NM_001271893.4:c.229_234dupCAGCGC

Variant names:

• chr2-238848438-G-GAGCGCC
• rs869320750
• NM_001271893.4:c.229_234dupCAGCGC

Variant summary

Our verdict is Likely pathogenic. The variant received 6 ACMG points: 6P and 0B. PM2 PM4 PP3 PP5

The NM_001271893.4(TWIST2):​c.229_234dupCAGCGC​(p.Gln77_Arg78dup) variant causes a conservative inframe insertion 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 Pathogenic (no stars).

• Frequency: Genomes: not found (cov: 32)
• Consequence: TWIST2 NM_001271893.4 conservative_inframe_insertion
• Clinical Significance: Pathogenic no assertion criteria provided P:1
• Conservation: PhyloP100: 8.88
• Publications: 0 publications found

Genes affected

TWIST2 (HGNC:20670): (twist family bHLH transcription factor 2) The protein encoded by this gene is a basic helix-loop-helix type transcription factor and shares similarity with Twist. This protein may inhibit osteoblast maturation and maintain cells in a preosteoblast phenotype during osteoblast development. This gene may be upregulated in certain cancers. Mutations in this gene cause focal facial dermal dysplasia 3, Setleis type. Two transcript variants encoding the same protein have been found. [provided by RefSeq, Apr 2014]

TWIST2 Gene-Disease associations (from GenCC):

• ablepharon macrostomia syndrome

  Inheritance: AD Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Orphanet, G2P, Labcorp Genetics (formerly Invitae)
• Barber-Say syndrome

  Inheritance: AD Classification: STRONG, SUPPORTIVE Submitted by: Orphanet, Labcorp Genetics (formerly Invitae)
• focal facial dermal dysplasia type III

  Inheritance: AD, AR Classification: STRONG, SUPPORTIVE Submitted by: Orphanet, Labcorp Genetics (formerly Invitae), G2P

ACMG classification

Our verdict: Likely_pathogenic. The variant received 6 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PM4: Nonframeshift variant in NON repetitive region in NM_001271893.4.
• PP3: No computational evidence supports a deleterious effect, but strongly conserved according to phyloP
• PP5: Variant 2-238848438-G-GAGCGCC is Pathogenic according to our data. Variant chr2-238848438-G-GAGCGCC is described in ClinVar as Pathogenic. ClinVar VariationId is 208079.Status of the report is no_assertion_criteria_provided, 0 stars.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_001271893.4. 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
	TWIST2	NM_001271893.4	MANE Select	c.229_234dupCAGCGC	p.Gln77_Arg78dup	conservative_inframe_insertion	Exon 1 of 2	NP_001258822.1
	TWIST2	NM_057179.3		c.229_234dupCAGCGC	p.Gln77_Arg78dup	conservative_inframe_insertion	Exon 1 of 2	NP_476527.1

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	TWIST2	ENST00000612363.2	TSL:1 MANE Select	c.229_234dupCAGCGC	p.Gln77_Arg78dup	conservative_inframe_insertion	Exon 1 of 2	ENSP00000482581.1
	TWIST2	ENST00000448943.2	TSL:1	c.229_234dupCAGCGC	p.Gln77_Arg78dup	conservative_inframe_insertion	Exon 1 of 2	ENSP00000405176.2
	TWIST2	ENST00000710607.1		c.229_234dupCAGCGC	p.Gln77_Arg78dup	conservative_inframe_insertion	Exon 1 of 2	ENSP00000518373.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

ClinVar submissions as Germline

Significance: Pathogenic

Revision: no assertion criteria provided

Pathogenic	VUS	Benign	Condition
1	-	-	Barber-Say syndrome (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
PhyloP100		8.9
Mutation Taster		=17/83	disease causing (ClinVar)

Splicing

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

Other links and lift over

dbSNP: rs869320750; hg19: chr2-239757079;