Genetic Variant TNNT1:p.Lys278Lys (chr19-55132918-C-T) – ACMG Classification: Likely_benign (-5 pts)

Variant summary

Our verdict is Likely benign. The variant received -5 ACMG points: 0P and 5B. BP4_ModerateBP6_ModerateBP7

The NM_003283.6(TNNT1):c.834G>A(p.Lys278Lys) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000156 in 1,602,788 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 Likely benign (★).

Frequency

Genomes: 𝑓 0.0000066 ( 0 hom., cov: 31)

Exomes 𝑓: 0.000017 ( 0 hom. )

Consequence

TNNT1
NM_003283.6 synonymous

Scores

Clinical Significance

Likely benign criteria provided, single submitter B:1

Conservation

PhyloP100: 1.45

Publications

1 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)

TNNT1 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Likely_benign. The variant received -5 ACMG points.

BP4

Computational evidence support a benign effect (BayesDel_noAF=-0.33).

BP6

Variant 19-55132918-C-T is Benign according to our data. Variant chr19-55132918-C-T is described in ClinVar as [Likely_benign]. Clinvar id is 772350.Status of the report is criteria_provided_single_submitter, 1 stars.

BP7

Synonymous conserved (PhyloP=1.45 with no splicing effect.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TNNT1	NM_003283.6 link	c.834G>A	p.Lys278Lys	synonymous_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
TNNT1	ENST00000588981.6 link	c.834G>A	p.Lys278Lys	synonymous_variant	Exon 14 of 14	1	NM_003283.6	ENSP00000467176.1		P13805-1

Frequencies

GnomAD3 genomes

AF:

0.00000657

AC:

AN:

152200

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:

0.00

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.00000869

AC:

AN:

230072

AF XY:

0.0000161

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000193

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000165

AC:

AN:

1450588

Hom.:

Cov.:

AF XY:

0.0000208

AC XY:

AN XY:

720318

show subpopulations

African (AFR)

AF:

0.000329

AC:

AN:

33402

American (AMR)

AF:

0.00

AC:

AN:

42910

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

25724

East Asian (EAS)

AF:

0.00

AC:

AN:

39388

South Asian (SAS)

AF:

0.00

AC:

AN:

83646

European-Finnish (FIN)

AF:

0.00

AC:

AN:

51908

Middle Eastern (MID)

AF:

0.000348

AC:

AN:

5754

European-Non Finnish (NFE)

AF:

0.00000903

AC:

AN:

1107864

Other (OTH)

AF:

0.0000167

AC:

AN:

59992

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.440

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

GnomAD4 genome

AF:

0.00000657

AC:

AN:

152200

Hom.:

Cov.:

AF XY:

0.0000135

AC XY:

AN XY:

74346

show subpopulations

African (AFR)

AF:

0.0000241

AC:

AN:

41452

American (AMR)

AF:

0.00

AC:

AN:

15274

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3470

East Asian (EAS)

AF:

0.00

AC:

AN:

5198

South Asian (SAS)

AF:

0.00

AC:

AN:

4820

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10612

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

68052

Other (OTH)

AF:

0.00

AC:

AN:

2094

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.525

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Alfa

AF:

0.0000508

Hom.:

Bravo

AF:

0.00000756

ClinVar

Significance: Likely benign

Submissions summary: Benign:1

Revision: criteria provided, single submitter

LINK: link

Submissions by phenotype

Nemaline myopathy 5

Benign:1

Aug 20, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

BayesDel_noAF

Benign

-0.33

CADD

Benign

(source)

DANN

Benign

0.94

PhyloP100

1.4

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

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19-55132918-C-T

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