rs727504869

Positions:

• chr1-201366843-C-G
• chr1-201366843-C-T

Variant summary

Our verdict is Likely pathogenic. Variant got 6 ACMG points: 6P and 0B. PM1 PM2 PM5

The NM_001276345.2(TNNT2):​c.228G>C​(p.Lys76Asn) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Uncertain significance (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. K76Q) has been classified as Pathogenic.

• Frequency: Genomes: not found (cov: 32)
• Consequence: TNNT2 NM_001276345.2 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 3.32

Genes affected

TNNT2 (HGNC:11949): (troponin T2, cardiac type) This gene encodes the cardiac isoform of troponin T. The encoded protein is the tropomyosin-binding subunit of the troponin complex, which is located on the thin filament of striated muscles and regulates muscle contraction in response to alterations in intracellular calcium ion concentration. Mutations in this gene have been associated with familial hypertrophic cardiomyopathy as well as with dilated cardiomyopathy. [provided by RefSeq, May 2022]

ACMG classification

Verdict is Likely_pathogenic. Variant got 6 ACMG points.

• PM1: In a chain Troponin T, cardiac muscle (size 296) in uniprot entity TNNT2_HUMAN there are 88 pathogenic changes around while only 9 benign (91%) in NM_001276345.2
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr1-201366845-T-G is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
TNNT2	NM_001276345.2	c.228G>C	p.Lys76Asn	missense_variant	8/17	ENST00000656932.1	NP_001263274.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
TNNT2	ENST00000656932.1	c.228G>C	p.Lys76Asn	missense_variant	8/17		NM_001276345.2	ENSP00000499593	A2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 34

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not specified Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

Nov 21, 2013

The Lys66Asn variant in TNNT2 has not been previously reported in individuals wi th cardiomyopathy or in large population studies. Computational analyses (bioche mical amino acid properties, conservation, AlignGVGD, PolyPhen2, and SIFT) do no t provide strong support for or against an impact to the protein. Additional inf ormation is needed to fully assess the clinical significance of the Lys66Asn var iant. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.82
CardioboostCm	Uncertain	0.36
BayesDel_addAF	Pathogenic	0.17	D
BayesDel_noAF	Uncertain	0.010
CADD	Pathogenic	35
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.88	.;.;.;.;D;.;.;.;.;.;T;.;.;D
Eigen	Uncertain	0.57
Eigen_PC	Uncertain	0.54
FATHMM_MKL	Uncertain	0.93	D
LIST_S2	Uncertain	0.97	.;D;D;D;D;D;D;.;.;D;.;.;D;.
M_CAP	Pathogenic	0.72	D
MetaRNN	Uncertain	0.62	D;D;D;D;D;D;D;D;D;D;D;D;D;D
MetaSVM	Pathogenic	1.0	D
MutationAssessor	Uncertain	2.7	.;.;.;.;M;.;.;.;.;.;.;.;.;.
MutationTaster	Benign	1.0	D;D;D;D;D;D;D;D;D;D
PrimateAI	Uncertain	0.57	T
PROVEAN	Uncertain	-3.3	D;D;.;.;.;.;.;.;D;D;D;D;D;D
REVEL	Uncertain	0.62
Sift	Uncertain	0.0020	D;D;.;.;.;.;.;.;D;D;D;D;D;D
Sift4G	Uncertain	0.025	D;D;D;D;D;D;D;D;D;D;.;D;T;.
Polyphen		1.0, 1.0	.;.;.;.;D;.;.;.;.;.;D;.;.;.
Vest4		0.57
MutPred		0.41		.;.;.;.;Loss of methylation at K76 (P = 6e-04);.;.;.;.;.;.;Loss of methylation at K76 (P = 6e-04);.;.;
MVP		0.97
MPC		1.4
ClinPred		0.99	D
GERP RS		4.7
Varity_R		0.34
gMVP		0.67

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

LitVar

Other links and lift over

dbSNP: rs727504869; hg19: chr1-201335971;