Features include always present findings: Global developmental delay; and very common findings: Ptosis. 33 total HPO annotations.

CSPP1 encodes centrosome and spindle pole associated protein 1 (1,256 aa). May play a role in cell-cycle-dependent microtubule organization Highest expression in Testis (24.0 TPM) and Brain Cerebellar Hemisphere (10.9 TPM).

Joubert syndrome 21 is caused by mutations in the CSPP1 gene on chromosome 8.

CSPP1 is classified as a druggable target with score 0.0.

Genetic testing for CSPP1 is available. Testing is considered confirmatory for diagnosis.

Phenotype severity distribution: 1 always present feature, 1 very common feature, 1 common feature.

No clinical trials have been registered for Joubert syndrome 21.

5 publications have been identified in PubMed for Joubert syndrome 21. Research spans Case Report / Case Series (40%), Basic Science / Preclinical (40%), and Review / Meta-Analysis (20%).

Recent Publications

• Hakeem A (2025). [PMID: 39781470](https://pubmed.ncbi.nlm.nih.gov/39781470/). *International journal of biological sciences*. [Basic Science / Preclinical]

• Saunders HAJ (2025). [PMID: 39856351](https://pubmed.ncbi.nlm.nih.gov/39856351/). *Nature structural & molecular biology*. [Basic Science / Preclinical]

• Acosta-Paguada LF (2025). [PMID: 40898267](https://pubmed.ncbi.nlm.nih.gov/40898267/). *Journal of medical case reports*. [Case Report / Case Series]

• Wei C (2024). [PMID: 38586154](https://pubmed.ncbi.nlm.nih.gov/38586154/). *Frontiers in pediatrics*. [Case Report / Case Series]

• Grlić S (2024). [PMID: 38671609](https://pubmed.ncbi.nlm.nih.gov/38671609/). *Children (Basel, Switzerland)*. [Review / Meta-Analysis]