17-39665994-G-C

Variant names:

• chr17-39665994-G-C
• rs147503632
• NM_003673.4:c.389G>C

Variant summary

Our verdict is Uncertain significance. The variant received 2 ACMG points: 2P and 0B. PM2

The NM_003673.4(TCAP):​c.389G>C​(p.Arg130Pro) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000685 in 1,460,140 control chromosomes in the GnomAD database, with no homozygous occurrence. 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. R130H) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: TCAP NM_003673.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 2.73
• Publications: 3 publications found

Genes affected

TCAP (HGNC:11610): (titin-cap) Sarcomere assembly is regulated by the muscle protein titin. Titin is a giant elastic protein with kinase activity that extends half the length of a sarcomere. It serves as a scaffold to which myofibrils and other muscle related proteins are attached. This gene encodes a protein found in striated and cardiac muscle that binds to the titin Z1-Z2 domains and is a substrate of titin kinase, interactions thought to be critical to sarcomere assembly. Mutations in this gene are associated with limb-girdle muscular dystrophy type 2G. [provided by RefSeq, Jul 2008]

TCAP Gene-Disease associations (from GenCC):

• autosomal recessive limb-girdle muscular dystrophy

  Inheritance: AR Classification: DEFINITIVE Submitted by: ClinGen
• hypertrophic cardiomyopathy 25

  Inheritance: AD Classification: STRONG, MODERATE, LIMITED Submitted by: Ambry Genetics, PanelApp Australia, Labcorp Genetics (formerly Invitae)
• autosomal recessive limb-girdle muscular dystrophy type 2G

  Inheritance: AR Classification: STRONG, SUPPORTIVE Submitted by: Orphanet, Ambry Genetics, Labcorp Genetics (formerly Invitae)
• familial isolated dilated cardiomyopathy

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• dilated cardiomyopathy

  Inheritance: AD Classification: LIMITED Submitted by: ClinGen
• hypertrophic cardiomyopathy

  Inheritance: AD Classification: NO_KNOWN Submitted by: ClinGen

ACMG classification

Our verdict: Uncertain_significance. The variant received 2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TCAP	NM_003673.4	c.389G>C	p.Arg130Pro	missense_variant	Exon 2 of 2	ENST00000309889.3	NP_003664.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TCAP	ENST00000309889.3	c.389G>C	p.Arg130Pro	missense_variant	Exon 2 of 2	1	NM_003673.4	ENSP00000312624.2
TCAP	ENST00000578283.1	c.317G>C	p.Arg106Pro	missense_variant	Exon 3 of 3	5		ENSP00000462787.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.85e-7 AC: 1 AN: 1460140 Hom.: 0 Cov.: 30 AF XY: 0.00000138 AC XY: 1 AN XY: 726414

⚠️ 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: 33474

American (AMR) AF: 0.00 AC: 0 AN: 44718

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26134

East Asian (EAS) AF: 0.00 AC: 0 AN: 39696

South Asian (SAS) AF: 0.00 AC: 0 AN: 86252

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 51784

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

European-Non Finnish (NFE) AF: 8.99e-7 AC: 1 AN: 1111938

Other (OTH) AF: 0.00 AC: 0 AN: 60376

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0), which strongly suggests a high chance of mosaicism in these individuals.

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Primary familial hypertrophic cardiomyopathy;C4225408:Hypertrophic cardiomyopathy 25 Uncertain:1

Jul 25, 2017

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces arginine with proline at codon 130 of the TCAP protein (p.Arg130Pro). The arginine residue is moderately conserved and there is a moderate physicochemical difference between arginine and proline. This variant is not present in population databases (ExAC no frequency). This variant has not been reported in the literature in individuals with TCAP-related disease. Algorithms developed to predict the effect of missense changes on protein structure and function (SIFT, PolyPhen-2, Align-GVGD) all suggest that this variant is likely to be disruptive, but these predictions have not been confirmed by published functional studies and their clinical significance is uncertain. In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance.

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Uncertain	0.44
BayesDel_addAF	Pathogenic	0.26	D
BayesDel_noAF	Pathogenic	0.14
CADD	Uncertain	26
DANN	Benign	0.93
DEOGEN2	Pathogenic	0.80	D;.
Eigen	Uncertain	0.46
Eigen_PC	Uncertain	0.52
FATHMM_MKL	Uncertain	0.84	D
LIST_S2	Benign	0.83	T;T
M_CAP	Uncertain	0.14	D
MetaRNN	Uncertain	0.65	D;D
MetaSVM	Uncertain	0.52	D
MutationAssessor	Benign	1.9	M;.
PhyloP100		2.7
PrimateAI	Uncertain	0.51	T
PROVEAN	Pathogenic	-4.7	D;.
REVEL	Uncertain	0.62
Sift	Uncertain	0.0070	D;.
Sift4G	Uncertain	0.013	D;D
Vest4		0.40
ClinPred		0.98	D
GERP RS		5.7
Varity_R		0.93
gMVP		0.94
Mutation Taster		=49/51	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: rs147503632; hg19: chr17-37822247;