chr19-55132935-C-T

Variant summary

Our verdict is Likely benign. The variant received -2 ACMG points: 0P and 2B. BP4_Moderate

The NM_003283.6(TNNT1):​c.817G>A​(p.Val273Ile) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000156 in 1,603,784 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

Frequency

Genomes: 𝑓 0.000020 ( 0 hom., cov: 31)
Exomes 𝑓: 0.000015 ( 0 hom. )

Consequence

TNNT1
NM_003283.6 missense

Scores

3
7
9

Clinical Significance

Uncertain significance criteria provided, single submitter U:1

Conservation

PhyloP100: 1.04

Publications

0 publications found
Variant links:
Genes affected
TNNT1 (HGNC:11948): (troponin T1, slow skeletal type) This gene encodes a protein that is a subunit of troponin, which is a regulatory complex located on the thin filament of the sarcomere. This complex regulates striated muscle contraction in response to fluctuations in intracellular calcium concentration. This complex is composed of three subunits: troponin C, which binds calcium, troponin T, which binds tropomyosin, and troponin I, which is an inhibitory subunit. This protein is the slow skeletal troponin T subunit. Mutations in this gene cause nemaline myopathy type 5, also known as Amish nemaline myopathy, a neuromuscular disorder characterized by muscle weakness and rod-shaped, or nemaline, inclusions in skeletal muscle fibers which affects infants, resulting in death due to respiratory insufficiency, usually in the second year. Multiple transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Jul 2008]
TNNT1 Gene-Disease associations (from GenCC):
  • nemaline myopathy 5
    Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Orphanet, Ambry Genetics, ClinGen, Labcorp Genetics (formerly Invitae)
  • nemaline myopathy
    Inheritance: AD Classification: LIMITED Submitted by: ClinGen
  • nemaline myopathy 5C, autosomal dominant
    Inheritance: AD Classification: LIMITED Submitted by: Ambry Genetics, Labcorp Genetics (formerly Invitae)

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Likely_benign. The variant received -2 ACMG points.

BP4
Computational evidence support a benign effect (MetaRNN=0.13298523).

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
TNNT1NM_003283.6 linkc.817G>A p.Val273Ile missense_variant Exon 14 of 14 ENST00000588981.6 NP_003274.3 P13805-1

Ensembl

Gene Transcript HGVSc HGVSp Effect Exon rank TSL MANE Protein Appris UniProt
TNNT1ENST00000588981.6 linkc.817G>A p.Val273Ile missense_variant Exon 14 of 14 1 NM_003283.6 ENSP00000467176.1 P13805-1

Frequencies

GnomAD3 genomes
AF:
0.0000197
AC:
3
AN:
152184
Hom.:
0
Cov.:
31
show subpopulations
Gnomad AFR
AF:
0.00
Gnomad AMI
AF:
0.00
Gnomad AMR
AF:
0.0000655
Gnomad ASJ
AF:
0.00
Gnomad EAS
AF:
0.00
Gnomad SAS
AF:
0.000207
Gnomad FIN
AF:
0.0000942
Gnomad MID
AF:
0.00
Gnomad NFE
AF:
0.00
Gnomad OTH
AF:
0.00
GnomAD2 exomes
AF:
0.0000173
AC:
4
AN:
230748
AF XY:
0.0000241
show subpopulations
Gnomad AFR exome
AF:
0.0000699
Gnomad AMR exome
AF:
0.00
Gnomad ASJ exome
AF:
0.00
Gnomad EAS exome
AF:
0.00
Gnomad FIN exome
AF:
0.0000507
Gnomad NFE exome
AF:
0.00000961
Gnomad OTH exome
AF:
0.00
GnomAD4 exome
AF:
0.0000152
AC:
22
AN:
1451600
Hom.:
0
Cov.:
31
AF XY:
0.0000236
AC XY:
17
AN XY:
720966
show subpopulations
African (AFR)
AF:
0.00
AC:
0
AN:
33406
American (AMR)
AF:
0.00
AC:
0
AN:
43126
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
25764
East Asian (EAS)
AF:
0.00
AC:
0
AN:
39424
South Asian (SAS)
AF:
0.0000835
AC:
7
AN:
83788
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
51938
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
5752
European-Non Finnish (NFE)
AF:
0.0000117
AC:
13
AN:
1108348
Other (OTH)
AF:
0.0000333
AC:
2
AN:
60054
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.493
Heterozygous variant carriers
0
3
6
8
11
14
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance

