chr1-201413063-A-G

Variant names:

• chr1-201413063-A-G
• rs1662665450
• NM_003281.4:c.248T>C

Variant summary

Our verdict is Uncertain significance. The variant received 4 ACMG points: 4P and 0B. PM2 PP3_Moderate

The NM_003281.4(TNNI1):​c.248T>C​(p.Ile83Thr) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,792 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: TNNI1 NM_003281.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 7.48
• Publications: 0 publications found

Genes affected

TNNI1 (HGNC:11945): (troponin I1, slow skeletal type) Troponin proteins associate with tropomyosin and regulate the calcium sensitivity of the myofibril contractile apparatus of striated muscles. Troponin I (TnI), along with troponin T (TnT) and troponin C (TnC), is one of 3 subunits that form the troponin complex of the thin filaments of striated muscle. TnI is the inhibitory subunit; blocking actin-myosin interactions and thereby mediating striated muscle relaxation. The TnI subfamily contains three genes: TnI-skeletal-fast-twitch, TnI-skeletal-slow-twitch, and TnI-cardiac. The TnI-fast and TnI-slow genes are expressed in fast-twitch and slow-twitch skeletal muscle fibers, respectively, while the TnI-cardiac gene is expressed exclusively in cardiac muscle tissue. This gene encodes the Troponin-I-skeletal-slow-twitch protein. This gene is expressed in cardiac and skeletal muscle during early development but is restricted to slow-twitch skeletal muscle fibers in adults. The encoded protein prevents muscle contraction by inhibiting calcium-mediated conformational changes in actin-myosin complexes. [provided by RefSeq, Jul 2008]

ACMG classification

Our verdict: Uncertain_significance. The variant received 4 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.86

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TNNI1	NM_003281.4	c.248T>C	p.Ile83Thr	missense_variant	Exon 6 of 9	ENST00000361379.9	NP_003272.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TNNI1	ENST00000361379.9	c.248T>C	p.Ile83Thr	missense_variant	Exon 6 of 9	5	NM_003281.4	ENSP00000354488.4

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461792 Hom.: 0 Cov.: 31 AF XY: 0.00000138 AC XY: 1 AN XY: 727188

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

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

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

Ashkenazi Jewish (ASJ) AF: 0.0000383 AC: 1 AN: 26132

East Asian (EAS) AF: 0.00 AC: 0 AN: 39698

South Asian (SAS) AF: 0.00 AC: 0 AN: 86254

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53402

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

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1111946

Other (OTH) AF: 0.00 AC: 0 AN: 60388

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0.000000), which strongly suggests a high chance of mosaicism in these individuals.

GnomAD4 genome Cov.: 33

Alfa AF: 0.00 Hom.: 0

Bravo AF: 0.00000378

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not specified Uncertain:1

Mar 29, 2022

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The c.248T>C (p.I83T) alteration is located in exon 6 (coding exon 5) of the TNNI1 gene. This alteration results from a T to C substitution at nucleotide position 248, causing the isoleucine (I) at amino acid position 83 to be replaced by a threonine (T). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.18
BayesDel_addAF	Pathogenic	0.45	D
BayesDel_noAF	Pathogenic	0.40
CADD	Uncertain	24
DANN	Uncertain	1.0
DEOGEN2	Benign	0.38	T;D;D;.;D;D;.
Eigen	Uncertain	0.63
Eigen_PC	Uncertain	0.56
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.88	D;.;.;D;D;D;D
M_CAP	Pathogenic	0.38	D
MetaRNN	Pathogenic	0.86	D;D;D;D;D;D;D
MetaSVM	Pathogenic	0.96	D
MutationAssessor	Uncertain	2.1	.;M;M;.;M;.;.
PhyloP100		7.5
PrimateAI	Uncertain	0.71	T
PROVEAN	Benign	-2.2	.;N;N;N;N;N;N
REVEL	Pathogenic	0.78
Sift	Benign	0.17	.;T;T;T;T;T;T
Sift4G	Benign	0.070	T;T;T;T;T;T;T
Polyphen		1.0	.;D;D;.;D;.;.
Vest4		0.64
MutPred		0.39		Gain of disorder (P = 0.0151);Gain of disorder (P = 0.0151);Gain of disorder (P = 0.0151);Gain of disorder (P = 0.0151);Gain of disorder (P = 0.0151);.;Gain of disorder (P = 0.0151);
MVP		0.99
MPC		1.9
ClinPred		0.97	D
GERP RS		5.1
Varity_R		0.19
gMVP		0.63
Mutation Taster		=34/66	disease causing

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

Other links and lift over

dbSNP: rs1662665450; hg19: chr1-201382191;