Background of the antigen
FIG4 is a 907 amino acid protein that contains one SAC domain through which it is thought to function as a phosphoinositide phosphatase that may play an important role in signal transduction and vesicle trafficking. Defects in the gene encoding FIG4 are the cause of Charcot-Marie-Tooth disease type 4J (CMT4J) and amyotrophic lateral sclerosis type 11 (ALS11), both of which negatively affect the nervous system. CMT4J is a recessive demyelinating disorder of the peripheral nervous system and is characterized by reduced motor nerve conduction velocities and axonal degeneration. Unlike CMT4J, ALS11 is characterized by the degeneration of upper motor neurons in the brain and lower neurons in the spinal cord, causing paralysis and, ultimately, death.
