2-203867965-G-T

Position:

• chr2-203867965-G-T

Variant summary

Our verdict is Benign. Variant got -7 ACMG points: 0P and 7B. BP4_Moderate BS1_Supporting BS2

The NM_005214.5(CTLA4):​c.23G>T​(p.Arg8Leu) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000821 in 1,461,776 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 12/21 in silico tools predict a benign 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. R8Q) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000082 (0 hom.)
• Consequence: CTLA4 NM_005214.5 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 1.99

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 Benign. Variant got -7 ACMG points.

• BP4: Computational evidence support a benign effect (MetaRNN=0.09263301).
• BS1: Variant frequency is greater than expected in population amr. gnomad4_exome allele frequency = 0.00000821 (12/1461776) while in subpopulation AMR AF= 0.000268 (12/44724). AF 95% confidence interval is 0.000154. There are 0 homozygotes in gnomad4_exome. There are 3 alleles in male gnomad4_exome subpopulation. Median coverage is 29. This position pass quality control queck. Existence of Clinvar submissions makes me limit the strength of this signal to Supporting
• BS2: High AC in GnomAdExome4 at 12 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
CTLA4	NM_005214.5	c.23G>T	p.Arg8Leu	missense_variant	1/4	ENST00000648405.2
CTLA4	NM_001037631.3	c.23G>T	p.Arg8Leu	missense_variant	1/3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
CTLA4	ENST00000648405.2	c.23G>T	p.Arg8Leu	missense_variant	1/4		NM_005214.5	P1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD3 exomes AF: 0.0000398 AC: 10 AN: 251380 Hom.: 0 AF XY: 0.0000221 AC XY: 3 AN XY: 135858

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.000289

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: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000821 AC: 12 AN: 1461776 Hom.: 0 Cov.: 29 AF XY: 0.00000413 AC XY: 3 AN XY: 727200

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.000268

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: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

Bravo AF: 0.00000756

ExAC AF: 0.0000494 AC: 6

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Autoimmune lymphoproliferative syndrome due to CTLA4 haploinsufficiency Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Nov 20, 2022

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 are either unavailable or do not agree on the potential impact of this missense change (SIFT: "Deleterious"; PolyPhen-2: "Benign"; Align-GVGD: "Class C0"). This variant has not been reported in the literature in individuals affected with CTLA4-related conditions. This variant is present in population databases (rs138279736, gnomAD 0.03%). This sequence change replaces arginine, which is basic and polar, with leucine, which is neutral and non-polar, at codon 8 of the CTLA4 protein (p.Arg8Leu). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.11
BayesDel_addAF	Benign	-0.32	T
BayesDel_noAF	Benign	-0.38
CADD	Benign	13
DANN	Uncertain	1.0
DEOGEN2	Benign	0.37	T;T;.;.;.
Eigen	Benign	-0.080
Eigen_PC	Benign	-0.20
FATHMM_MKL	Benign	0.37	N
LIST_S2	Benign	0.69	.;T;T;T;T
M_CAP	Benign	0.020	T
MetaRNN	Benign	0.093	T;T;T;T;T
MetaSVM	Benign	-1.0	T
MutationAssessor	Uncertain	2.2	M;M;M;M;M
MutationTaster	Benign	1.0	N;N;N
PrimateAI	Benign	0.25	T
PROVEAN	Benign	-1.5	.;N;N;.;D
REVEL	Benign	0.15
Sift	Uncertain	0.0050	.;D;D;.;D
Sift4G	Uncertain	0.016	.;D;D;.;D
Polyphen		0.96	D;D;.;.;P
Vest4		0.38, 0.47, 0.50
MutPred		0.44		Loss of solvent accessibility (P = 0.0052);Loss of solvent accessibility (P = 0.0052);Loss of solvent accessibility (P = 0.0052);Loss of solvent accessibility (P = 0.0052);Loss of solvent accessibility (P = 0.0052);
MVP		0.68
MPC		1.2
ClinPred		0.37	T
GERP RS		4.2
Varity_R		0.15
gMVP		0.53

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: rs138279736; hg19: chr2-204732688; COSMIC: COSV99865171; COSMIC: COSV99865171;