TTC21A
Tetratricopeptide Repeat Domain 21A
Gene Information Card
| Symbol | TTC21A |
|---|---|
| Full Name | Tetratricopeptide Repeat Domain 21A |
| Gene Type | Protein coding |
| Chromosomal Location | 3q22.3 |
| NCBI Gene ID | 199223 ncbi.nlm.nih.gov/gene/199223 |
| Ensembl ID | ENSG00000168026 |
| UniProt ID | Q8N9N8 |
| OMIM ID | 611430 |
| HGNC ID | 25687 |
| Aliases | IFT139, TTC21A, NPH12, JBTS19 |
Description
TTC21A encodes a tetratricopeptide repeat (TPR)-containing protein that is a component of the intraflagellar transport (IFT) complex A. This protein is essential for retrograde ciliary transport and ciliary assembly. Mutations in TTC21A cause ciliopathies, including nephronophthisis (NPH12) and Joubert syndrome (JBTS19), due to impaired ciliary function.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Nephronophthisis 12 (NPH12) | Loss-of-function mutations disrupt retrograde IFT, leading to defective ciliary signaling and renal tubular degeneration. | ClinVar, OMIM |
| Joubert syndrome 19 (JBTS19) | Biallelic mutations impair ciliary transport, causing cerebellar and retinal abnormalities. | OMIM, PubMed |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Kidney | 12.5 | Medium |
| Testis | 8.3 | Medium |
| Lung | 6.1 | Low |
| Brain | 5.4 | Low |
| Liver | 4.2 | Low |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| HEK 293 | 15.2 | Embryonic kidney cells |
| HepG2 | 8.7 | Liver cancer cells |
| A549 | 6.3 | Lung cancer cells |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.626G>A (p.Arg209His) | Missense | Rare | Likely pathogenic; disrupts TPR domain |
| c.1240C>T (p.Arg414*) | Nonsense | Rare | Loss of function; truncation |
| c.1873_1874del (p.Leu625fs) | Frameshift | Rare | Loss of function; premature stop |
Mutation functional classification
Loss of Function (LOF)
Most TTC21A mutations are loss-of-function, leading to reduced or absent protein function and ciliary defects.
Gain of Function (GOF)
No evidence of gain-of-function mutations.
Dominant Negative (DN)
Not reported; disease is autosomal recessive.
View complete mutation data：
Gene Ontology (GO)
| • cytoplasm (GO:0005737) | • intraflagellar transport complex A (GO:0030992) |
| • intraciliary retrograde transport (GO:0035721) | • cilium assembly (GO:0060271) |
| • protein binding (GO:0005515) |
Pathways
• Intraflagellar transport (IFT)
• Ciliopathy pathway
Protein Summary
TTC21A (IFT139) is a 1315-amino acid protein containing multiple tetratricopeptide repeats that mediate protein-protein interactions within the IFT-A complex. It localizes to the ciliary base and axoneme, facilitating retrograde transport of cargo from the ciliary tip to the cell body. Defects in this protein disrupt ciliary signaling and are linked to renal and neurological ciliopathies.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| TTC21A Knockout HEK293 Cell Line | EDJ-KQ10946 | Human | 199223 | Details Get a Quote |
| TTC21A Knockout A-549 Cell Line | EDJ-KQ40021 | Human | 199223 | Details Get a Quote |
| TTC21A Knockout HCT 116 Cell Line | EDJ-KQ40022 | Human | 199223 | Details Get a Quote |
| TTC21A Knockout HeLa Cell Line | EDJ-KQ40023 | Human | 199223 | Details Get a Quote |
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