The term “Apollo Disease” is an informal name used to describe a complex, progressive neurological disorder that severely impacts a person’s movement and balance. It is a rare condition that affects the nervous system, leading to a combination of distinct physical problems. The symptoms typically develop gradually, making it a late-onset disorder that slowly worsens over time.
The Formal Name of the Condition
The medically recognized name for the condition often called Apollo Disease is Cerebellar Ataxia, Neuropathy, and Vestibular Areflexia Syndrome, abbreviated as CANVAS syndrome. The informal name “Apollo Disease” is not an official designation used by healthcare professionals. CANVAS is a neurodegenerative disorder combining three distinct components affecting the nervous system. The condition typically begins affecting people in their fifth or sixth decade of life, with a slow progression of symptoms.
The Genetic Cause
CANVAS syndrome is an inherited disorder, often following an autosomal recessive pattern. The underlying cause is a mutation in the RFC1 gene, which produces the protein Replication Factor C Subunit 1. This protein plays a role in DNA replication and repair. The mutation is a specific biallelic pentanucleotide repeat expansion. In people with CANVAS, the normal gene sequence is replaced by an abnormally long repeat of the nucleotides AAGGG, disrupting the gene’s function and leading to the progressive deterioration of sensory nerves and coordination centers in the brain.
Primary Physical Manifestations
The syndrome is defined by the simultaneous presence of three core physical manifestations reflecting damage to different parts of the nervous system.
Cerebellar Ataxia
Cerebellar Ataxia involves poor muscle control and coordination due to damage in the cerebellum, the brain region responsible for movement. This leads to an unsteady, wide-based gait, difficulties with fine motor tasks, and slurred speech (dysarthria).
Sensory Neuropathy
Sensory Neuropathy is a disorder of the sensory nerves, particularly those that carry information about body position, called proprioception. This loss of sensation and awareness in the limbs makes it challenging for a person to know where their feet are in space, contributing to balance problems.
Vestibular Areflexia
Vestibular Areflexia signifies a severe loss of reflex function in the inner ear’s balance organs. Damage to the vestibular system causes severe unsteadiness, especially when walking in the dark or on uneven surfaces. It also results in oscillopsia, a sensation where the visual world appears to jump or blur when the head moves.
Diagnosis and Supportive Care
Diagnosing CANVAS syndrome involves a detailed neurological examination to identify the classic triad of symptoms. Specialists perform specific balance and vestibular function tests, such as a video head impulse test, to confirm the loss of inner ear reflexes. Electrophysiological testing, like nerve conduction studies, can confirm the presence of sensory neuropathy. The definitive diagnosis relies on genetic testing for the characteristic AAGGG pentanucleotide repeat expansion in the RFC1 gene. Currently, there is no cure or treatment available to stop the progression of CANVAS syndrome. Management is supportive and focused on maximizing function and safety.
Supportive Therapies
- Physical therapy helps maintain mobility and muscle strength.
- Occupational therapy assists with adapting daily activities and recommending assistive devices like canes or walkers.
- Vestibular rehabilitation therapy helps the brain compensate for the loss of inner ear function.