Features include always present findings: Talipes equinovarus, Distal arthrogryposis, Camptodactyly, and Knee flexion contracture. 18 total HPO annotations.

MYO9A encodes myosin IXA (2,548 aa). Myosins are actin-based motor molecules with ATPase activity. Unconventional myosins serve in intracellular movements. Regulates Rho by stimulating its GTPase activity in neurons. Highest expression in Testis (19.2 TPM) and Nerve Tibial (12.7 TPM).

Myasthenic syndrome, congenital, 24, presynaptic is associated with mutations in the MYO9A gene on chromosome 15.

The MYO9A protein participates in RHOF GAPs stimulate RHOF GTPase activity, RHOD GAPs stimulate RHOD GTPase activity, and RHOQ GAPs stimulate RHOQ GTPase activity pathways.

MYO9A is classified as a druggable target with score 0.0.

Genetic testing for MYO9A is available. Testing is considered confirmatory for diagnosis.

Phenotype severity distribution: 4 always present features.

No clinical trials have been registered for myasthenic syndrome, congenital, 24, presynaptic.

2 publications have been identified in PubMed for myasthenic syndrome, congenital, 24, presynaptic. Research spans Case Report / Case Series (50%) and Epidemiology / Natural History (50%).

Recent Publications

• Zhang J (2025). [PMID: 40442802](https://pubmed.ncbi.nlm.nih.gov/40442802/). *Orphanet journal of rare diseases*. [Epidemiology / Natural History]

• Cotrina-Vinagre FJ (2024). [PMID: 38355957](https://pubmed.ncbi.nlm.nih.gov/38355957/). *Journal of human genetics*. [Case Report / Case Series]