rs377052919

Variant names:

Variant summary

Our verdict is Uncertain significance. The variant received 0 ACMG points: 3P and 3B. PM1PP2BP4_ModerateBS2_Supporting

The NM_000371.4(TTR):c.68C>T(p.Thr23Met) variant causes a missense, splice region change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000254 in 1,613,956 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 19/24 in silico tools predict a benign outcome for this variant. 3/3 splice prediction tools predict no significant impact on normal splicing. Variant has been reported in ClinVar as Uncertain significance (★★). Synonymous variant affecting the same amino acid position (i.e. T23T) has been classified as Likely benign.

Frequency

Genomes: 𝑓 0.000013 ( 0 hom., cov: 32)

Exomes 𝑓: 0.000027 ( 0 hom. )

Consequence

TTR
NM_000371.4 missense, splice_region

Scores

Splicing: ADA: 0.0006935

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:6

Conservation

PhyloP100: -0.544

Publications

2 publications found

Variant links:

Genes affected

TTR (HGNC:12405): (transthyretin) This gene encodes one of the three prealbumins, which include alpha-1-antitrypsin, transthyretin and orosomucoid. The encoded protein, transthyretin, is a homo-tetrameric carrier protein, which transports thyroid hormones in the plasma and cerebrospinal fluid. It is also involved in the transport of retinol (vitamin A) in the plasma by associating with retinol-binding protein. The protein may also be involved in other intracellular processes including proteolysis, nerve regeneration, autophagy and glucose homeostasis. Mutations in this gene are associated with amyloid deposition, predominantly affecting peripheral nerves or the heart, while a small percentage of the gene mutations are non-amyloidogenic. The mutations are implicated in the etiology of several diseases, including amyloidotic polyneuropathy, euthyroid hyperthyroxinaemia, amyloidotic vitreous opacities, cardiomyopathy, oculoleptomeningeal amyloidosis, meningocerebrovascular amyloidosis and carpal tunnel syndrome. [provided by RefSeq, Aug 2017]

TTR Gene-Disease associations (from GenCC):

amyloidosis, hereditary systemic 1
Inheritance: AD Classification: DEFINITIVE Submitted by: G2P
familial amyloid neuropathy
Inheritance: AD Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Orphanet, Ambry Genetics, Labcorp Genetics (formerly Invitae)
hereditary ATTR amyloidosis
Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
heart conduction disease
Inheritance: AD Classification: STRONG Submitted by: Genomics England PanelApp
ATTRV122I amyloidosis
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet

TTR links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

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

PM1

In a hotspot region, there are 3 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 1 benign, 11 uncertain in NM_000371.4

PP2

Missense variant in the gene, where a lot of missense mutations are associated with disease in ClinVar. The gene has 108 curated pathogenic missense variants (we use a threshold of 10). The gene has 3 curated benign missense variants. Gene score misZ: 1.0149 (below the threshold of 3.09). Trascript score misZ: 1.5458 (below the threshold of 3.09). GenCC associations: The gene is linked to familial amyloid neuropathy, amyloidosis, hereditary systemic 1, ATTRV122I amyloidosis, hereditary ATTR amyloidosis, heart conduction disease.

BP4

Computational evidence support a benign effect (MetaRNN=0.09614962).

BS2

High AC in GnomAdExome4 at 39 AD gene. Variant has AC lower than other variant known as pathogenic in the gene, so the strength is limited to Supporting.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TTR	NM_000371.4 link	c.68C>T	p.Thr23Met	missense_variant, splice_region_variant	Exon 1 of 4	ENST00000237014.8	NP_000362.1	P02766E9KL36

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TTR	ENST00000237014.8 link	c.68C>T	p.Thr23Met	missense_variant, splice_region_variant	Exon 1 of 4	1	NM_000371.4	ENSP00000237014.4		P02766

Frequencies

GnomAD3 genomes

AF:

0.0000131

AC:

AN:

152192

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000241

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.0000147

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.0000239

AC:

AN:

251332

AF XY:

0.0000221

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.0000289

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000440

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000267

AC:

AN:

1461764

Hom.:

Cov.:

AF XY:

0.0000289

AC XY:

AN XY:

727190

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33472

American (AMR)

AF:

0.0000224

AC:

AN:

44714

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26136

East Asian (EAS)

AF:

0.0000252

AC:

AN:

39696

South Asian (SAS)

AF:

0.00

AC:

AN:

86256

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53412

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

0.0000306

AC:

AN:

1111932

Other (OTH)

AF:

0.0000497

AC:

AN:

60378

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.465

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

GnomAD4 genome

AF:

0.0000131

AC:

AN:

152192

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

74362

show subpopulations

African (AFR)

AF:

0.0000241

AC:

AN:

41448

American (AMR)

AF:

0.00

AC:

AN:

15284

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3470

East Asian (EAS)

AF:

0.00

AC:

AN:

5200

South Asian (SAS)

AF:

0.00

AC:

