rs770935194

Variant names:

• chr2-210582674-A-G
• rs770935194
• NM_001875.5:c.586A>G

Variant summary

Our verdict is Uncertain significance. Variant got 5 ACMG points: 5P and 0B. PM1 PM2 PP3

The NM_001875.5(CPS1):​c.586A>G​(p.Asn196Asp) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000144 in 1,461,130 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 Uncertain significance (★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.000014 (0 hom.)
• Consequence: CPS1 NM_001875.5 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:2
• Conservation: PhyloP100: 8.95

Genes affected

CPS1 (HGNC:2323): (carbamoyl-phosphate synthase 1) The mitochondrial enzyme encoded by this gene catalyzes synthesis of carbamoyl phosphate from ammonia and bicarbonate. This reaction is the first committed step of the urea cycle, which is important in the removal of excess urea from cells. The encoded protein may also represent a core mitochondrial nucleoid protein. Three transcript variants encoding different isoforms have been found for this gene. The shortest isoform may not be localized to the mitochondrion. Mutations in this gene have been associated with carbamoyl phosphate synthetase deficiency, susceptibility to persistent pulmonary hypertension, and susceptibility to venoocclusive disease after bone marrow transplantation.[provided by RefSeq, May 2010]

ACMG classification

Verdict is Uncertain_significance. Variant got 5 ACMG points.

• PM1: In a region_of_interest Anthranilate phosphoribosyltransferase homolog (size 179) in uniprot entity CPSM_HUMAN there are 22 pathogenic changes around while only 1 benign (96%) in NM_001875.5
• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.832

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
CPS1	NM_001875.5	c.586A>G	p.Asn196Asp	missense_variant	Exon 6 of 38	ENST00000233072.10	NP_001866.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
CPS1	ENST00000233072.10	c.586A>G	p.Asn196Asp	missense_variant	Exon 6 of 38	1	NM_001875.5	ENSP00000233072.5

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD3 exomes AF: 0.00000797 AC: 2 AN: 251092 Hom.: 0 AF XY: 0.0000147 AC XY: 2 AN XY: 135682

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: 0.0000176

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.0000144 AC: 21 AN: 1461130 Hom.: 0 Cov.: 30 AF XY: 0.0000206 AC XY: 15 AN XY: 726866

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: 0.0000180

Gnomad4 OTH exome AF: 0.0000166

GnomAD4 genome Cov.: 32

ExAC AF: 0.00000824 AC: 1

EpiCase AF: 0.000109

EpiControl AF: 0.00

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, single submitter

Submissions by phenotype

Congenital hyperammonemia, type I Uncertain:2

Jan 25, 2021

Natera, Inc.

Significance: Uncertain significance

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

Sep 01, 2021

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces asparagine with aspartic acid at codon 196 of the CPS1 protein (p.Asn196Asp). The asparagine residue is highly conserved and there is a small physicochemical difference between asparagine and aspartic acid. This variant is present in population databases (rs770935194, ExAC 0.002%). This variant has not been reported in the literature in individuals affected with CPS1-related conditions. Algorithms developed to predict the effect of missense changes on protein structure and function are either unavailable or do not agree on the potential impact of this missense change (SIFT: "Deleterious"; PolyPhen-2: "Probably Damaging"; Align-GVGD: "Class C0"). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may create or strengthen a splice site. In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.16
BayesDel_addAF	Uncertain	0.092	D
BayesDel_noAF	Benign	-0.090
CADD	Uncertain	25
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.77	.;D;T
Eigen	Pathogenic	0.84
Eigen_PC	Pathogenic	0.77
FATHMM_MKL	Uncertain	0.97	D
LIST_S2	Pathogenic	0.98	D;D;D
M_CAP	Uncertain	0.11	D
MetaRNN	Pathogenic	0.83	D;D;D
MetaSVM	Pathogenic	0.90	D
MutationAssessor	Uncertain	2.9	.;M;.
PrimateAI	Uncertain	0.50	T
PROVEAN	Pathogenic	-4.7	D;D;.
REVEL	Pathogenic	0.76
Sift	Uncertain	0.020	D;D;.
Sift4G	Uncertain	0.046	D;D;T
Polyphen		1.0	.;D;.
Vest4		0.72
MutPred		0.62		.;Loss of catalytic residue at N196 (P = 0.0666);Loss of catalytic residue at N196 (P = 0.0666);
MVP		0.95
MPC		0.88
ClinPred		0.98	D
GERP RS		4.7
Varity_R		0.89
gMVP		0.87

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

Other links and lift over

dbSNP: rs770935194; hg19: chr2-211447398;