Preliminary observation of elevated levels of nanocrystalline iron oxide in the basal ganglia of neuroferritinopathy patients

Abstract

Magnetometry analysis of brain tissue sub-samples from two neuroferritinopathy patients provides a preliminary indication that the amount of magnetic iron compounds associated with this rare disease is significantly larger than in age/sex-matched controls. The primary iron compounds contributing to the remnant magnetization of the tissue above 50 K and at body temperature are both blocked and superparamagnetic (SPM) biogenic magnetite (Fe3O4) and/or maghemite (gamma-Fe2O3). The concentration of SPM magnetite is significant and appears to be proportional to the concentration of ferritin, which varies with progression of the disease. The mutated ferritin protein appears to be responsible for the presence of iron oxide nano-particules, which in turn could be responsible for extensive damage in the brain.

Fig. 1

The isothermal remanence of magnetization and their empirical fit to eq. 1, for sample 1 fraction 1 at 5 K (■) and 50 K (●), and for sample 2 fraction 1 at 5 K (□) and 50 K (○).

Fig. 2

IRM curve of HSF measured at 5 K and fit to a second-degree polynomial: 2.142 10⁻⁵H – 6.407 10⁻¹⁰ H².

Fig. 3

Temperature dependence of the magnetization of patient 1 fraction 1, measured in zero-field cooled and field cooled conditions with a field of 200 Oe. The inset shows the difference between the two curves above 25 K where there is no contribution from ferritin.

Fig. 4

The thermal decay of remanence measured on patient 2 fraction 2, through the Verwey transition, in zero-field, and upon cooling; after having applied a field of 1 Tesla.