rs797046035

chr18-55228275-C-CG

Variant summary

Our verdict is Pathogenic. Variant got 12 ACMG points: 12P and 0B. PVS1_Moderate PM2 PP5_Very_Strong

The NM_001083962.2(TCF4):c.1965_1966insC(p.Gly656ArgfsTer55) variant causes a frameshift change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Pathogenic (★★★). Synonymous variant affecting the same amino acid position (i.e. A655A) has been classified as Likely benign.

• Frequency: Genomes: not found (cov: 32)
• Consequence: TCF4 NM_001083962.2 frameshift
• Clinical Significance: Pathogenic reviewed by expert panel P:3
• Conservation: PhyloP100: -0.169

Genes affected

TCF4 (HGNC:11634): (transcription factor 4) This gene encodes transcription factor 4, a basic helix-loop-helix transcription factor. The encoded protein recognizes an Ephrussi-box ('E-box') binding site ('CANNTG') - a motif first identified in immunoglobulin enhancers. This gene is broadly expressed, and may play an important role in nervous system development. Defects in this gene are a cause of Pitt-Hopkins syndrome. In addition, an intronic CTG repeat normally numbering 10-37 repeat units can expand to >50 repeat units and cause Fuchs endothelial corneal dystrophy. Multiple alternatively spliced transcript variants that encode different proteins have been described. [provided by RefSeq, Jul 2016]

ACMG classification

Verdict is Pathogenic. Variant got 12 ACMG points.

• PVS1: Loss of function variant, product does not undergo nonsense mediated mRNA decay. Variant is located in the 3'-most 50 bp of the penultimate exon, not predicted to undergo nonsense mediated mRNA decay. Fraction of 0.0253 CDS is truncated, and there are 2 pathogenic variants in the truncated region.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 18-55228275-C-CG is Pathogenic according to our data. Variant chr18-55228275-C-CG is described in ClinVar as [Pathogenic]. Clinvar id is 212379.Status of the report is reviewed_by_expert_panel, 3 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
TCF4	NM_001083962.2	c.1965_1966insC	p.Gly656ArgfsTer55	frameshift_variant	19/20	ENST00000354452.8

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
TCF4	ENST00000354452.8	c.1965_1966insC	p.Gly656ArgfsTer55	frameshift_variant	19/20	5	NM_001083962.2	P3

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 30

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:3

Revision: reviewed by expert panel

Submissions by phenotype

Pitt-Hopkins syndrome Pathogenic:3

Pathogenic, reviewed by expert panel	curation	ClinGen Rett and Angelman-like Disorders Variant Curation Expert Panel	Mar 26, 2021	The p.Gly656Argfs*55 variant in TCF4 is predicted to cause a premature stop codon that leads to a truncated or absent protein in a gene where loss-of-function is an established mechanism. There is significant evidence that loss of this region of the gene is pathogenic (PVS1). The p.Gly656Argfs*55 variant in TCF4 has been reported as a de novo occurrence (biological parentage confirmed) in an individual with Pitt-Hopkins syndrome (PMID 25326637) (PS2). This variant is absent from gnomAD (PM2_supporting). In summary, the p.Gly656Argfs*55 variant in TCF4 is classified as Pathogenic for Pitt-Hopkins syndrome based on the ACMG/AMP criteria (PVS1, PS2, PM2_supporting). -
Pathogenic, criteria provided, single submitter	clinical testing	UCLA Clinical Genomics Center, UCLA	Jun 10, 2014	- -
Likely pathogenic, criteria provided, single submitter	clinical testing	Genetic Services Laboratory, University of Chicago	Jun 03, 2015	- -

Computational scores

Source: dbNSFP v4.3

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.020		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: rs797046035; hg19: chr18-52895506;