This report describes Charcot-Marie-Tooth disease, type 4J (CMT4J), which is a subtype of Charcot-Marie-Tooth disease. It is one of several diseases associated with the human gene FIG4. See the human disease model report for neurodegenerative disease, FIG4-related (FBhh0000336).
Variant(s) implicated in human disease tested (as analogous mutation in fly gene): I46T in the fly FIG4 gene (corresponds to I41T in the human FIG4 gene), implicated in ALS11 and CMT4J; L22P in the fly FIG4 gene (corresponds to L17P in the human FIG4 gene), implicated in CMT4J.
[updated Jul. 2017 by FlyBase; FBrf0222196]
Charcot-Marie-Tooth disease (CMT) constitutes a clinically and genetically heterogeneous group of hereditary motor and sensory peripheral neuropathies. CMT is divided into several major types: Type 1 is characterized by demyelination and by a significantly slowed motor median nerve conduction velocity (NCV). Type 2 is characterized by axonal abnormalities and a normal or slightly reduced NCV. "Intermediate" types describe CMT families with nerve conduction velocities, in different affected individuals, that overlap the division between Type 1 and Type 2. Additional types are defined on the basis inheritance patterns. [from MIM:609260 and MIM:606482; 2015.12.15]
Symptoms typically include progressive distal muscle weakness and atrophy, often associated with mild to moderate sensory loss, depressed tendon reflexes, and high-arched feet. [from Gene Reviews, http://www.ncbi.nlm.nih.gov/books/NBK1358 2015.12.15]
[CHARCOT-MARIE-TOOTH DISEASE, TYPE 4J; CMT4J](https://omim.org/entry/611228)
[FIG4 PHOSPHOINOSITIDE 5-PHOSPHATASE; FIG4](https://omim.org/entry/609390)
See description of different CMT classification types, above.
CMT4JJ is caused by compound heterozygous mutations in the FIG4 gene. [from MIM:611228; 2016.06.16]
FIG4 Phosphoinositide 5-Phosphatase (FIG4) encodes a protein in the SAC domain-containing protein family; the SAC domain incorporates the phosphoinositide phosphatase activity. Membrane-bound phosphoinositides function as signaling molecules and play a key role in vesicle trafficking in eukaryotic cells. [from Gene Cards, FIG4; 2016.06.22]
One to one: 1 human to 1 Drosophila.
Ortholog of human FIG4 (1 Drosophila to 1 human). Dmel\FIG4 shares 41% identity and 58% similarity with the human gene.
