SMN1 and hyperinsulinemic hypoglycemia, familial, 4: Specifically, environmental factors may influence SMA through three distinct pathways: (1) as downstream sequelae of SMN deficiency, exemplified by nutritional intake difficulties resulting from motor dysfunction; (2) as disease modifiers that regulate SMN2 gene expression through alterations in epigenetic modifications; and (3) as independent pathological factors that directly accelerate motor neuron degeneration through mechanisms such as oxidative stress.