11-1922883-C-G

Variant names:

• chr11-1922883-C-G
• rs750777064
• NM_006757.4:c.9C>G

Variant summary

Our verdict is Uncertain significance. The variant received 1 ACMG points: 2P and 1B. PM2 BP4

The NM_006757.4(TNNT3):​c.9C>G​(p.Asp3Glu) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. D3V) has been classified as Benign.

• Frequency: Genomes: not found (cov: 32)
• Consequence: TNNT3 NM_006757.4 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 2.28
• Publications: 0 publications found

Genes affected

TNNT3 (HGNC:11950): (troponin T3, fast skeletal type) The binding of Ca(2+) to the trimeric troponin complex initiates the process of muscle contraction. Increased Ca(2+) concentrations produce a conformational change in the troponin complex that is transmitted to tropomyosin dimers situated along actin filaments. The altered conformation permits increased interaction between a myosin head and an actin filament which, ultimately, produces a muscle contraction. The troponin complex has protein subunits C, I, and T. Subunit C binds Ca(2+) and subunit I binds to actin and inhibits actin-myosin interaction. Subunit T binds the troponin complex to the tropomyosin complex and is also required for Ca(2+)-mediated activation of actomyosin ATPase activity. There are 3 different troponin T genes that encode tissue-specific isoforms of subunit T for fast skeletal-, slow skeletal-, and cardiac-muscle. This gene encodes fast skeletal troponin T protein; also known as troponin T type 3. Alternative splicing results in multiple transcript variants encoding additional distinct troponin T type 3 isoforms. A developmentally regulated switch between fetal/neonatal and adult troponin T type 3 isoforms occurs. Additional splice variants have been described but their biological validity has not been established. Mutations in this gene may cause distal arthrogryposis multiplex congenita type 2B (DA2B). [provided by RefSeq, Oct 2009]

TNNT3 Gene-Disease associations (from GenCC):

• arthrogryposis, distal, type 2B2

  Inheritance: AD Classification: STRONG, MODERATE Submitted by: Ambry Genetics, PanelApp Australia
• distal arthrogryposis type 2B1

  Inheritance: AD Classification: STRONG Submitted by: Labcorp Genetics (formerly Invitae)
• congenital myopathy

  Inheritance: AR Classification: STRONG Submitted by: G2P
• nemaline myopathy

  Inheritance: AR Classification: MODERATE, LIMITED Submitted by: ClinGen, Ambry Genetics
• digitotalar dysmorphism

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• Sheldon-hall syndrome

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

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

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.3570012).

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_006757.4. 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
	TNNT3	NM_006757.4	MANE Select	c.9C>G	p.Asp3Glu	missense	Exon 2 of 16	NP_006748.1	P45378-2
	TNNT3	NM_001367846.1		c.9C>G	p.Asp3Glu	missense	Exon 2 of 18	NP_001354775.1	P45378-1
	TNNT3	NM_001363561.2		c.9C>G	p.Asp3Glu	missense	Exon 2 of 17	NP_001350490.1	P45378-3

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	TNNT3	ENST00000278317.11	TSL:5 MANE Select	c.9C>G	p.Asp3Glu	missense	Exon 2 of 16	ENSP00000278317.6	P45378-2
	TNNT3	ENST00000381589.7	TSL:1	c.9C>G	p.Asp3Glu	missense	Exon 2 of 16	ENSP00000371001.3	P45378-6
	TNNT3	ENST00000381579.7	TSL:1	c.9C>G	p.Asp3Glu	missense	Exon 2 of 15	ENSP00000370991.3	P45378-4

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 38

GnomAD4 genome Cov.: 32

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.11
BayesDel_addAF	Pathogenic	0.19	D
BayesDel_noAF	Uncertain	0.030
CADD	Benign	22
DANN	Uncertain	0.99
DEOGEN2	Benign	0.26	T
Eigen	Uncertain	0.28
Eigen_PC	Uncertain	0.24
FATHMM_MKL	Uncertain	0.81	D
LIST_S2	Benign	0.66	T
M_CAP	Pathogenic	0.94	D
MetaRNN	Benign	0.36	T
MetaSVM	Pathogenic	1.0	D
PhyloP100		2.3
PrimateAI	Uncertain	0.77	T
PROVEAN	Benign	-0.74	N
REVEL	Benign	0.087
Sift	Benign	0.24	T
Sift4G	Benign	0.59	T
Polyphen		0.89	P
Vest4		0.43
MutPred		0.20		Loss of helix (P = 0.5774)
MVP		0.99
MPC		0.31
ClinPred		0.95	D
GERP RS		3.2
PromoterAI		-0.0030	Neutral
Varity_R		0.077
gMVP		0.46
Mutation Taster		=73/27	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

Other links and lift over

dbSNP: rs750777064; hg19: chr11-1944113;