rs1556329822

Variant names:

• chrX-71108347-C-T
• rs1556329822
• NM_000206.3:c.855-1G>A

Variant summary

Our verdict is Pathogenic. Variant got 12 ACMG points: 12P and 0B. PVS1 PM2 PP5_Moderate

The NM_000206.3(IL2RG):​c.855-1G>A variant causes a splice acceptor, intron change involving the alteration of a non-conserved nucleotide. 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 Pathogenic (★).

• Frequency: Genomes: not found (cov: 23)
• Consequence: IL2RG NM_000206.3 splice_acceptor, intron
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 3.51

Genes affected

IL2RG (HGNC:6010): (interleukin 2 receptor subunit gamma) The protein encoded by this gene is an important signaling component of many interleukin receptors, including those of interleukin -2, -4, -7 and -21, and is thus referred to as the common gamma chain. Mutations in this gene cause X-linked severe combined immunodeficiency (XSCID), as well as X-linked combined immunodeficiency (XCID), a less severe immunodeficiency disorder. [provided by RefSeq, Mar 2010]

ENSG00000285171 (HGNC:):

ACMG classification

Verdict is Pathogenic. Variant got 12 ACMG points.

• PVS1: Splicing +-2 bp (donor or acceptor) variant, LoF is a know mechanism of disease, Cryptic splice site detected, with MaxEntScore 5, offset of 1, new splice context is: cctctttctcccctgtcaAGacg. Cryptic site results in frameshift change. If cryptic site found is not functional and variant results in exon loss, it results in frameshift change.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant X-71108347-C-T is Pathogenic according to our data. Variant chrX-71108347-C-T is described in ClinVar as [Pathogenic]. Clinvar id is 463385.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
IL2RG	NM_000206.3	c.855-1G>A		splice_acceptor_variant, intron_variant	Intron 6 of 7	ENST00000374202.7	NP_000197.1
IL2RG	XM_047442089.1	c.758-1G>A		splice_acceptor_variant, intron_variant	Intron 5 of 6		XP_047298045.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
IL2RG	ENST00000374202.7	c.855-1G>A		splice_acceptor_variant, intron_variant	Intron 6 of 7	1	NM_000206.3	ENSP00000363318.3
ENSG00000285171	ENST00000646505.1	n.855-1G>A		splice_acceptor_variant, intron_variant	Intron 6 of 11			ENSP00000496673.1

Frequencies

GnomAD3 genomes Cov.: 23

GnomAD4 exome Cov.: 27

GnomAD4 genome Cov.: 23

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

Submissions by phenotype

X-linked severe combined immunodeficiency Pathogenic:1

Nov 15, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change affects an acceptor splice site in intron 6 of the IL2RG gene. RNA analysis indicates that disruption of this splice site induces altered splicing and likely disrupts the C-terminus of the protein. This variant is not present in population databases (gnomAD no frequency). Disruption of this splice site has been observed in individuals with clinical features of severe combined immunodeficiency (PMID: 28359783, 28747913; Invitae). ClinVar contains an entry for this variant (Variation ID: 463385). Studies have shown that disruption of this splice site results in skipping of exon 7 and introduces a new termination codon (PMID: 28359783). However the mRNA is not expected to undergo nonsense-mediated decay. For these reasons, this variant has been classified as Pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Benign	-0.13	T
BayesDel_noAF	Benign	-0.43
CADD	Pathogenic	34
DANN	Benign	0.97
FATHMM_MKL	Benign	0.67	D
GERP RS		4.2

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.87
SpliceAI score (max)		1.0		Details are displayed if max score is > 0.2
DS_AG_spliceai		0.98		Position offset: -2
DS_AL_spliceai		1.0		Position offset: -1

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

Publications

LitVar

Other links and lift over

dbSNP: rs1556329822; hg19: chrX-70328197;