Entrez ID	Official symbol	Synonyms	Description	Location	Type of protein	External annotation
7273	TTN	CMD1G, CMH9, CMPD4, EOMFC, HMERF, LGMD2J, LGMDR10, MYLK5, SALMY, TMD	titin	2q31.2	protein-coding	Genecard

uniprot_summary

refseq_summary

Key component in the assembly and functioning of vertebrate striated muscles. By providing connections at the level of individual microfilaments, it contributes to the fine balance of forces between the two halves of the sarcomere. The size and extensibility of the cross-links are the main determinants of sarcomere extensibility properties of muscle. In non-muscle cells, seems to play a role in chromosome condensation and chromosome segregation during mitosis. Might link the lamina network to chromatin or nuclear actin, or both during interphase.

This gene encodes a large abundant protein of striated muscle. The product of this gene is divided into two regions, a N-terminal I-band and a C-terminal A-band. The I-band, which is the elastic part of the molecule, contains two regions of tandem immunoglobulin domains on either side of a PEVK region that is rich in proline, glutamate, valine and lysine. The A-band, which is thought to act as a protein-ruler, contains a mixture of immunoglobulin and fibronectin repeats, and possesses kinase activity. An N-terminal Z-disc region and a C-terminal M-line region bind to the Z-line and M-line of the sarcomere, respectively, so that a single titin molecule spans half the length of a sarcomere. Titin also contains binding sites for muscle associated proteins so it serves as an adhesion template for the assembly of contractile machinery in muscle cells. It has also been identified as a structural protein for chromosomes. Alternative splicing of this gene results in multiple transcript variants. Considerable variability exists in the I-band, the M-line and the Z-disc regions of titin. Variability in the I-band region contributes to the differences in elasticity of different titin isoforms and, therefore, to the differences in elasticity of different muscle types. Mutations in this gene are associated with familial hypertrophic cardiomyopathy 9, and autoantibodies to titin are produced in patients with the autoimmune disease scleroderma.

Caregory	Description	Value	Value range ( Low - High )	Comment
PLI	The probability of being loss-of-function (LoF) intolerant	-	[0, ..., 1]	Genes with high pLI scores (pLI ≥ 0.9) are extremely LoF intolerant, whereby genes with low pLI scores (pLI ≤ 0.1) are LoF tolerant. The score is calculated based on high-quality exome sequence data (ExAC) for 60,706 individuals of diverse ethnicities.
Haploinsufficiency (HI) score rank	Predicted probability of exhibiting haploinsufficiency		[100, ..., 1]	High ranks (e.g. 0-10%) indicate a gene is more likely to exhibit haploinsufficiency, low ranks (e.g. 90-100%) indicate a gene is more likely to NOT exhibit haploinsufficiency (DECIPHER, PMID: 20976243). haploinsufficiency means a single functional copy of a gene is insufficient to maintain its normal function and is extremely intolerant of LoF variation.
Gene brain expressed	Queried gene is expressed in brain tissues	Flase	[False, True]	The gene expression data are extracted from GTEx v7 and BrainSpan. A gene with the expression value of (log 2 based (TPM+1)) at least 1 TPM/RPKM/FPKM in one or more tissues related to the brain is considered brain-expressed.
Protein brain expressed	Queried protein is expressed in brain tissues	True	[False, True]	The protein expression data are extracted from ProteomicsDB (v2018.09). A protein with the expression value of (log based 10 (iBAQ intensity)) at least 0.5 in one or more tissues related to the brain is considered brain-expressed protein.
Carrying LoF DNMs	Number of loss-of-function DNMs hit the queried gene	8 (Case)	[0, ..., 67] with average of 0.160	Loss of function (LoF) mutations include frameshift indels, nonsense (stop-gained) and splice-site mutations, which can result in the gene product having less or no function and can have deleterious consequences.
		1 (Control)	[0, ..., 6] with average of 0.044
Carrying missense DNMs	Number of missense DNMs hit the queried gene	55 (Case)	[0, ..., 55] with average of 0.846	Missense mutations can result in changes in protein sequences, but are commonly considered to have less deleterious impacts than LoF mutations.
		21 (Control)	[0, ..., 21] with average of 0.300
FMRP binding targets	FMRP inteacting parters	False	[False, True]	FMRP loss of function causes Fragile X syndrome (FXS). The binding targets identified crosslinking immunoprecipitation (HITS-CLIP) in mouse brains (PMID:21784246). Many FMRP targets are among genes implicated in different neuropsychiatric diseases, such as autism, schizophrenia.
Postsynaptic density (PSD)	Protein associates with postsynaptic membranes of excitatory synapses	False	[False, True]	Abnormalities with PSD proteins are linked to various neuropsychiatric diseases including neurodevelopmental disorders.
Human essential genes	-	True	[False, True]	Genes are thought to be critical for human survival.