Age Distribution

Exome Het
Variant carriers
0
2
4
6
8
10
<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:
0.0000197
AC:
3
AN:
152184
Hom.:
0
Cov.:
31
AF XY:
0.0000404
AC XY:
3
AN XY:
74338
show subpopulations
African (AFR)
AF:
0.00
AC:
0
AN:
41442
American (AMR)
AF:
0.0000655
AC:
1
AN:
15270
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
3472
East Asian (EAS)
AF:
0.00
AC:
0
AN:
5190
South Asian (SAS)
AF:
0.000207
AC:
1
AN:
4824
European-Finnish (FIN)
AF:
0.0000942
AC:
1
AN:
10616
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
316
European-Non Finnish (NFE)
AF:
0.00
AC:
0
AN:
68048
Other (OTH)
AF:
0.00
AC:
0
AN:
2094
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.625
Heterozygous variant carriers
0
0
1
1
2
2
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance

Age Distribution

Genome Het
Variant carriers
0
2
4
6
8
10
<30
30-35
35-40
40-45
45-50
50-55
55-60
60-65
65-70
70-75
75-80
>80
Age
Alfa
AF:
0.00
Hom.:
0
Bravo
AF:
0.0000227
ExAC
AF:
0.0000165
AC:
2

ClinVar

Significance: Uncertain significance
Submissions summary: Uncertain:1
Revision: criteria provided, single submitter
LINK: link

Submissions by phenotype

Nemaline myopathy 5 Uncertain:1
Dec 21, 2021
Labcorp Genetics (formerly Invitae), Labcorp
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

This sequence change replaces valine, which is neutral and non-polar, with isoleucine, which is neutral and non-polar, at codon 273 of the TNNT1 protein (p.Val273Ile). 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. 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 tolerated. This variant has not been reported in the literature in individuals affected with TNNT1-related conditions. The frequency data for this variant in the population databases is considered unreliable, as metrics indicate poor data quality at this position in the gnomAD database. -

Computational scores

Source: dbNSFP v4.3

Name
Calibrated prediction
Score
Prediction
AlphaMissense
Benign
0.30
BayesDel_addAF
Uncertain
0.13
D
BayesDel_noAF
Uncertain
-0.050
CADD
Benign
20
DANN
Uncertain
1.0
DEOGEN2
Benign
0.28
.;.;.;T;T;.;.;.
Eigen
Benign
-0.33
Eigen_PC
Benign
-0.43
FATHMM_MKL
Benign
0.25
N
LIST_S2
Pathogenic
0.98
.;D;D;D;D;D;.;.
M_CAP
Pathogenic
0.36
D
MetaRNN
Benign
0.13
T;T;T;T;T;T;T;T
MetaSVM
Uncertain
0.57
D
MutationAssessor
Pathogenic
2.9
.;.;.;.;M;.;.;.
PhyloP100
1.0
PrimateAI
Uncertain
0.54
T
PROVEAN
Benign
-0.57
.;N;.;.;.;.;.;.
REVEL
Uncertain
0.43
Sift
Uncertain
0.027
.;D;.;.;.;.;.;.
Sift4G
Benign
0.071
T;T;T;D;T;T;T;T
Polyphen
0.40
B;B;B;.;P;.;.;.
Vest4
0.40
MutPred
0.27
.;.;.;.;Gain of catalytic residue at V273 (P = 0.0116);.;.;.;
MVP
0.92
MPC
0.80
ClinPred
0.45
T
GERP RS
1.7
RBP_binding_hub_radar
0.0
RBP_regulation_power_radar
1.1
Varity_R
0.089
gMVP
0.17
Mutation Taster
=88/12
polymorphism

Splicing

Name
Calibrated prediction
Score
Prediction
SpliceAI score (max)
0.030
Details are displayed if max score is > 0.2

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

Publications

Other links and lift over

dbSNP: rs774212109; hg19: chr19-55644303; API