NM_000474.4:c.261_276delGGGCGGCGGCGGCGGC

Variant names:

• chr7-19117044-CTGCCGCCGCCGCCGCC-CT
• NM_000474.4:c.262_276delGGCGGCGGCGGCGGC

Variant summary

Our verdict is Uncertain significance. The variant received 2 ACMG points: 2P and 0B. PM1

The NM_000474.4(TWIST1):​c.262_276delGGCGGCGGCGGCGGC​(p.Gly88_Gly92del) variant causes a conservative inframe deletion change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. It is difficult to determine the true allele frequency of this variant because it is of type DEL_BIG, and the frequency of such variant types in population databases may be underestimated and unreliable. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Synonymous variant affecting the same amino acid position (i.e. G88G) has been classified as Likely benign.

• Frequency: Genomes: not found (cov: 32)
• Consequence: TWIST1 NM_000474.4 conservative_inframe_deletion
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 3.11
• Publications: 0 publications found

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]

TWIST1 Gene-Disease associations (from GenCC):

• Saethre-Chotzen syndrome

  Inheritance: AD Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: ClinGen, Labcorp Genetics (formerly Invitae), Genomics England PanelApp, G2P, Orphanet, Laboratory for Molecular Medicine
• TWIST1-related craniosynostosis

  Inheritance: AD Classification: STRONG, MODERATE Submitted by: Labcorp Genetics (formerly Invitae), Genomics England PanelApp, ClinGen
• isolated brachycephaly

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• isolated plagiocephaly

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• isolated scaphocephaly

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• Sweeney-Cox syndrome

  Inheritance: AD Classification: LIMITED Submitted by: ClinGen

ACMG classification

Our verdict: Uncertain_significance. The variant received 2 ACMG points.

• PM1: In a chain Twist-related protein 1 (size 201) in uniprot entity TWST1_HUMAN there are 40 pathogenic changes around while only 6 benign (87%) in NM_000474.4

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000474.4. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	TWIST1	NM_000474.4	MANE Select	c.262_276delGGCGGCGGCGGCGGC	p.Gly88_Gly92del	conservative_inframe_deletion	Exon 1 of 2	NP_000465.1	Q15672
	TWIST1	NR_149001.2		n.577_591delGGCGGCGGCGGCGGC		non_coding_transcript_exon	Exon 1 of 3

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	TWIST1	ENST00000242261.6	TSL:1 MANE Select	c.262_276delGGCGGCGGCGGCGGC	p.Gly88_Gly92del	conservative_inframe_deletion	Exon 1 of 2	ENSP00000242261.5	Q15672
	TWIST1	ENST00000354571.5	TSL:2	n.58_72delGGCGGCGGCGGCGGC		non_coding_transcript_exon	Exon 1 of 3	ENSP00000346582.5	H7BY00
	TWIST1	ENST00000443687.5	TSL:4	n.-138_-124delGGCGGCGGCGGCGGC		upstream_gene	N/A	ENSP00000416986.1	H7C4D7

Frequencies

GnomAD3 genomes Cov.: 32

We have no GnomAD4 exomes data on this position. Probably position not covered by the project.

GnomAD4 genome Cov.: 32

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
PhyloP100		3.1

Splicing

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

MaxEntScan Visualizer can be used to analyze the impact of this mutation on the neighboring sequence.

Other links and lift over

hg19: chr7-19156667;