Infantile Neuroaxonal Dystrophy

What is infantile neuroaxonal dystrophy (INAD)?

Infantile neuroaxonal dystrophy (INAD) is a brain condition that affects the nervous system in young children. INAD symptoms start early in a child’s life and get worse over time. The condition is very rare— it affects one in a million children.

INAD is part of a group of disorders called PLA2G6-associated neurodegeneration (PLAN disorders). PLAN disorders are part of a larger group called neurodegeneration with brain iron accumulation (NBIA) disorders.

Children with INAD have too much iron in their brain. They slowly lose their eyesight, muscle control, and everyday skills. Changes in how their eyes move may be an early sign of INAD.

INAD damages axons—the long parts of nerve cells that carry messages from the brain to other parts of the body. When nerve cells get damaged, tiny round clumps form inside or along axons in the brains of children with INAD.

Most children with INAD have a changed version of the PLA2G6 gene. This gene normally helps control the protective outer layer of cells. Finding this changed gene can help doctors diagnose INAD.

Symptoms of INAD

Most children with INAD develop normally for the first months to years of life. Then they begin to lose skills they had learned. Many children start to have symptoms at 6 months old. Almost all children with INAD have symptoms before age 3.

Symptoms of INAD include:

• Muscle weakness or floppiness that later becomes stiffness
• Loss of the ability to sit, crawl, or walk
• Loss of thinking skills (like remembering or paying attention)
• Fast or shaky eye movements and squinting
• Trouble speaking
• Difficulty keeping body temperature normal
• Constipation
• Seizures

Children with INAD may also have different facial features at birth, including:

• A large forehead
• Crossed eyes
• A small nose or jaw
• Ears that sit lower than usual

Who is more likely to get infantile neuroaxonal dystrophy?

INAD is inherited in an autosomal recessive pattern. This means INAD passes from parents to children through genes. A child gets INAD when they inherit a changed gene from both parents. Parents who carry only one changed gene usually don't have symptoms.

People with family members with INAD are more likely to have a child with INAD. If one child has INAD, their siblings have a 25% chance of also having INAD. Genetic counseling can help families understand their chances of having a child with INAD.

How is infantile neuroaxonal dystrophy diagnosed and treated?

Diagnosing INAD

Most children with INAD have changed versions of the PLA2G6 gene. Genetic tests can find these DNA changes and help doctors diagnose INAD. This genetic testing is now the best method for diagnosis.

Doctors once required tissue biopsies to diagnose infantile neuroaxonal dystrophy (INAD) for certain. A doctor may still order a tissue biopsy if genetic testing doesn't give clear results or to support the diagnosis. Doctors use a special microscope to look for signs of nerve damage in cells taken from skin or blood. These changes mirror damage to nerve cells in the brain.

MRI (magnetic resonance imaging) scans may also help diagnose INAD.

Learn more about neurological diagnostic tests and procedures.

Treating INAD

There’s no cure for INAD. Current treatments can’t stop INAD symptoms from getting worse over time. Care for children with INAD focuses on making symptoms as comfortable as possible.

Treatment plans may include medicines to reduce pain or control seizures. Physical therapists can help teach parents and caregivers how to best care for children with INAD. Physical therapy exercises for the arms and legs can help children with INAD stay comfortable.

Prognosis varies based on factors such as the stage of progression, response to treatment, and individual patient characteristics. A healthcare team can discuss your particular situation and provide personalized guidance on your outlook and treatment options.

What are the latest updates on infantile neuroaxonal dystrophy?

The National Institutes of Health (NIH), which includes NINDS, is the leading federal funder of research on the brain and nervous system, including disorders such as INAD. NIH supports new and innovative research to better understand, diagnose, and treat INAD.

NIH-funded research is trying to understand how the PLA2G6 gene works inside cells to identify potential molecular targets for INAD treatments. Also, NIH-funded research on related iron loss-related brain disorders may give clues to better understand INAD and develop future treatments.

For more information on research about INAD, check NIH RePORTER, a searchable database of current and past research projects funded by NIH and other federal agencies. RePORTER also has links to publications and resources from these projects.

For research articles and summaries on INAD, search PubMed, which contains citations from medical journals and other sites.

How can I or my loved one help improve care for people with infantile neuroaxonal dystrophy?

Consider participating in a clinical trial so clinicians and scientists can learn more about INAD and related disorders. Clinical research with human study participants helps researchers learn more about a disorder and perhaps find better ways to safely detect, treat, or prevent disease.

All types of participants are needed—those who are healthy or may have an illness or disease—of all different ages, sexes, races, and ethnicities. This helps make sure that study results apply to as many people as possible, and that treatments will be safe and effective for everyone who will use them.

For information about participating in clinical research, visit the NINDS Clinical Trials site and NIH Clinical Research Trials and You. Learn about clinical trials currently looking for people with INAD at ClinicalTrials.gov, a searchable database of current and past clinical studies and research results.

Learn about related topics

• Neurodegeneration with Brain Iron Accumulation