
Review Status:criteria provided, single submitter
Collection Method:clinical testing

The variant has been reported at least twice as pathogenic/likely pathogenic with clinical assertions and evidence for the classification (PMID_11941481, ClinVar ID: VCV000265962). The variant has been reported to be in trans as homozygous in at least one similarly affected unrelated individual (PMID: 7557970, PM3_P). In silico prediction tools predicted that this variant influenced pre-mRNA splicing, resulting in aberrant splicing (SPLICEAI: 0.92>=0.8, PP3_P). It is observed at an extremely low frequency in the gnomAD v2.1.1 dataset (total allele frequency: 0.000018, PM2_M). Therefore, this variant is classified as likely pathogenic according to the recommendation of ACMG/AMP guideline. -

Jan 12, 2024
Baylor Genetics
Significance:Pathogenic
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

Apr 01, 2002
OMIM
Significance:Pathogenic
Review Status:no assertion criteria provided
Collection Method:literature only

- -

Mar 11, 2021
Revvity Omics, Revvity
Significance:Likely pathogenic
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

Sep 01, 2016
GeneReviews
Significance:Pathogenic
Review Status:no assertion criteria provided
Collection Method:literature only

- -

Mar 31, 2017
Counsyl
Significance:Likely pathogenic
Review Status:no assertion criteria provided
Collection Method:clinical testing

This submission and the accompanying classification are no longer maintained by the submitter. For more information on current observations and classification, please contact variantquestions@myriad.com. -

Apr 02, 2020
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.970+5G>A alters a conserved nucleotide located close to a canonical splice site and therefore could affect mRNA splicing, leading to a significantly altered protein sequence. Several computational tools predict a significant impact on normal splicing: Four predict that the variant abolishes or weakens a 5' splicing donor site. At least one publication reports experimental evidence that this variant affects mRNA splicing (e.g. Kobayashi_1995). The variant allele was found at a frequency of 1.6e-05 in 251104 control chromosomes (gnomAD). c.970+5G>A has been reported in the literature in multiple individuals affected with Citrullinemia Type I (e.g. Kobayashi_1995, Haberle_2002, Gao_2003, Diez-Fernandez_2016). These data indicate that the variant is very likely to be associated with disease. Four other clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014 without evidence for independent evaluation. All laboratories classified the variant as pathogenic/likely pathogenic. Based on the evidence outlined above, the variant was classified as pathogenic. -

Oct 31, 2018
Fulgent Genetics, Fulgent Genetics
Significance:Likely pathogenic
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

Citrullinemia Pathogenic:1
Mar 17, 2024
Labcorp Genetics (formerly Invitae), Labcorp
Significance:Pathogenic
Review Status:criteria provided, single submitter
Collection Method:clinical testing

This sequence change falls in intron 13 of the ASS1 gene. It does not directly change the encoded amino acid sequence of the ASS1 protein. It affects a nucleotide within the consensus splice site. This variant is present in population databases (rs372128852, gnomAD 0.003%). This variant has been observed in individual(s) with classic citrullinemia (PMID: 7557970, 11941481, 16475226; Invitae). ClinVar contains an entry for this variant (Variation ID: 265962). Variants that disrupt the consensus splice site are a relatively common cause of aberrant splicing (PMID: 17576681, 9536098). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. For these reasons, this variant has been classified as Pathogenic. -

See cases Pathogenic:1
Mar 29, 2022
Laboratorio de Genetica e Diagnostico Molecular, Hospital Israelita Albert Einstein
Significance:Pathogenic
Review Status:criteria provided, single submitter
Collection Method:clinical testing

ACMG classification criteria: PS3, PS4, PM2, PM3 -

not provided Pathogenic:1
Mar 01, 2023
GeneDx
Significance:Likely pathogenic
Review Status:criteria provided, single submitter
Collection Method:clinical testing

Published functional studies demonstrate that the variant results in 132 bp deletion in exon 13 (Kobayashi et al., 1995); Not observed at significant frequency in large population cohorts (gnomAD); This variant is associated with the following publications: (PMID: 7557970, 32778825, 28111830) -

Computational scores

Source: dbNSFP v4.3

Name
Calibrated prediction
Score
Prediction
BayesDel_noAF
Benign
-0.37
CADD
Benign
5.8
DANN
Benign
0.91
PhyloP100
5.5
Mutation Taster
=1/99
disease causing (ClinVar)

Splicing

Name
Calibrated prediction
Score
Prediction
dbscSNV1_ADA
Pathogenic
1.0
dbscSNV1_RF
Pathogenic
1.0
SpliceAI score (max)
0.92
Details are displayed if max score is > 0.2
DS_DL_spliceai
0.92
Position offset: -5

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

Publications

Other links and lift over

dbSNP: rs372128852; hg19: chr9-133364856; API