Titin Variants in Dilated Cardiomyopathy

TTN Transcript / Exon Structure & Truncating Variants in Cardiomyopathy Studies

Titin - Exon 303

Details for Exon 303 of the Titin gene - Sequence Coordinates, Associated Transcripts, Functional Data, Truncating Variants and Sequence.

The exon number is based on the LRG numbering, as recommended for clinical reporting.

Coordinates

The genomic coordinates of HG19 and Locus Reference Genomic (LRG) and the CDS coordinates of the Titin meta-transcript for exon 303 are displayed below.

HG19 Genomic HG38 Genomic Locus Reference Genomic Meta-Transcript
StartEnd StartEnd StartEnd StartEnd
179,457,004 179,456,705 178,592,277 178,591,978 243,526 243,82559,627 59,926

Transcripts

Exon 303 occurs in the following Titin transcripts (the number indicates the exon rank of exon 303 in each transcript).

METAN2BAN2BN2ANOVEX-1NOVEX-2NOVEX-3
302 252 130 251 131 131 -

Functional Data

Region: This exon occurs in the A-band region of the titin protein.

Domains: This exon codes for the following domain(s) - Fibronectin type-III 32.

PSI: The "proportion spliced-in" (an estimate of the percentage of TTN transcripts that incorporate this exon based on RNAseq data) is 100% in DCM (LV tissue of 84 end-stage patients) and 91% in GTEx (LV tissue of 105 samples from Genotype-Tissue Expression project). (See Ref. 1 for details)

Symmetry: This exon is symmetric, i.e. the length of the exon is a multiple of three and therefore removal of it will not alter the reading frame.

References
1. A. M. Roberts, J. S. Ware, D. S. Herman et al. Integrated allelic, transcriptional, and phenomic dissection of the cardiac effects of titin truncations in health and disease. Sci. Transl. Med. 7, 270ra6 (2015).

Truncating Variants

The following TTN truncating variants affecting this exon have been described in major published studies (click on the study name for more details):

StudyCohortPatient IDVariant (CDS)Variant (protein)Variant Type
STM 2015DCM-ES20VW01643c.59627-1G>Aessential splice site
NEJM 2012DCM-AMGR-11c.59926+1G>Aessential splice site
NEJM 2012DCM-B UK-B12c.59627-1G>Aessential splice site

The shaded variants are from a cohort (DCM-B of the 2012 NEJM study) that was also included in the 2015 STM study (DCM-ES cohort) and therefore represent redundant mutations.

Sequence

Size of Exon: 300 bases           Ensembl ID: ENSE00002226829

ATAAACCTGGGCCACCTAGAGATCTGGAAGTCAGTGAAATTAGGAAAGATTCATGTTACCTTACTTGGAAAGAACCACTGGATGATGGTGGTTCTGTTATTACCAATTATGTGGTTGAGA
GGAGAGATGTTGCCAGCGCCCAGTGGTCACCTCTCTCAGCTACATCAAAGAAAAAGAGTCACTTCGCTAAGCATCTGAATGAAGGCAACCAGTACCTCTTCCGAGTAGCTGCGGAGAACC
AGTATGGACGTGGTCCTTTTGTTGAAACACCAAAACCAATCAAGGCTTTGGATCCTCTCC

ATGC = coding sequence, ATGC = non-coding sequence