chr1-218435974-TG-AT

Variant names:

• chr1-218435974-TG-AT
• rs1553303162
• NM_003238.6:c.759_760delTGinsAT

Variant summary

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

The NM_003238.6(TGFB2):​c.759_760delTGinsAT​(p.Asp254Tyr) variant causes a missense change involving the alteration of a 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 MNV, and the frequency of such variant types in population databases may be underestimated and unreliable. Variant has been reported in ClinVar as Uncertain significance (★). Synonymous variant affecting the same amino acid position (i.e. I253I) has been classified as Likely benign.

• Frequency: Genomes: not found (cov: 32)
• Consequence: TGFB2 NM_003238.6 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 7.38
• Publications: 0 publications found

Genes affected

TGFB2 (HGNC:11768): (transforming growth factor beta 2) This gene encodes a secreted ligand of the TGF-beta (transforming growth factor-beta) superfamily of proteins. Ligands of this family bind various TGF-beta receptors leading to recruitment and activation of SMAD family transcription factors that regulate gene expression. The encoded preproprotein is proteolytically processed to generate a latency-associated peptide (LAP) and a mature peptide, and is found in either a latent form composed of a mature peptide homodimer, a LAP homodimer, and a latent TGF-beta binding protein, or in an active form consisting solely of the mature peptide homodimer. The mature peptide may also form heterodimers with other TGF-beta family members. Disruption of the TGF-beta/SMAD pathway has been implicated in a variety of human cancers. A chromosomal translocation that includes this gene is associated with Peters' anomaly, a congenital defect of the anterior chamber of the eye. Mutations in this gene may be associated with Loeys-Dietz syndrome. This gene encodes multiple isoforms that may undergo similar proteolytic processing. [provided by RefSeq, Aug 2016]

TGFB2 Gene-Disease associations (from GenCC):

• familial thoracic aortic aneurysm and aortic dissection

  Inheritance: AD Classification: DEFINITIVE, SUPPORTIVE Submitted by: Orphanet, ClinGen
• Loeys-Dietz syndrome 4

  Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: Ambry Genetics, Genomics England PanelApp, Labcorp Genetics (formerly Invitae), PanelApp Australia, G2P

ACMG classification

Our verdict: Uncertain_significance. The variant received 0 ACMG points.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_003238.6. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	TGFB2	NM_003238.6	MANE Select	c.759_760delTGinsAT	p.Asp254Tyr	missense	N/A	NP_003229.1
	TGFB2	NM_001135599.4		c.843_844delTGinsAT	p.Asp282Tyr	missense	N/A	NP_001129071.1
	TGFB2	NR_138148.2		n.2121-111_2121-110delTGinsAT		intron	N/A

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	TGFB2	ENST00000366930.9	TSL:1 MANE Select	c.759_760delTGinsAT	p.Asp254Tyr	missense	N/A	ENSP00000355897.4
	TGFB2	ENST00000366929.4	TSL:1	c.843_844delTGinsAT	p.Asp282Tyr	missense	N/A	ENSP00000355896.4
	TGFB2	ENST00000479322.1	TSL:3	n.243_244delTGinsAT		non_coding_transcript_exon	Exon 3 of 5

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

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Loeys-Dietz syndrome 4 Uncertain:1

Dec 17, 2017

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces aspartic acid with tyrosine at codon 254 of the TGFB2 protein (p.Asp254Tyr). The aspartic acid residue is highly conserved. This variant is not present in population databases (ExAC no frequency). This variant has not been reported in the literature in individuals with TGFB2-related disease. 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 disruptive, but these predictions have not been confirmed by published functional studies and their clinical significance is uncertain. 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.

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
PhyloP100		7.4

Splicing

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

Other links and lift over

dbSNP: rs1553303162; hg19: chr1-218609316;