Amyotrophic lateral sclerosis (ALS) which is one of representative neurodegenerative disorders is characterized by selective death of motor neurons. 20% of all familial ALS cases are associated with mutations of Cu-Zn superoxide dismutase(SOD1) and gain-of-function is known as one of pathomechanisms of ALS. But, the mechanism of late-onset disease manifestation despite the innate mutation has no clear explanation.The pathomechanisms of ALS, as reported to date, are glutamate-induced excitotoxicity, autoimmunity, SOD1 mutation induced oxygen radicals, and protein aggregation et al. Recently, the cytotoxicity of homocysteine(HC) is known to contribute to an attack of ALS through production of copper-mediated oxygen radicals, stimulation of excitotoxic amino acid receptor, NO-mediated cytotoxicity and DNA damage. The relationship between homocysteine (HC) and amyotrophic lateral sclerosis (ALS) has not been investigated, in spite of the similarity in their pathogenesis.

Keywords: Amyotrophic lateral sclerosis (ALS), Pathomechanism, Glutamate, Supero-xide dismutase (SOD), Protein aggregation, Autoimmunity, Homocysteine