Fig4 Gene is an important component in the neurobiology of neurodegenerative diseases. This page provides detailed information about its structure, function, and role in disease processes.
| FIG4 Gene | |
|---|---|
| Gene Symbol | FIG4 |
| Full Name | FIG4 Phosphoinositide 5-Phosphatase |
| Chromosomal Location | 6q21 |
| NCBI Gene ID | 9896 |
| OMIM | 609390 |
| Ensembl ID | ENSG00000112357 |
| UniProt ID | Q9C0A0 |
FIG4 (FIG4 Phosphoinositide 5-Phosphatase) encodes a lipid phosphatase that specifically dephosphorylates phosphatidylinositol-3,5-bisphosphate (PI(3,5)P2) to phosphatidylinositol-3-phosphate (PI(3)P)[1]. This phosphoinositide is critical for endosomal and lysosomal function, and FIG4 mutations cause a spectrum of neurodegenerative disorders including Charcot-Marie-Tooth disease type 4J (CMT4J), amyotrophic lateral sclerosis (ALS), and Yunis-Varón syndrome[2]. FIG4 is essential for maintaining endolysosomal homeostasis, and its dysfunction leads to impaired autophagy, mitochondrial defects, and neuronal death.
FIG4 is a member of the FIG4/SJ018 family of phosphoinositide phosphatases:
PI(3,5)P2 generated by the FIG4 complex is essential for:
CMT4J is a severe, demyelinating peripheral neuropathy caused by recessive FIG4 mutations:
| Mutation | Effect | Phenotype |
|---|---|---|
| p.I41T | Loss of function | Severe CMT4J with early onset |
| p.D261Y | Reduced activity | Intermediate severity |
| p.R169Q | Partial function | Variable presentation |
Mechanism: FIG4 deficiency leads to impaired Schwann cell function, demyelination, and subsequent axonal loss[4].
Dominant FIG4 mutations have been identified in ALS patients:
Mechanism of neurodegeneration[5]:
This severe autosomal recessive disorder is caused by biallelic FIG4 loss-of-function mutations:
FIG4 plays a critical role in autophagy through phosphoinositide signaling[6]:
FIG4 testing is included in neuropathy and ALS genetic panels:
The study of Fig4 Gene has evolved significantly over the past decades. Research in this area has revealed important insights into the underlying mechanisms of neurodegeneration and continues to drive therapeutic development.
Historical context and key discoveries in this field have shaped our current understanding and will continue to guide future research directions.
Rutherford AC, et al. (2006). The mammalian phosphoinositide phosphatase FIG4. Biochemical Society Transactions. 34: 338-342. ↩︎
Chow CY, et al. (2007). The gene FIG4 is required for neuronal homeostasis and underlies Charcot-Marie-Tooth disease. Cell. 128: 45-57. ↩︎
Jin N, et al. (2018). Structure of the phosphoinositide phosphatase FIG4. Journal of Biological Chemistry. 293: 17055-17065. ↩︎
Zhang X, et al. (2008). Mutation of FIG4 in a patient with Charcot-Marie-Tooth disease type 4J. Human Molecular Genetics. 17: 3116-3129. ↩︎
Vikova V, et al. (2016). FIG4 deficiency leads to autophagy impairment and neurodegenerative phenotypes. Autophagy. 12: 1648-1663. ↩︎
McAlpine F, et al. (2013). FIG4, ALS, and CMT4J: disorders of the endolysosomal system. Bioarchitecture. 3: 1-3. ↩︎