Pantothenate kinase-associated neurodegeneration

Hallervorden-Spatz syndrome, now known as pantothenate kinase-associated neurodegeneration (PKAN), is an autosomal recessive disorder causing involuntary spasticity and progressive dementia. It is a subset of neurodegeneration with brain iron accumulation (NBIA).

Clinical presentation

Described features include ⁹:

• rigidity
• dysarthria
• dystonia
• retinitis pigmentosa
• progressive mental retardation
• cognitive impairment 
• spasticity
• tremors

Radiographic features

Reflects areas of iron deposition, mainly globi pallidi, substantia nigra, and red nuclei.

MRI

• T2: T2-weighted MRI images often demonstrate hypointense changes in globi pallidi and pars reticulata of substantia nigra
• SWI/T2*: shows susceptibility artefact (low signal) in corresponding areas from iron deposition ⁷

Cortex is usually spared but caudate atrophy may be seen in more advanced cases. The "eye of the tiger" sign refers to a central T2 relatively hyperintense spot (line) within the hypointense globi pallidi due to gliosis and vacualization ³.

MR spectroscopy

• shows decreased NAA peak due to neuronal loss and may show increased myoinositol ⁸ 

History and etymology

It is named after ⁴:

• Hugo Spatz (1888-1969): Anatomist, Munich, Germany
• Julius Hallervorden (1882-1965): Neuropathologist, Germany

Both Hugo Spatz and Julius Hallervorden were involved in the Nazi euthanasia program and, as such, the alternative name is preferred by some authors. Brief biographical entries on Spatz and Hallervorden make an interesting reading ¹.