2-203868010-C-T

Variant summary

Our verdict is Uncertain significance. Variant got 0 ACMG points: 2P and 2B. PM2 BP4_Moderate

The NM_005214.5(CTLA4):c.68C>T(p.Thr23Ile) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,786 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 14/21 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: CTLA4 NM_005214.5 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: -0.119

Genes affected

CTLA4 (HGNC:2505): (cytotoxic T-lymphocyte associated protein 4) This gene is a member of the immunoglobulin superfamily and encodes a protein which transmits an inhibitory signal to T cells. The protein contains a V domain, a transmembrane domain, and a cytoplasmic tail. Alternate transcriptional splice variants, encoding different isoforms, have been characterized. The membrane-bound isoform functions as a homodimer interconnected by a disulfide bond, while the soluble isoform functions as a monomer. Mutations in this gene have been associated with insulin-dependent diabetes mellitus, Graves disease, Hashimoto thyroiditis, celiac disease, systemic lupus erythematosus, thyroid-associated orbitopathy, and other autoimmune diseases. [provided by RefSeq, Jul 2008]

ACMG classification

Verdict is Uncertain_significance. Variant got 0 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.084910065).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
CTLA4	NM_005214.5	c.68C>T	p.Thr23Ile	missense_variant	1/4	ENST00000648405.2
CTLA4	NM_001037631.3	c.68C>T	p.Thr23Ile	missense_variant	1/3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
CTLA4	ENST00000648405.2	c.68C>T	p.Thr23Ile	missense_variant	1/4		NM_005214.5	P1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD3 exomes AF: 0.00000398 AC: 1 AN: 251418 Hom.: 0 AF XY: 0.00000736 AC XY: 1 AN XY: 135880

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: 0.00000879

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461786 Hom.: 0 Cov.: 32 AF XY: 0.00000138 AC XY: 1 AN XY: 727208

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: 8.99e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

Bravo AF: 0.00000378

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Autoimmune lymphoproliferative syndrome due to CTLA4 haploinsuffiency Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Apr 06, 2020

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 (SIFT, PolyPhen-2, Align-GVGD) all suggest that this variant is likely to be tolerated, but these predictions have not been confirmed by published functional studies and their clinical significance is uncertain. This variant has not been reported in the literature in individuals with CTLA4-related conditions. This variant is not present in population databases (ExAC no frequency). This sequence change replaces threonine with isoleucine at codon 23 of the CTLA4 protein (p.Thr23Ile). The threonine residue is moderately conserved and there is a moderate physicochemical difference between threonine and isoleucine. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.081
BayesDel_addAF	Benign	-0.25	T
BayesDel_noAF	Benign	-0.60
Cadd	Benign	0.23
Dann	Benign	0.96
DEOGEN2	Benign	0.35	T;T;.;.;.
Eigen	Benign	-0.86
Eigen_PC	Benign	-0.89
FATHMM_MKL	Benign	0.092	N
M_CAP	Benign	0.012	T
MetaRNN	Benign	0.085	T;T;T;T;T
MetaSVM	Benign	-1.0	T
MutationAssessor	Benign	1.5	L;L;L;L;L
MutationTaster	Benign	1.0	N;N;N
PrimateAI	Benign	0.27	T
Polyphen		0.73	P;P;.;.;B
Vest4		0.080, 0.11, 0.12
MutPred		0.39		Loss of helix (P = 0.079);Loss of helix (P = 0.079);Loss of helix (P = 0.079);Loss of helix (P = 0.079);Loss of helix (P = 0.079);
MVP		0.25
MPC		0.73
ClinPred		0.052	T
GERP RS		3.3
Varity_R		0.036
gMVP		0.43

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: rs1365829864; hg19: chr2-204732733;