Idiopathic NBIA is of unknown origin, although it is suspected to be genetic.
For many families, the person diagnosed with NBIA is the first and only affected individual, so it is difficult to know whether there is a specific pattern of inheritance. Although, it is thought that most of these cases are probably recessive because some families have more than one affected child and idiopathic NBIA is more common in families in which the parents are related, such as distant cousins. That would make it more likely that they share a recessive gene.
The symptoms are more varied because there are probably several different causes of neurodegeneration for individuals in this group. As with other forms of NBIA, the idiopathic form features early- and late-onset types. About 35 percent of those diagnosed with NBIA are believed to be in this group.
Clinical Diagnosis of Idiopathic NBIA
Suspicion of NBIA usually arises when an MRI of the brain shows excessive iron accumulation, along with a movement disorder. Depending on symptoms, genetic testing is done to rule out other forms of NBIA. If all are negative, but the findings are characteristic of NBIA, then the diagnosis of Idiopathic NBIA is given until further evidence of the genetic origin or another cause is determined.
Evaluations Following Initial Diagnosis
Neurologic examination for movement disorders, including dystonia, rigidity, spasticy and choreoathetosis, which are involuntary movements that include contractions, twisting and writhing. Walking ability and speech also are assessed.
An eye exam to check for such problems as retinopathy (damage to the small blood vessels in the retina) and optic atrophy (the loss of some or most of the fibers of the optic nerve).
Developmental screening, with referral for more formal testing if delay is indicated.
Assessment to see if physical therapy, occupational therapy and/or speech therapy are warranted.
Assessment of behavior and neuropsychiatric changes.
Medical genetics consultation.
Managing Idiopathic NBIA
Doctors treat patients with medication when appropriate. Also, affected individuals may need a feeding tube or other assistance to achieve adequate nutrition. Other therapies might also be warranted.
Please visit the NBIA Disorders Association website, which was used as a primary source for the above information.