Neuroaxonal dystrophy associated with vitamin E deficiency in two Haflinger horses.

The study reveals neuroaxonal dystrophy, a kind of neurological disorder, and minimal diffuse degenerative myelopathy in two young Haflinger horses likely associated with vitamin E deficiency. The horses exhibited specific symptoms, and researchers concluded that the condition might be inherited but more investigation is needed to confirm if the disorder is directly linked to the vitamin deficiency.

Study Subject and Diagnosis

• The study was conducted on two female Haflinger horses, aged 1 and 2 years, who were full siblings.
• Both the horses had been developing slow progressive ataxia or loss of control of bodily movements since they were 4 months old.
• More prominent symptoms were observed in the hind legs including hypermetria and dysmetria which relate to miscalculations in distance and speed of movements.
• Through a histological examination, the horses were diagnosed with neuroaxonal dystrophy, characterized by certain abnormalities in nervous tissue structures.

Disease Manifestation and Symptoms

• Abnormalities caused by neuroaxonal dystrophy included spheroid formation, vacuolation (formation of vacuoles or cavity), astrogliosis (increased activity of astrocytes in the central nervous system), and deposition of lipofuscin pigment (a sign of aging or damage) in macrophages (a type of white blood cell) and neuronal cell bodies.
• These changes were confined to specific areas of the nervous system, including the gracilis and cuneate nuclei, nucleus of the solitary tract, nucleus intermediomedialis in the sacral and the seventh segment of the cervical spinal cord and, additionally, in the medial vestibular nucleus in the older horse.

Biochemical Observations

• It was found that both the horses had significantly less serum alpha- and gamma-tocopherol, forms of vitamin E.
• The total lipid concentrations and serum selenium values in their blood were found to be normal.

Possible Causes of the Disorder

• A potential hereditary basis for the condition in these horses was proposed by the researchers due to the familial relationship of the subjects.
• A link between neuroaxonal dystrophy and vitamin E deficiency was suggested but not confirmed. The researchers indicated a need for further studies to establish the correlation definitively.