This disease is a familial hereditary disorder characterized by degeneration of the posterior spinal cord and cerebellum.

bubble_chart Pathological Changes

The spinal cord is visibly thinner than normal, with grade I cerebellar atrophy. The histological changes in the spinal cord are characterized by degeneration of the posterior columns, lateral corticospinal tracts, and spinocerebellar tracts. The lesions in the posterior columns are particularly prominent, accompanied by widespread gliosis. The cerebellum and brainstem are mostly normal, though the pons and medulla may show shrinkage, with no significant changes in the cerebral cortex. The spinal cord lesions are more severe in the lower regions and gradually lessen as they approach the medulla oblongata.

bubble_chart Clinical Manifestations

The typical age of onset is adolescence, with some cases occurring in adulthood. Family members tend to develop the disease at similar ages, though severity varies. Symptoms develop gradually, with the most common being ataxia in the lower limbs, resulting in an unsteady gait, often compensated by swinging the arms to maintain balance. Standing also becomes unstable, though not necessarily worsened by closing the eyes. Later, ataxia affects the trunk and upper limbs, leading to illegible handwriting or even an inability to write. Limb and head tremors may occur, along with chorea-like or myoclonic involuntary movements. Approximately 70% of patients exhibit nystagmus, which can be horizontal, vertical, or rotatory. Speech impairment is another hallmark of the disease, characterized by slow, monotonous, slurred, or fragmented speech, sometimes explosive or excessively prolonged, with occasional abrupt acceleration. Deep tendon reflexes are absent. Upper limb reflexes may persist initially but disappear in later stages. The Babinski reflex is often extensor, and pyramidal tract damage can increase muscle tone, transforming the ataxic gait into a spastic one. Patients may experience lightning-like limb pain, though superficial sensory deficits are rare. Position and vibration sense are diminished or lost, particularly in the lower limbs. Other manifestations include optic atrophy, retinal pigmentation, ptosis, abnormal pupillary reflexes, and ophthalmoplegia. Occasionally, hearing loss, vestibular dysfunction, and dysphagia occur. Autonomic dysfunction may lead to tachycardia, nausea, vomiting, hypothermia, diabetes, sexual dysfunction, and sphincter disturbances. Skeletal deformities such as kyphoscoliosis, pes cavus, and talipes equinovarus may develop. Cardiac involvement includes cardiomegaly, murmurs, ECG abnormalities, valvular disease, myocardial dystrophy, conduction block, and heart failure, which can cause sudden death.

There is no specific treatment method. To correct foot deformities, tendon transfer, lengthening, or joint fusion may be performed.

bubble_chart Differentiation

The gait in this disease is unsteady and staggering, with impaired fine motor skills in both hands. When the pyramidal tract is not involved, there may be increased muscle tone, and pathological reflexes resemble those of cervical myelopathy. However, the latter lacks ataxia, cranial nerve involvement, and speech disorders. MRI often reveals degenerative cervical stenosis.