chr19-55132964-T-C

Variant names:

• chr19-55132964-T-C
• NM_003283.6:c.792-4A>G

Variant summary

Our verdict is Likely benign. The variant received -4 ACMG points: 2P and 6B. PM2 BP4_Strong BP6_Moderate

The NM_003283.6(TNNT1):​c.792-4A>G variant causes a splice region, intron 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. 3/3 splice prediction tools predict no significant impact on normal splicing. Variant has been reported in ClinVar as Likely benign (★).

• Frequency:
  • Genomes: not found (cov: 31)
  • Exomes 𝑓: 0.0 (0 hom.)
  • Failed GnomAD Quality Control
• Consequence: TNNT1 NM_003283.6 splice_region, intron
• Scores: Splicing: ADA: 0.00006674
• Clinical Significance: Likely benign criteria provided, single submitter B:1
• Conservation: PhyloP100: -2.17
• Publications: 0 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: Orphanet, Ambry Genetics, ClinGen, Labcorp Genetics (formerly Invitae)
• nemaline myopathy

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

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

ACMG classification

Our verdict: Likely_benign. The variant received -4 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.7).
• BP6: Variant 19-55132964-T-C is Benign according to our data. Variant chr19-55132964-T-C is described in ClinVar as [Likely_benign]. Clinvar id is 3655380.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TNNT1	NM_003283.6	c.792-4A>G		splice_region_variant, intron_variant	Intron 13 of 13	ENST00000588981.6	NP_003274.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TNNT1	ENST00000588981.6	c.792-4A>G		splice_region_variant, intron_variant	Intron 13 of 13	1	NM_003283.6	ENSP00000467176.1

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD4 exome Data not reliable, filtered out with message: AC0 AF: 0.00 AC: 0 AN: 1447956 Hom.: 0 Cov.: 31 AF XY: 0.00 AC XY: 0 AN XY: 718838

African (AFR) AF: 0.00 AC: 0 AN: 33390

American (AMR) AF: 0.00 AC: 0 AN: 42182

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 25712

East Asian (EAS) AF: 0.00 AC: 0 AN: 39336

South Asian (SAS) AF: 0.00 AC: 0 AN: 83442

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 51560

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5750

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1106654

Other (OTH) AF: 0.00 AC: 0 AN: 59930

GnomAD4 genome Cov.: 31

ClinVar

Significance: Likely benign

Submissions summary: Benign:1

Revision: criteria provided, single submitter

Submissions by phenotype

Nemaline myopathy 5 Benign:1

Jun 03, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

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Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.70
CADD	Benign	3.7
DANN	Benign	0.84
PhyloP100		-2.2

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Benign	0.000067
dbscSNV1_RF	Benign	0.016
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

hg19: chr19-55644332;