A 3-year, 9-month-old boy had signs of mild gait impairment that started at age 2. He had strikingly curly, pale hair, unlike that of his parents. On chemical analysis his hair showed a decrease in disulfide bonds and an increase in thiol groups. Greatly enlarged axons packed with neurofilaments were found on biopsy in motor and sensory nerves. The diagnosis of giant axonal neuropathy may be suspected from the presence of signs of peripheral neuropathy in a patient with tightly curly, pale scalp hair, unlike that of his parents. The diagnosis can be proved by sural nerve biopsy.