FGD4 encodes FYVE, RhoGEF and PH domain containing 4 (766 aa). Activates CDC42, a member of the Ras-like family of Rho- and Rac proteins, by exchanging bound GDP for free GTP. Plays a role in regulating the actin cytoskeleton and cell shape. Activates MAPK8 Highest expression in Testis (21.7 TPM) and Ovary (21.7 TPM).

Charcot-Marie-Tooth disease type 4H is associated with mutations in the FGD4 gene on chromosome 12.

The FGD4 protein participates in RHOA GEFs activate RHOA, CDC42 GEFs activate CDC42, and RAC1 GEFs activate RAC1 pathways.

FGD4 is classified as a druggable target with score 0.9.

Genetic testing for FGD4 is available. Testing is considered confirmatory for diagnosis.

Phenotype severity distribution: 7 always present features, 4 common features.

Estimated prevalence: <1 in 1,000,000 (VERY_RARE).

1 clinical trial registered, 1 recruiting. Interventions under study include other interventions. Research is primarily sponsored by academic and government institutions.

2 publications have been identified in PubMed for Charcot-Marie-Tooth disease type 4H. Research spans Basic Science / Preclinical (50%) and Epidemiology / Natural History (50%).

Recent Publications

• Cakar A (2025). [PMID: 39776111](https://pubmed.ncbi.nlm.nih.gov/39776111/). *European journal of neurology*. [Epidemiology / Natural History]

• Du N (2024). [PMID: 38835974](https://pubmed.ncbi.nlm.nih.gov/38835974/). *The application of clinical genetics*. [Basic Science / Preclinical]