Giant axonal neuropathy (GAN) is an inherited condition involving dysfunction of a specific type of protein in nerve cells (neurons). The protein is essential for normal nerve function because it forms neurofilaments. Neurofilaments make up a structural framework that helps to define the shape and size of the neurons. This condition is characterized by abnormally large and dysfunctional axons, which are the specialized extensions of nerve cells that are required for the transmission of nerve impulses.
Giant axonal neuropathy generally appears in early childhood, (onset is typically 2 1/2 years of age). It progresses slowly as neuronal injury becomes more severe. Signs of GAN usually begin in the peripheral nervous system, which controls movement and sensation in the arms, legs, and other parts of the body. Most individuals with this disorder first have problems with walking. Later they may lose sensation, coordination, strength, and reflexes in their limbs. Hearing and visual problems may also occur. Extremely kinky hair (as compared to others in the family) is characteristic of giant axonal neuropathy.
How do people get giant axonal neuropathy?
This condition is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically don’t show signs and symptoms of the condition.
Currently, there is no cure or treatment for GAN. As the disorder progresses, patients become quadriplegics, dependent on a feeding tube and ventilator. Children who are diagnosed with the disease have a life expectancy no longer than their early twenties while some die much younger.