rs1290474919

chr2-210605094-A-G

Variant summary

Our verdict is Uncertain significance. Variant got 4 ACMG points: 4P and 0B. PM2 PP3 PP5

The NM_001875.5(CPS1):c.1837-8A>G variant causes a splice region, splice polypyrimidine tract, intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000558 in 1,611,582 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 2/2 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

• Frequency:
  • Genomes: 𝑓 0.000013 (0 hom., cov: 32)
  • Exomes 𝑓: 0.0000048 (0 hom.)
• Consequence: CPS1 NM_001875.5 splice_region, splice_polypyrimidine_tract, intron
• Scores: Splicing: ADA: 0.9982
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:2 U:1
• Conservation: PhyloP100: 1.66

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 4 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: Splicing scoreres supports a deletorius effect: Scorers claiming Pathogenic: dbscSNV1_ADA, dbscSNV1_RF. No scorers claiming Uncertain. No scorers claiming Benign.
• PP5: Variant 2-210605094-A-G is Pathogenic according to our data. Variant chr2-210605094-A-G is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 558118.We mark this variant Likely_pathogenic, oryginal submissions are: {Pathogenic=1, Likely_pathogenic=1, Uncertain_significance=1}. Variant chr2-210605094-A-G is described in Lovd as [Pathogenic]. Variant chr2-210605094-A-G is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
CPS1	NM_001875.5	c.1837-8A>G		splice_region_variant, splice_polypyrimidine_tract_variant, intron_variant		ENST00000233072.10

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
CPS1	ENST00000233072.10	c.1837-8A>G		splice_region_variant, splice_polypyrimidine_tract_variant, intron_variant		1	NM_001875.5	P1

Frequencies

GnomAD3 genomes AF: 0.0000132 AC: 2 AN: 151880 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.00

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: 0.0000295

Gnomad OTH AF: 0.00

GnomAD4 exome AF: 0.00000480 AC: 7 AN: 1459584 Hom.: 0 Cov.: 30 AF XY: 0.00000689 AC XY: 5 AN XY: 726176

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: 0.00000630

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome AF: 0.0000132 AC: 2 AN: 151998 Hom.: 0 Cov.: 32 AF XY: 0.0000135 AC XY: 1 AN XY: 74296

Gnomad4 AFR AF: 0.00

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: 0.0000295

Gnomad4 OTH AF: 0.00

Bravo AF: 0.00000378

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:2 Uncertain:1

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Congenital hyperammonemia, type I Pathogenic:1 Uncertain:1

Likely pathogenic, criteria provided, single submitter	clinical testing	Invitae	Apr 14, 2023	In summary, the currently available evidence indicates that the variant is pathogenic, but additional data are needed to prove that conclusively. Therefore, this variant has been classified as Likely Pathogenic. Studies have shown that this variant results in retention of part of intron 16 and introduces a premature termination codon (PMID: 16737834, 32154057). The resulting mRNA is expected to undergo nonsense-mediated decay. ClinVar contains an entry for this variant (Variation ID: 558118). This variant has been observed in individuals with CPS1 deficiency (PMID: 16737834, 28526534, 32154057, 33309754). This variant is not present in population databases (gnomAD no frequency). This sequence change falls in intron 16 of the CPS1 gene. It does not directly change the encoded amino acid sequence of the CPS1 protein. RNA analysis indicates that this variant induces altered splicing and may result in an absent or disrupted protein product. -
Uncertain significance, criteria provided, single submitter	clinical testing	Counsyl	Apr 27, 2018	- -

Pulmonary hypertension, neonatal, susceptibility to Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Baylor Genetics

Aug 28, 2023

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.59
Cadd	Uncertain	24
Dann	Benign	0.53

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.91
SpliceAI score (max)		0.99		Details are displayed if max score is > 0.2
DS_AG_spliceai		0.99		Position offset: 1
DS_AL_spliceai		0.88		Position offset: 8

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

Publications

LitVar

Other links and lift over

dbSNP: rs1290474919; hg19: chr2-211469818;