rs193922136

Positions:

• chrX-136659390-C-A
• chrX-136659390-C-T

Variant summary

Our verdict is Likely pathogenic. Variant got 8 ACMG points: 8P and 0B. PM1 PM2 PP3_Moderate PP5_Moderate

The NM_000074.3(CD40LG):​c.761C>A​(p.Thr254Lys) variant causes a missense change. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Likely pathogenic (★).

• Frequency: Genomes: not found (cov: 22)
• Consequence: CD40LG NM_000074.3 missense
• Clinical Significance: Likely pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 3.84

Genes affected

CD40LG (HGNC:11935): (CD40 ligand) The protein encoded by this gene is expressed on the surface of T cells. It regulates B cell function by engaging CD40 on the B cell surface. A defect in this gene results in an inability to undergo immunoglobulin class switch and is associated with hyper-IgM syndrome. [provided by RefSeq, Jul 2008]

ACMG classification

Verdict is Likely_pathogenic. Variant got 8 ACMG points.

• PM1: In a chain CD40 ligand, membrane form (size 260) in uniprot entity CD40L_HUMAN there are 19 pathogenic changes around while only 0 benign (100%) in NM_000074.3
• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.937
• PP5: Variant X-136659390-C-A is Pathogenic according to our data. Variant chrX-136659390-C-A is described in ClinVar as [Likely_pathogenic]. Clinvar id is 530671.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
CD40LG	NM_000074.3	c.761C>A	p.Thr254Lys	missense_variant	5/5	ENST00000370629.7	NP_000065.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
CD40LG	ENST00000370629.7	c.761C>A	p.Thr254Lys	missense_variant	5/5	1	NM_000074.3	ENSP00000359663	P1

Frequencies

GnomAD3 genomes Cov.: 22

GnomAD4 exome Cov.: 30

GnomAD4 genome Cov.: 22

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

Submissions by phenotype

Hyper-IgM syndrome type 1 Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Oct 31, 2018

In summary, the currently available evidence indicates that the variant is pathogenic, but additional data are needed to prove that conclusively. Therefore, this variant has been classified as Likely Pathogenic. A different missense substitution at this codon (p.Thr254Met) has been determined to be pathogenic (PMID: 8889581, 10484640, 25541662). This suggests that the threonine residue is critical for CD40LG protein function and that other missense substitutions at this position may also be pathogenic. Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may create or strengthen a 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 do not agree on the potential impact of this missense change (SIFT: "Deleterious"; PolyPhen-2: "Probably Damaging"; Align-GVGD: "Class C15"). This variant has has been reported to segregate with hyper IgM syndrome in a single family (Invitae). This variant is not present in population databases (ExAC no frequency). This sequence change replaces threonine with lysine at codon 254 of the CD40LG protein (p.Thr254Lys). The threonine residue is highly conserved and there is a moderate physicochemical difference between threonine and lysine. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.97
BayesDel_addAF	Pathogenic	0.46	D
BayesDel_noAF	Pathogenic	0.42
CADD	Uncertain	24
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.98	D;D
FATHMM_MKL	Uncertain	0.95	D
LIST_S2	Benign	0.76	T;T
M_CAP	Pathogenic	0.93	D
MetaRNN	Pathogenic	0.94	D;D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Uncertain	2.8	M;.
MutationTaster	Benign	0.99	D;D
PrimateAI	Uncertain	0.68	T
PROVEAN	Uncertain	-4.0	D;D
REVEL	Pathogenic	0.74
Sift	Uncertain	0.0020	D;D
Sift4G	Uncertain	0.0060	D;D
Polyphen		1.0	D;D
Vest4		0.83
MutPred		0.68		Gain of methylation at T254 (P = 0.0172);.;
MVP		0.95
MPC		1.4
ClinPred		0.99	D
GERP RS		5.5
Varity_R		0.99
gMVP		0.88

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: rs193922136; hg19: chrX-135741549; COSMIC: COSV65699024;