Infantile neuroaxonal dystrophy (INAD) is a very rare, hereditary chronic disorder of the nervous system. It is characterized by irregularities of nerve endings (axon terminals) within the brain and spinal cord (central nervous system) and outside the central nervous system (peripheral nerves and terminals). In most cases, infants and children with INAD appear to grow normally until approximately 14 to 18 months of age. After that, they may begin to experience an increased difficulty in walking.
Some infants may experience symptoms at approximately six to eight months of age. They may suffer delays or an arrest in the acquisition of skills requiring the coordination of mental and physical activities (delayed psychomotor development).
The signs and symptoms associated with infantile neuroaxonal dystrophy result from swelling and degeneration of individual nerve endings (dystrophic axonal swellings or "spheroids") within and outside the brain and spinal cord (central nervous system). In most cases, INAD is inherited as an autosomal recessive genetic trait.
Until lately, INAD could be diagnosed by examining a piece of skin or conjunctiva under a microscope. The examiners would then confirm the presence of the ‘spheroid bodies’ in the nerve axons contained within it. Spheroid bodies are found in other related, but different, disorders, but the symptoms the children have, and the age at which they appear, along with laboratory results, confirm the diagnosis.
Now, testing of the PLA2G6 gene on a blood sample will be done first to detect INAD which may confirm the diagnosis without the need for the biopsies.
Read more articles on Infantile Neuroaxonal Dystrophy.