AN:

4826

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10612

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.0000147

AC:

AN:

68034

Other (OTH)

AF:

0.00

AC:

AN:

2092

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.500

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Alfa

AF:

0.0000170

Hom.:

Bravo

AF:

0.0000151

ESP6500AA

AF:

0.000227

AC:

ESP6500EA

AF:

0.00

AC:

ExAC

AF:

0.0000412

AC:

Asia WGS

AF:

0.000866

AC:

AN:

3478

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:6

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Cardiovascular phenotype

Uncertain:2

Apr 18, 2022

Ambry Genetics

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The c.68C>T (p.T23M) alteration is located in exon 1 (coding exon 1) of the TTR gene. This alteration results from a C to T substitution at nucleotide position 68, causing the threonine (T) at amino acid position 23 to be replaced by a methionine (M). The alteration is rare in population databases: _x000D_ _x000D_ Based on data from the Genome Aggregation Database (gnomAD), the c.68C>T alteration was observed in 0.002% (6/251,332) of total alleles studied. The altered amino acid is not conserved throughout evolution:_x000D_ _x000D_ The p.T23 amino acid is not conserved in available vertebrate species. The alteration is predicted benign by in silico models:_x000D_ _x000D_ The p.T23M alteration is predicted to be benign by Polyphen and tolerated by SIFT in silico analyses. Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

Apr 09, 2025

Molecular Diagnostic Laboratory for Inherited Cardiovascular Disease, Montreal Heart Institute

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

PM2, PP2, BP4 -

not specified

Uncertain:1

Jul 31, 2012

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Variant classified as Uncertain Significance - Favor Benign. The Thr23Met varian t in TTR has not been reported in the literature nor previously identified by ou r laboratory. Threonine (Thr) at position 23 is not conserved in evolution, sugg esting that a change at this position may be tolerated. Computational analyses ( biochemical amino acid properties, AlignGVGD, PolyPhen2, and SIFT) also suggest that this variant may not impact the protein. This variant is located in the las t three bases of the exon, which is part of the 5' splice region, but computatio nal tools do not predict altered splicing (the accuracy of these tools is unknow n). The lack of amino acid conservation suggests that the Tyr535His variant may be benign, but additional studies are needed to establish this with confidence. -

Hyperthyroxinemia, dystransthyretinemic;C2751492:Amyloidosis, hereditary systemic 1;C5779776:Carpal tunnel syndrome 1

Uncertain:1

Jun 04, 2024

Fulgent Genetics, Fulgent Genetics

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

not provided

Uncertain:1

Dec 17, 2019

GeneDx

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Has not been previously published in association with TTR-related disorders to our knowledge; Reported in ClinVar as a variant of uncertain significance (ClinVar Variant ID# 663602; Landrum et al., 2016); In silico analysis, which includes protein predictors and evolutionary conservation, supports that this variant does not alter protein structure/function; This variant is associated with the following publications: (PMID: 30683924) -

Amyloidosis, hereditary systemic 1

Uncertain:1

Dec 11, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change replaces threonine, which is neutral and polar, with methionine, which is neutral and non-polar, at codon 23 of the TTR protein (p.Thr23Met). This variant is present in population databases (rs377052919, gnomAD 0.007%). This variant has not been reported in the literature in individuals affected with TTR-related conditions. ClinVar contains an entry for this variant (Variation ID: 43456). An algorithm developed to predict the effect of missense changes on protein structure and function (PolyPhen-2) suggests that this variant¬†is likely to be tolerated. 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 v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.10

BayesDel_addAF

Benign

-0.18

BayesDel_noAF

Benign

-0.31

CADD

Benign

1.3

(source)

DANN

Benign

0.67

DEOGEN2

Benign

0.18

T;T;T;.

Eigen

Benign

-1.5

Eigen_PC

Benign

-1.6

FATHMM_MKL

Benign

0.025

LIST_S2

Benign

0.26

.;T;T;T

M_CAP

Benign

0.048

MetaRNN

Benign

0.096

T;T;T;T

MetaSVM

Uncertain

-0.23

MutationAssessor

Benign

0.55

N;N;.;.

PhyloP100

-0.54

PrimateAI

Benign

0.27

PROVEAN

Benign

0.44

.;N;.;.

REVEL

Benign

0.23

Sift

Benign

0.24

.;T;.;.

Sift4G

Benign

0.29

.;T;T;T

Polyphen

0.020

B;B;.;.

Vest4

0.092, 0.14, 0.12

MVP

0.62

MPC

0.48

ClinPred

0.044

GERP RS

-7.9

PromoterAI

-0.10

Neutral

(source)

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.3

Varity_R

0.057

gMVP

0.66

Mutation Taster

=86/14

polymorphism

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

dbscSNV1_ADA

Benign

0.00069

dbscSNV1_RF

Benign

0.034

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

You must be logged in to view publications. This limit was set because tens of millions (!) of queries from AI bots are generated daily.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over