What is NBIA?

NBIA means Neurodegeneration with Brain Iron Accumulation and is the generic term for a group of progressive and as yet incurable neurological diseases that usually begin in childhood or adolescence and are genetically determined. Neurodegeneration means the loss of nerve cells. All NBIA variants are also characterized by abnormal iron deposition in the brain nuclei, the so-called basal ganglia. These are responsible for regulating movement, among other things. The relationship between iron accumulation and symptoms is not yet fully understood.

Developmental and movement disorders, behavioral abnormalities, cognitive impairment, visual or speech impairment, or epilepsy may be early signs, depending on the NBIA variant. A clinical suspicion of NBIA is confirmed and specified by genetic testing or MRI imaging. If you have just learned of an NBIA diagnosis, please also read this special information: Newly diagnosed

Many patients develop pronounced dystonia. These are involuntary spasms of the musculature that lead to incorrect postures and over-movements. Spasticity, ataxia, chorea, neuropathy and parkinsonism may also occur in varying degrees of severity. The movement disorders usually lead to wheelchair use. The speech and swallowing disorders may involve respiratory and feeding problems. Retinal or optic nerve degeneration, severe epilepsy, and psychiatric difficulties including dementia are possible, depending on the NBIA variant.

NBIA is progressive, sometimes with prolonged disease arrest between short periods of rapid deterioration. As the disease progresses, complications can occur and life expectancy is significantly shortened. There are currently only limited effective therapies, particularly for muscle relaxation, which may provide temporary relief but do not stop the progression. For PKAN, there are initial clinical trials with drugs that address the cause of the disease (see Research).

The graphic shows the 15 currently known NBIA variants, each of which is due to a mutation in a different gene. With an estimated prevalence of less than 10 affected individuals per 1 million, NBIA is very rare. The four most common NBIA variants are BPAN, PKAN, PLAN, and MPAN. Only a small proportion of affected individuals carry mutations in any of the 11 other known genes, or the cause of iron storage in the brain is still completely unknown (idiopathic NBIA). Each NBIA variant has a different characteristic course of disease with differently pronounced but partly similar symptoms, because the fact that different genes are affected means that other metabolic processes are also disturbed in each NBIA variant.

Click on an abbreviation in the graphic for specific information on each NBIA variant. For basic information on NBIA inheritance, see: Genetics