The genetic mutations associated with most cases of familial MND remain unknown.
Researchers from Japan have shown that there are mutations in the gene encoding optineurin (OPTN) in some patients with MND. The optineurin protein has been suggested to have many functions ranging from inflammation induction to shuttling large molecules around the cell. Laboratory experiments showed that the toxicity of OPTN mutations may result from deregulation of a switch that can activate specific genes or as a consequence of accumulation of the optineurin protein into protein ‘junkpiles' known as deposits. Interestingly, the researchers discovered that optineurin could be found in protein deposits along with TDP-43 and SOD1 in sporadic and SOD1 associated MND respectively.
Source: International MND research update - June 2010, Dr Justin Yerbury for MNDRIA