Iron accumulation in syndromes of neurodegeneration with brain iron accumulation 1 and 2: causative or consequential?
- 1Institute of Neurology, Queen Square, University College London, London, UK
- 2Schilling Department of Clinical and Molecular Neurogenetics at the Department of Neurology, University of Luebeck, Lubeck, Germany
- Professor K P Bhatia, Sobell Department, Institute of Neurology, Queen Square, University College London, London WC1N 3BG, UK;
- Accepted 22 December 2008
- Published Online First 15 January 2009
Syndromes of neurodegeneration with brain iron accumulation (NBIAs) are inherited movement disorders characterised by a progressive degeneration of the nervous system. There has been recent progress in the work-up of these disorders. While for some of the NBIA disorders, such as neuroferritinopathy,1 causative mutations in genes involved in brain iron metabolism have been found, for the two core syndromes, the link to iron remains speculative. The two main NBIA syndromes are pantothenate kinase associated neurodegeneration (PKAN, previously also called Hallervorden–Spatz disease or NBIA type 1) caused by mutations in the PANK2 gene on chromosome 20,2 and NBIA type 2, the condition of infantile neuroaxonal dystrophy due to mutations in the PLA2G6 gene located on chromosome 22.3 4 In the following, we will concentrate on the two autosomal recessive subtypes which are not directly related to iron metabolism.
The currently thought-to-be “classic” phenotype of these disorders, NBIA types 1 and 2, is that of a young onset progressive extrapyramidal–pyramidal syndrome with visual disturbance.5 It has been claimed that iron deposition in the basal ganglia is one of the hallmark features and hence the term NBIA was coined. For PKAN, the deposition imaging pattern resembling an “eye of the tiger” has been proposed to be a characteristic, indeed pathognomonic, feature.5 …