Beta-propeller protein-associated neurodegeneration

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Beta-propeller protein-associated neurodegeneration (BPAN) is a rare subtype of neurodegeneration with brain iron accumulation disease (NBIA).

It was previously known as static encephalopathy with neurodegeneration in childhood (SENDA), but it was renamed after the underlying genetic abnormality was identified, and named in accordance with the other NBIA.

Clinical presentation

Characteristic clinical features include :

  • global developmental delay during childhood
  • sudden onset of neurocognitive changes during adolescence or young adulthood associated with levodopa resistant parkinsonism, dystonia, and dementia

It was previously known as SENDA because of these clinical features.

Other clinical features include:

  • spastic cerebral palsy
  • spastic quadriplegia

Pathology

Iron accumulation in the brain specifically in globus pallidus and substantia nigra. This disorder is thought to be genetically determined with defective iron metabolism.

It is the only X-linked subtype of NBIA.

Radiographic features 

MRI 

MRI findings are characterized by iron accumulation in the globus pallidus and substantia nigra.

  • T1:
    • hyperintense signal in the globus pallidus (called the "halo sign") and substantia nigra
    • bilateral hypointense central band within paired linear hyperintense signal substantia nigra is virtually pathognomonic
  • T2: markedly hypointense signal in the globus pallidus and substantia nigra

Differential diagnosis