rs1553180295

Positions:

• chr1-40997509-C-A

Variant summary

Our verdict is Uncertain significance. Variant got 2 ACMG points: 2P and 0B. PM2

The NM_001905.4(CTPS1):​c.988C>A​(p.His330Asn) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: CTPS1 NM_001905.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 7.57

Genes affected

CTPS1 (HGNC:2519): (CTP synthase 1) This gene encodes an enzyme responsible for the catalytic conversion of UTP (uridine triphosphate) to CTP (cytidine triphospate). This reaction is an important step in the biosynthesis of phospholipids and nucleic acids. Activity of this proten is important in the immune system, and loss of function of this gene has been associated with immunodeficiency. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Jul 2014]

ACMG classification

Verdict is Uncertain_significance. Variant got 2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
CTPS1	NM_001905.4	c.988C>A	p.His330Asn	missense_variant	9/19	ENST00000650070.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
CTPS1	ENST00000650070.2	c.988C>A	p.His330Asn	missense_variant	9/19		NM_001905.4	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Severe combined immunodeficiency due to CTPS1 deficiency Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Dec 26, 2017

This variant has not been reported in the literature in individuals with CTPS1-related disease. 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. Algorithms developed to predict the effect of missense changes on protein structure and function do not agree on the potential impact of this missense change (SIFT: "Tolerated"; PolyPhen-2: "Possibly Damaging"; Align-GVGD: "Class C25"). This variant is not present in population databases (ExAC no frequency). This sequence change replaces histidine with asparagine at codon 330 of the CTPS1 protein (p.His330Asn). The histidine residue is moderately conserved and there is a small physicochemical difference between histidine and asparagine. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Uncertain	0.37
BayesDel_addAF	Pathogenic	0.18	D
BayesDel_noAF	Uncertain	0.020
CADD	Pathogenic	28
DANN	Uncertain	0.98
DEOGEN2	Pathogenic	0.80	D;D;.;D;.;D;D
Eigen	Uncertain	0.37
Eigen_PC	Uncertain	0.41
FATHMM_MKL	Pathogenic	0.97	D
M_CAP	Uncertain	0.21	D
MetaRNN	Uncertain	0.63	D;D;D;D;D;D;D
MetaSVM	Uncertain	0.51	D
MutationAssessor	Uncertain	2.0	M;M;.;M;.;M;.
MutationTaster	Benign	1.0	D;D;D
PrimateAI	Pathogenic	0.81	D
PROVEAN	Uncertain	-2.8	D;.;.;.;.;D;.
REVEL	Pathogenic	0.66
Sift	Benign	0.037	D;.;.;.;.;D;.
Sift4G	Benign	0.35	T;.;.;.;.;T;.
Polyphen		0.55	P;P;.;P;.;P;.
Vest4		0.75
MutPred		0.33		Loss of catalytic residue at K331 (P = 0.0905);Loss of catalytic residue at K331 (P = 0.0905);Loss of catalytic residue at K331 (P = 0.0905);Loss of catalytic residue at K331 (P = 0.0905);Loss of catalytic residue at K331 (P = 0.0905);Loss of catalytic residue at K331 (P = 0.0905);.;
MVP		0.90
MPC		1.9
ClinPred		0.95	D
GERP RS		4.9
Varity_R		0.77
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: rs1553180295; hg19: chr1-41463181;