3-177025520-C-T

Variant names:

• chr3-177025520-C-T
• rs2108374207
• NM_024665.7:c.1523G>A

Variant summary

Our verdict is Uncertain significance. The variant received 3 ACMG points: 3P and 0B. PM2 PP2

The NM_024665.7(TBL1XR1):​c.1523G>A​(p.Cys508Tyr) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: TBL1XR1 NM_024665.7 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 7.57
• Publications: 0 publications found

Genes affected

TBL1XR1 (HGNC:29529): (TBL1X/Y related 1) This gene is a member of the WD40 repeat-containing gene family and shares sequence similarity with transducin (beta)-like 1X-linked (TBL1X). The protein encoded by this gene is thought to be a component of both nuclear receptor corepressor (N-CoR) and histone deacetylase 3 (HDAC 3) complexes, and is required for transcriptional activation by a variety of transcription factors. Mutations in these gene have been associated with some autism spectrum disorders, and one finding suggests that haploinsufficiency of this gene may be a cause of intellectual disability with dysmorphism. Mutations in this gene as well as recurrent translocations involving this gene have also been observed in some tumors. [provided by RefSeq, Mar 2016]

TBL1XR1 Gene-Disease associations (from GenCC):

• complex neurodevelopmental disorder

  Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
• intellectual disability, autosomal dominant 41

  Inheritance: AD Classification: DEFINITIVE, STRONG, MODERATE Submitted by: G2P, Ambry Genetics, Labcorp Genetics (formerly Invitae)
• Pierpont syndrome

  Inheritance: AD Classification: DEFINITIVE, STRONG, MODERATE Submitted by: Ambry Genetics, Labcorp Genetics (formerly Invitae), G2P

ACMG classification

Our verdict: Uncertain_significance. The variant received 3 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant in the TBL1XR1 gene, where missense mutations are typically associated with disease (based on misZ statistic). The gene has 50 curated pathogenic missense variants (we use a threshold of 10). The gene has 2 curated benign missense variants. Gene score misZ: 4.2042 (above the threshold of 3.09). Trascript score misZ: 5.2877 (above the threshold of 3.09). GenCC associations: The gene is linked to complex neurodevelopmental disorder, intellectual disability, autosomal dominant 41, Pierpont syndrome.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TBL1XR1	NM_024665.7	c.1523G>A	p.Cys508Tyr	missense_variant	Exon 16 of 16	ENST00000457928.7	NP_078941.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TBL1XR1	ENST00000457928.7	c.1523G>A	p.Cys508Tyr	missense_variant	Exon 16 of 16	1	NM_024665.7	ENSP00000413251.3

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

Pierpont syndrome Uncertain:1

Jan 13, 2021

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

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 (SIFT, PolyPhen-2, Align-GVGD) all suggest that this variant is likely to be tolerated, but these predictions have not been confirmed by published functional studies and their clinical significance is uncertain. This variant has not been reported in the literature in individuals with TBL1XR1-related conditions. This variant is not present in population databases (ExAC no frequency). This sequence change replaces cysteine with tyrosine at codon 508 of the TBL1XR1 protein (p.Cys508Tyr). The cysteine residue is weakly conserved and there is a large physicochemical difference between cysteine and tyrosine. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.78
BayesDel_addAF	Pathogenic	0.37	D
BayesDel_noAF	Pathogenic	0.30
CADD	Uncertain	26
DANN	Uncertain	0.97
DEOGEN2	Uncertain	0.47	T;T
Eigen	Uncertain	0.27
Eigen_PC	Uncertain	0.41
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.95	.;D
M_CAP	Benign	0.051	D
MetaRNN	Uncertain	0.53	D;D
MetaSVM	Benign	-0.35	T
MutationAssessor	Benign	1.9	L;L
PhyloP100		7.6
PrimateAI	Pathogenic	0.95	D
PROVEAN	Pathogenic	-4.4	D;D
REVEL	Uncertain	0.54
Sift	Uncertain	0.021	D;D
Sift4G	Benign	0.24	T;T
Polyphen		0.56	P;P
Vest4		0.64
MutPred		0.47		Gain of phosphorylation at C508 (P = 0.0293);Gain of phosphorylation at C508 (P = 0.0293);
MVP		0.92
MPC		1.8
ClinPred		0.64	D
GERP RS		5.9
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.72
gMVP		0.84
Mutation Taster		=23/77	disease causing

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.010		Details are displayed if max score is > 0.2

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

Other links and lift over

dbSNP: rs2108374207; hg19: chr3-176743308;