In the late seventies an unknown cause of incoordination and weakness began being recognized in horses less than three years old. Usually the disease began between four and eight months of age and was slowly progressive, usually stopping short of completely incapacitating the horse. Now labelled equine neuroaxonal dystrophy (END) or degenerative myeloencephalopathy (EDM), has turned out to be one of the common causes of incoordination in young horses, rivaling Wobblers or vertebral malformation. Genetics and vitamin E have a role in this disease.

The exact pathogenesis of this disease in unknown but heredity and vitamin E both play a role in this disease. Though the role of Vitamin E is unclear there is strong evidence to show that low Vitamin E levels play a role in causing this disease. Interestingly some of the horses with this disease have adequate intake, but blood levels remain low. Some research has been done: An oral vitamin E absorption test was performed, and results for eight affected horses and the affected stallion were compared with results of four of the monitored control horses and four additional control horses. Significant differences were not evident in any of the absorption on vitamin E. On the basis of data from this study and supported by reported prophylactic and therapeutic benefits of supplemented vitamin E, low plasma concentration of vitamin E is concluded to be a factor in the development of EDM in the first year of life of hereditarily predisposed foals. It was also concluded that the significantly lower alpha-tocopherol values seen in the foals in this study did not reflect a primary gastrointestinal tract absorption problem (reference below) . This may indicate a genetic disease that impairs vitamin E's efficiency at preventing oxidative injury to the nervous tissue. ...more.