rs377276702

Variant names:

• chr19-55133890-T-C
• rs377276702
• NM_003283.6:c.788A>G
• TNNT1 p.Lys263Arg

Variant summary

Our verdict is Uncertain significance. The variant received 1 ACMG points: 1P and 0B. PP3

The NM_003283.6(TNNT1):​c.788A>G​(p.Lys263Arg) variant causes a missense change. The variant allele was found at a frequency of 0.0000149 in 1,613,692 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: 𝑓 0.0000066 (0 hom., cov: 30)
  • Exomes 𝑓: 0.000016 (0 hom.)
• Consequence: TNNT1 NM_003283.6 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 6.96
• Publications: 7 publications found

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: Labcorp Genetics (formerly Invitae), ClinGen, Ambry Genetics, Orphanet
• nemaline myopathy 5B, autosomal recessive, childhood-onset

  Inheritance: AR Classification: STRONG Submitted by: PanelApp Australia
• nemaline myopathy

  Inheritance: AD Classification: LIMITED Submitted by: ClinGen, PanelApp Australia
• nemaline myopathy 5C, autosomal dominant

  Inheritance: AD Classification: LIMITED Submitted by: Labcorp Genetics (formerly Invitae), Ambry Genetics

ACMG classification

Our verdict: Uncertain_significance. The variant received 1 ACMG points.

• PP3: Splicing predictors support a deleterious effect. Scorers claiming Pathogenic: max_spliceai. No scorers claiming Uncertain. No scorers claiming Benign.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_003283.6. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	TNNT1	NM_003283.6	MANE Select	c.788A>G	p.Lys263Arg	missense	Exon 13 of 14	NP_003274.3
	TNNT1	NM_001126132.3		c.740A>G	p.Lys247Arg	missense	Exon 13 of 14	NP_001119604.1	P13805-3
	TNNT1	NM_001126133.3		c.707A>G	p.Lys236Arg	missense	Exon 12 of 13	NP_001119605.1	P13805-2

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	TNNT1	ENST00000588981.6	TSL:1 MANE Select	c.788A>G	p.Lys263Arg	missense	Exon 13 of 14	ENSP00000467176.1	P13805-1
	TNNT1	ENST00000291901.12	TSL:1	c.740A>G	p.Lys247Arg	missense	Exon 13 of 14	ENSP00000291901.8	P13805-3
	TNNT1	ENST00000356783.9	TSL:1	c.707A>G	p.Lys236Arg	missense	Exon 12 of 13	ENSP00000349233.4	P13805-2

Frequencies

GnomAD3 genomes AF: 0.00000658 AC: 1 AN: 152042 Hom.: 0 Cov.: 30

Gnomad AFR AF: 0.0000242

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: 0.00000797 AC: 2 AN: 250918 AF XY: 0.00

Gnomad AFR exome AF: 0.0000616

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: 0.00000883

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.0000157 AC: 23 AN: 1461650 Hom.: 0 Cov.: 33 AF XY: 0.0000138 AC XY: 10 AN XY: 727100

African (AFR) AF: 0.00 AC: 0 AN: 33480

American (AMR) AF: 0.00 AC: 0 AN: 44724

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26136

East Asian (EAS) AF: 0.00 AC: 0 AN: 39700

South Asian (SAS) AF: 0.00 AC: 0 AN: 86258

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53188

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 0.0000207 AC: 23 AN: 1112004

Other (OTH) AF: 0.00 AC: 0 AN: 60392

GnomAD4 genome AF: 0.00000658 AC: 1 AN: 152042 Hom.: 0 Cov.: 30 AF XY: 0.00 AC XY: 0 AN XY: 74260

⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5.

African (AFR) AF: 0.0000242 AC: 1 AN: 41398

American (AMR) AF: 0.00 AC: 0 AN: 15260

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3470

East Asian (EAS) AF: 0.00 AC: 0 AN: 5172

South Asian (SAS) AF: 0.00 AC: 0 AN: 4822

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10602

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 316

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 68000

Other (OTH) AF: 0.00 AC: 0 AN: 2090

⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5. (p-value = 0), which strongly suggests a high chance of mosaicism in these individuals.

Alfa AF: 0.0000712 Hom.: 0

Bravo AF: 0.00000756

ClinVar

ClinVar submissions

Significance: Uncertain significance

Revision: criteria provided, single submitter

Pathogenic	VUS	Benign	Condition
-	1	-	Nemaline myopathy 5 (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.25
BayesDel_addAF	Benign	-0.051	T
BayesDel_noAF	Benign	-0.13
CADD	Pathogenic	35
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.68	D
Eigen	Uncertain	0.39
Eigen_PC	Uncertain	0.33
FATHMM_MKL	Uncertain	0.97	D
LIST_S2	Benign	0.82	T
M_CAP	Pathogenic	0.42	D
MetaRNN	Uncertain	0.69	D
MetaSVM	Uncertain	0.61	D
MutationAssessor	Benign	1.8	L
PhyloP100		7.0
PrimateAI	Pathogenic	0.86	D
PROVEAN	Benign	-2.1	N
REVEL	Uncertain	0.54
Sift	Benign	0.043	D
Sift4G	Benign	0.14	T
Varity_R		0.22
gMVP		0.27
Mutation Taster		=86/14	polymorphism

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.61		Details are displayed if max score is > 0.2
DS_DG_spliceai		0.61		Position offset: 0

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

MaxEntScan Visualizer can be used to analyze the impact of this mutation on the neighboring sequence.

Other links and lift over

dbSNP: rs377276702;

hg19: chr19-55645258;