rs1553657438

chr2-203870937-A-G

Variant summary

Our verdict is Uncertain significance. Variant got 3 ACMG points: 3P and 0B. PM2 PP3

The NM_005214.5(CTLA4):c.457+4A>G variant causes a splice donor region, intron change. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: CTLA4 NM_005214.5 splice_donor_region, intron
• Scores: Splicing: ADA: 0.9185
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 4.61

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 3 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: Splicing scoreres supports a deletorius effect: Scorers claiming Pathogenic: dbscSNV1_RF, max_spliceai. No scorers claiming Uncertain. Scorers claiming Benign: dbscSNV1_ADA.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
CTLA4	NM_005214.5	c.457+4A>G		splice_donor_region_variant, intron_variant		ENST00000648405.2
CTLA4	NM_001037631.3	c.457+4A>G		splice_donor_region_variant, intron_variant

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
CTLA4	ENST00000648405.2	c.457+4A>G		splice_donor_region_variant, intron_variant			NM_005214.5	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 30

GnomAD4 genome Cov.: 32

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

Nov 08, 2017

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. Nucleotide substitutions within the consensus splice site are a relatively common cause of aberrant splicing (PMID: 17576681, 9536098). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site, but this prediction has not been confirmed by published transcriptional studies. This variant has not been reported in the literature in individuals with CTLA4-related disease. This variant is not present in population databases (ExAC no frequency). This sequence change falls in intron 2 of the CTLA4 gene. It does not directly change the encoded amino acid sequence of the CTLA4 protein, but it affects a nucleotide within the consensus splice site of the intron. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.39
Cadd	Benign	21
Dann	Benign	0.89

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Benign	0.92
dbscSNV1_RF	Pathogenic	0.81
SpliceAI score (max)		0.53		Details are displayed if max score is > 0.2
DS_DG_spliceai		0.31		Position offset: -11
DS_DL_spliceai		0.53		Position offset: -4

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

Publications

LitVar

Other links and lift over

dbSNP: rs1553657438; hg19: chr2-204735660;