NM_000474.4:c.309C>G

Variant names:

• chr7-19117013-G-C
• rs104894054
• NM_000474.4:c.309C>G

Variant summary

Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PVS1 PM2 PP5_Very_Strong

The NM_000474.4(TWIST1):​c.309C>G​(p.Tyr103*) variant causes a stop gained change involving the alteration of a non-conserved nucleotide. 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: 32)
• Consequence: TWIST1 NM_000474.4 stop_gained
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:7
• Conservation: PhyloP100: 1.83

Genes affected

TWIST1 (HGNC:12428): (twist family bHLH transcription factor 1) This gene encodes a basic helix-loop-helix (bHLH) transcription factor that plays an important role in embryonic development. The encoded protein forms both homodimers and heterodimers that bind to DNA E box sequences and regulate the transcription of genes involved in cranial suture closure during skull development. This protein may also regulate neural tube closure, limb development and brown fat metabolism. This gene is hypermethylated and overexpressed in multiple human cancers, and the encoded protein promotes tumor cell invasion and metastasis, as well as metastatic recurrence. Mutations in this gene cause Saethre-Chotzen syndrome in human patients, which is characterized by craniosynostosis, ptosis and hypertelorism. [provided by RefSeq, Jul 2020]

ACMG classification

Verdict is Pathogenic. Variant got 18 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. There are 21 pathogenic variants in the truncated region.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 7-19117013-G-C is Pathogenic according to our data. Variant chr7-19117013-G-C is described in ClinVar as [Likely_pathogenic]. Clinvar id is 802300.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr7-19117013-G-C is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TWIST1	NM_000474.4	c.309C>G	p.Tyr103*	stop_gained	Exon 1 of 2	ENST00000242261.6	NP_000465.1
TWIST1	NR_149001.2	n.624C>G		non_coding_transcript_exon_variant	Exon 1 of 3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TWIST1	ENST00000242261.6	c.309C>G	p.Tyr103*	stop_gained	Exon 1 of 2	1	NM_000474.4	ENSP00000242261.5
TWIST1	ENST00000354571.5	n.105C>G		non_coding_transcript_exon_variant	Exon 1 of 3	2		ENSP00000346582.5
TWIST1	ENST00000443687.5	n.-91C>G		upstream_gene_variant		4		ENSP00000416986.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:7

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

TWIST1-related craniosynostosis Pathogenic:2

Jul 17, 2023

Victorian Clinical Genetics Services, Murdoch Childrens Research Institute

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Based on the classification scheme VCGS_Germline_v1.3.4, this variant is classified as Pathogenic. Following criteria are met: 0102 - Loss of function are known mechanisms of disease in this gene and is associated with TWIST1-related craniosynostosis (MONDO:0007399; (GeneReviews). Dominant-negative is the suggested mechanism for Sweeney-Cox syndrome (MIM#617746; PMID: 28369379). (I) 0107 - This gene is associated with autosomal dominant disease. (I) 0204 - Variant is predicted to result in a truncated protein (premature termination codon is NOT located at least 54 nucleotides upstream of the final exon-exon junction) with at least 1/3 of the protein sequence affected. (SP) 0251 - This variant is heterozygous. (I) 0301 - Variant is absent from gnomAD (both v2 and v3). (SP) 0701 - Other downstream protein truncating variants comparable to the one identified in this case have very strong previous evidence for pathogenicity (DECIPHER). (SP) 0801 - This variant has strong previous evidence of pathogenicity in unrelated individuals. This variant, and alternative variants resulting in the same protein outcome (c.309C>A and c.308dup), have been observed in multiple individuals with craniosynostosis, including de novo events (PMIDs: 31837199, 32909287; ClinVar). (SP) 1208 - Inheritance information for this variant is not currently available in this individual. (I) Legend: (SP) - Supporting pathogenic, (I) - Information, (SB) - Supporting benign -

May 28, 2019

Mendelics

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Saethre-Chotzen syndrome Pathogenic:2

-

Department of Medical Genetics, Oslo University Hospital

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Sep 01, 2022

3billion

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The variant is not observed in the gnomAD v2.1.1 dataset. Stop-gained (nonsense) is predicted to result in a loss or disruption of normal protein function through nonsense-mediated decay (NMD) or protein truncation. Multiple pathogenic variants are reported downstream of the variant. The variant has been reported at least twice as pathogenic without evidence for the classification (ClinVar ID: VCV000802300 / PMID: 9585583). Therefore, this variant is classified as Pathogenic according to the recommendation of ACMG/AMP guideline. -

Neurodevelopmental delay Pathogenic:1

-

Centre de Biologie Pathologie Génétique, Centre Hospitalier Universitaire de Lille

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

not provided Pathogenic:1

Mar 23, 2024

GeneDx

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Nonsense variant predicted to result in protein truncation, as the last 100 amino acids are lost, and other loss-of-function variants have been reported downstream in HGMD; Not observed in large population cohorts (gnomAD); This variant is associated with the following publications: (PMID: 24127277, 19373776, 9585583, 31837199) -

Saethre-Chotzen syndrome;C4551902:TWIST1-related craniosynostosis Pathogenic:1

Jan 23, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change creates a premature translational stop signal (p.Tyr103*) in the TWIST1 gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in TWIST1 are known to be pathogenic (PMID: 10749989). This variant is not present in population databases (gnomAD no frequency). This premature translational stop signal has been observed in individual(s) with Saethre-Chotzen syndrome (PMID: 9585583). ClinVar contains an entry for this variant (Variation ID: 802300). For these reasons, this variant has been classified as Pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.58	D
BayesDel_noAF	Pathogenic	0.54
CADD	Pathogenic	41
DANN	Uncertain	0.99
Eigen	Pathogenic	0.78
Eigen_PC	Uncertain	0.57
FATHMM_MKL	Uncertain	0.88	D
Vest4		0.82
GERP RS		4.5

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: rs104894054; hg19: chr7-19156636;