The nosology of Hallervorden-spatz disease.

The development of magnetic resonance imaging has increased the number of clinical and pathological reports of Hallervorden-Spatz disease and Hallervorden-Spatz syndrome. The case-to-case variability is considerable. However, if gene loci and basic pathogenetic mechanisms are to be appreciated, it is imperative that like cases be compared and studied. The designation Hallervorden-Spatz disease should be reserved for the pediatric neurodegenerative disorder, recognizing that it occurs either as a familial or a sporadic disorder. The diagnosis of Hallervorden-Spatz syndrome is non-specific and encompasses a number of distinctive disorders, each having the pallidal triad of iron deposition, axonal spheroids, and gliosis. Clinically or pathologically distinct groups include (a) female patients with dementia, quadriparesis, and neurofibrillary tangles; (b) cases with Lewy bodies; and (c) cases with or without lipid abnormalities which have acanthocytosis and pigmentary retinal degeneration. Adult-onset cases are quite variable, both clinically and pathologically. Iron deposition in the globus pallidus separates these disorders from others in which axonal spheroids occur. Undoubtedly, the pallidal changes are related, some being primary and other possibly epiphenomena. Pathogenetic insights can only be achieved by investigating and comparing like cases.