3-30688470-C-T

Position:

• chr3-30688470-C-T

Variant summary

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

The ENST00000295754.10(TGFBR2):​c.1483C>T​(p.Arg495*) variant causes a stop gained change. 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 Pathogenic (★★). Synonymous variant affecting the same amino acid position (i.e. R495R) has been classified as Likely benign.

• Frequency: Genomes: not found (cov: 33)
• Consequence: TGFBR2 ENST00000295754.10 stop_gained
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:8
• Conservation: PhyloP100: 4.46

Genes affected

TGFBR2 (HGNC:11773): (transforming growth factor beta receptor 2) The protein encoded by this gene is a transmembrane protein that has a protein kinase domain, forms a heterodimeric complex with TGF-beta receptor type-1, and binds TGF-beta. This receptor/ligand complex phosphorylates proteins, which then enter the nucleus and regulate the transcription of genes related to cell proliferation, cell cycle arrest, wound healing, immunosuppression, and tumorigenesis. Mutations in this gene have been associated with Marfan Syndrome, Loeys-Deitz Aortic Aneurysm Syndrome, and the development of various types of tumors. Alternatively spliced transcript variants encoding different isoforms have been characterized. [provided by RefSeq, Aug 2017]

TGFBR2 (HGNC:):

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 53 pathogenic variants in the truncated region.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 3-30688470-C-T is Pathogenic according to our data. Variant chr3-30688470-C-T is described in ClinVar as [Pathogenic]. Clinvar id is 12519.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr3-30688470-C-T is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
TGFBR2	NM_003242.6	c.1483C>T	p.Arg495*	stop_gained	6/7	ENST00000295754.10	NP_003233.4

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
TGFBR2	ENST00000295754.10	c.1483C>T	p.Arg495*	stop_gained	6/7	1	NM_003242.6	ENSP00000295754.5

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 33

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:8

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Familial thoracic aortic aneurysm and aortic dissection Pathogenic:2

Pathogenic, criteria provided, single submitter	clinical testing	Ambry Genetics	May 15, 2023	The p.R495* pathogenic mutation (also known as c.1483C>T), located in coding exon 6 of the TGFBR2 gene, results from a C to T substitution at nucleotide position 1483. This changes the amino acid from an arginine to a stop codon within coding exon 6. This alteration occurs at the 3' terminus of theTGFBR2 gene, is not expected to trigger nonsense-mediated mRNA decay, and only impacts the last 12.8% of the protein. However, premature stop codons are typically deleterious in nature and a significant portion of the protein is affected (Ambry internal data). This alteration has been reported in several individuals and families with a diagnosis of Loeys-Dietz syndrome (Loeys et al. N Engl J Med. 2006;355(8):788-98; Togashi et al. Intern Med. 2007;46(24):1995-2000; Yang et al. J Hum Genet. 2012;57:52-6). This variant is considered to be rare based on population cohorts in the Genome Aggregation Database (gnomAD). Based on the supporting evidence, this alteration is interpreted as a disease-causing mutation. -
Pathogenic, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Jan 11, 2024	This sequence change creates a premature translational stop signal (p.Arg495*) in the TGFBR2 gene. While this is not anticipated to result in nonsense mediated decay, it is expected to disrupt the last 73 amino acid(s) of the TGFBR2 protein. This variant is not present in population databases (gnomAD no frequency). This premature translational stop signal has been observed in individuals with Loeys-Dietz syndrome (PMID: 16928994, 17652900, 18084123, 22113417). ClinVar contains an entry for this variant (Variation ID: 12519). For these reasons, this variant has been classified as Pathogenic. -

Loeys-Dietz syndrome Pathogenic:2

Pathogenic, criteria provided, single submitter	clinical testing	Women's Health and Genetics/Laboratory Corporation of America, LabCorp	Jan 30, 2018	Variant summary: TGFBR2 c.1483C>T (p.Arg495X) results in a premature termination codon, predicted to cause a truncation of the encoded protein or absence of the protein due to nonsense mediated decay, which are commonly known mechanisms for disease. The variant was absent in 245910 control chromosomes. The c.1483C>T variant has been reported in the literature in multiple individuals affected with Loeys-Dietz Syndrome, including segregation with disease in a family (Togashi_2007). These data indicate that the variant is very likely to be associated with disease. At least one publication reports experimental evidence evaluating an impact on protein function, where an increase in intracellular collagen was observed in patient fibroblasts (Barnett_2011). Three clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014 without evidence for independent evaluation, each of which classified the variant as pathogenic. Based on the evidence outlined above, the variant was classified as pathogenic. -
Likely pathogenic, no assertion criteria provided	clinical testing	Blueprint Genetics	Jul 21, 2014	- -

not provided Pathogenic:2

Pathogenic, criteria provided, single submitter	clinical testing	Clinical Genetics Laboratory, Skane University Hospital Lund	Oct 31, 2022	- -
Pathogenic, criteria provided, single submitter	clinical testing	GeneDx	Jun 01, 2022	Not observed at significant frequency in large population cohorts (gnomAD); Published functional studies suggest a damaging effect by causing intracellular accumulation of collagen type I in patient-derived cultured fibroblasts (Barnett et al., 2011); Nonsense variant predicted to result in protein truncation in a gene for which loss-of-function is not a known mechanism of disease; This variant is associated with the following publications: (PMID: 25525159, 16928994, 18084123, 22113417, 17652900, 33059708, 34150014, 21267002, 26582918, 33084842) -

Malignant tumor of esophagus;C1860896:Colorectal cancer, hereditary nonpolyposis, type 6;C2674574:Loeys-Dietz syndrome 2 Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Fulgent Genetics, Fulgent Genetics

Oct 31, 2018

- -

Loeys-Dietz syndrome 2 Pathogenic:1

Pathogenic, no assertion criteria provided

literature only

OMIM

Aug 24, 2006

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.60	D
BayesDel_noAF	Pathogenic	0.49
CADD	Pathogenic	39
DANN	Uncertain	1.0
Eigen	Uncertain	0.46
Eigen_PC	Uncertain	0.30
FATHMM_MKL	Uncertain	0.87	D
MutationTaster	Benign	1.0	A;A
Vest4		0.90
GERP RS		3.5

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: rs104893819; hg19: chr3-30729962; COSMIC: COSV55443391;