What is NBIA?

NBIA means neurodegeneration with iron accumulation in the brain. 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. In simple terms, NBIA diseases can be thought of as a mixture of Parkinson's and dementia in childhood. In those affected, this manifests itself in progressive movement and developmental disorders. Very rarely, the first symptoms do not appear until adulthood.

Neurodegeneration means the loss of nerve cells. All NBIA diseases are also characterized by an abnormal deposition of iron in the brain nuclei, the so-called basal ganglia. These are responsible for regulating movement, among other things. The connection between iron accumulation and symptoms is not yet fully understood. Other metabolic processes specific to each NBIA disease are probably of greater importance.

Developmental and movement disorders, behavioral abnormalities, cognitive impairments, visual or speech disorders or epilepsy can be the first signs, depending on the NBIA disease. A clinical suspicion of NBIA is confirmed and specified by genetic testing or MRI imaging. If you have just been diagnosed with NBIA, please also read this special information: Newly diagnosed

Many patients develop pronounced dystonia. These are involuntary spasms of the muscles that lead to incorrect posture and excessive movements. Spasticity, ataxia, chorea, neuropathy and parkinsonism can also occur in varying degrees. The movement disorders usually lead to wheelchair dependency. Speech and swallowing disorders can lead to breathing and feeding problems. Retinal or optic nerve degeneration, severe epilepsy and psychiatric difficulties up to and including dementia are possible, depending on the NBIA disease.

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

The diagram shows the currently known NBIA diseases, each of which is caused by a mutation in a different gene. With an estimated prevalence of less than 10 affected people per 1 million, NBIA is very rare. The four most common NBIA diseases are BPAN, PKAN, PLAN and MPAN. Only a small proportion of those affected carry mutations in one of the other known genes or the cause of iron storage in the brain is still completely unknown (idiopathic NBIA).

Each NBIA disease has a different characteristic course with different but sometimes similar symptoms, because different genes are affected and different metabolic processes are disrupted in each NBIA disease.

Click on an abbreviation in the chart for specific information on each NBIA disorder. Basic information on the inheritance of NBIA can be found at: Genetics