4-122612851-C-A

Position:

• chr4-122612851-C-A

Variant summary

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

The NM_021803.4(IL21):​c.438G>T​(p.Lys146Asn) variant causes a missense, splice region change. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: IL21 NM_021803.4 missense, splice_region
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 4.32

Genes affected

IL21 (HGNC:6005): (interleukin 21) This gene encodes a member of the common-gamma chain family of cytokines with immunoregulatory activity. The encoded protein plays a role in both the innate and adaptive immune responses by inducing the differentiation, proliferation and activity of multiple target cells including macrophages, natural killer cells, B cells and cytotoxic T cells. Dysregulation of this gene plays a role in multiple immune-mediated diseases including lupus, psoriasis and chronic inflammatory diseases. Alternatively spliced transcript variants encoding multiple isoforms have been observed for this gene. [provided by RefSeq, Dec 2011]

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	Protein	UniProt
IL21	NM_021803.4	c.438G>T	p.Lys146Asn	missense_variant, splice_region_variant	4/5	ENST00000648588.1	NP_068575.1
IL21	NM_001207006.3	c.438G>T	p.Lys146Asn	missense_variant	4/4		NP_001193935.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
IL21	ENST00000611104.2	c.438G>T	p.Lys146Asn	missense_variant	4/4	1		ENSP00000477555
IL21	ENST00000648588.1	c.438G>T	p.Lys146Asn	missense_variant, splice_region_variant	4/5		NM_021803.4	ENSP00000497915	P1
IL21	ENST00000647784.1	n.290G>T		splice_region_variant, non_coding_transcript_exon_variant	3/4

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

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Nov 20, 2020

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. 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: "Probably Damaging"; Align-GVGD: "Class C0"). This variant has not been reported in the literature in individuals with IL21-related conditions. This variant is not present in population databases (ExAC no frequency). This sequence change replaces lysine with asparagine at codon 146 of the IL21 protein (p.Lys146Asn). The lysine residue is highly conserved and there is a moderate physicochemical difference between lysine and asparagine. This variant also falls at the last nucleotide of exon 4, which is part of the consensus splice site for this exon. 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	0.69
BayesDel_addAF	Benign	-0.059	T
BayesDel_noAF	Benign	-0.32
CADD	Pathogenic	34
DANN	Uncertain	1.0
Eigen	Uncertain	0.52
Eigen_PC	Uncertain	0.50
FATHMM_MKL	Uncertain	0.93	D
LIST_S2	Benign	0.61	.;T;T
M_CAP	Benign	0.027	D
MetaRNN	Benign	0.29	T;T;T
MetaSVM	Benign	-0.46	T
MutationTaster	Benign	1.0	D
PrimateAI	Benign	0.44	T
PROVEAN	Uncertain	-3.8	.;D;.
REVEL	Benign	0.11
Sift	Uncertain	0.0080	.;D;.
Sift4G	Pathogenic	0.0	.;D;D
Vest4		0.37, 0.40
MVP		0.43
MPC		1.8
ClinPred		0.99	D
GERP RS		4.8
gMVP		0.54

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.92
SpliceAI score (max)		0.88		Details are displayed if max score is > 0.2
DS_DL_spliceai		0.88		Position offset: 0

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

Publications

No publications associated with this variant yet.

Other links and lift over

hg19: chr4-123534006; COSMIC: COSV52645781;