1-40984959-G-A

Position:

• chr1-40984959-G-A

Variant summary

Our verdict is Likely pathogenic. Variant got 6 ACMG points: 6P and 0B. PM2 PP3_Strong

The NM_001905.4(CTPS1):​c.305G>A​(p.Arg102Gln) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000139 in 1,434,754 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 (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R102W) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: CTPS1 NM_001905.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 9.52

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 Likely_pathogenic. Variant got 6 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.983

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
CTPS1	NM_001905.4	c.305G>A	p.Arg102Gln	missense_variant	3/19	ENST00000650070.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
CTPS1	ENST00000650070.2	c.305G>A	p.Arg102Gln	missense_variant	3/19		NM_001905.4	P1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD3 exomes AF: 0.00000821 AC: 2 AN: 243528 Hom.: 0 AF XY: 0.00000760 AC XY: 1 AN XY: 131602

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: 0.0000352

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00000892

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000139 AC: 2 AN: 1434754 Hom.: 0 Cov.: 30 AF XY: 0.00000141 AC XY: 1 AN XY: 709982

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: 0.0000120

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 9.14e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

ExAC AF: 0.0000165 AC: 2

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

Labcorp Genetics (formerly Invitae), Labcorp

Dec 11, 2023

This sequence change replaces arginine, which is basic and polar, with glutamine, which is neutral and polar, at codon 102 of the CTPS1 protein (p.Arg102Gln). This variant is present in population databases (rs765840007, gnomAD 0.004%). This variant has not been reported in the literature in individuals affected with CTPS1-related conditions. ClinVar contains an entry for this variant (Variation ID: 1933794). An algorithm developed to predict the effect of missense changes on protein structure and function (PolyPhen-2) suggests that this variant is likely to be disruptive. 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	Pathogenic	0.89
BayesDel_addAF	Pathogenic	0.31	D
BayesDel_noAF	Pathogenic	0.31
CADD	Pathogenic	34
DANN	Pathogenic	1.0
DEOGEN2	Pathogenic	0.82	D;D;.;D;.;.;D
Eigen	Pathogenic	1.2
Eigen_PC	Pathogenic	1.1
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Pathogenic	0.99	.;.;D;.;D;D;D
M_CAP	Uncertain	0.17	D
MetaRNN	Pathogenic	0.98	D;D;D;D;D;D;D
MetaSVM	Uncertain	0.54	D
MutationAssessor	Pathogenic	4.1	H;H;.;H;.;.;H
MutationTaster	Benign	1.0	D;D;D;D
PrimateAI	Uncertain	0.78	T
PROVEAN	Uncertain	-3.8	D;.;.;.;.;.;D
REVEL	Uncertain	0.64
Sift	Pathogenic	0.0	D;.;.;.;.;.;D
Sift4G	Pathogenic	0.0	D;.;.;.;.;.;D
Polyphen		1.0	D;D;.;D;.;.;D
Vest4		0.94
MutPred		0.94		Gain of ubiquitination at K100 (P = 0.0482);Gain of ubiquitination at K100 (P = 0.0482);Gain of ubiquitination at K100 (P = 0.0482);Gain of ubiquitination at K100 (P = 0.0482);Gain of ubiquitination at K100 (P = 0.0482);Gain of ubiquitination at K100 (P = 0.0482);Gain of ubiquitination at K100 (P = 0.0482);
MVP		0.94
MPC		2.3
ClinPred		1.0	D
GERP RS		5.6
Varity_R		0.95
gMVP		0.93

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: rs765840007; hg19: chr1-41450631;