Accumulation of iron in the brain is extremely dangerous as excess iron catalyzes the formation of free radicals, which have damaging effects to the brain. The iron accumulation characteristic of neuroferritinopathy particularly affects the cerebellum, basal ganglia, and motor cortex regions of the brain. Mechanism
The protein ferritin functions to sequester and release iron, acting as an iron buffering system in cells. Iron is essential to brain function in oxygen transport and cellular metabolism for example. However, careful control of iron is important as increased brain iron levels catalyze the formation of free radicals that create oxidative molecules via the Fenton Reaction. These oxidative molecules can cause oxidative brain damage. Iron that is bound to ferritin in nonreactive.Fenton Reaction
(1) Fe2+ + H2O2 → Fe3+ + HO• + OH−(2) Fe3+ + H2O2 → Fe2+ + HOO• + H+The ferritin protein is made up of heavy chain (H) and light chain (L) subunits. In neuroferritinopathy, the gene encoding the light chain is mutated. Several different mutation variations have led to diagnosis as neuroferritinopathy; all of these mutations occur in the light chain. A mutated light chain is believed to inhibit ferritins ability to effectively sequester and hold iron. Without control of iron, it is free to cause oxidative brain damage as described above.The concentration of iron in a healthy brain varies greatly from region to region. The specific regions of the brain that are associated with motor functions appear to have larger accumulations of iron than non-motor-related regions.
Hurler–Scheie syndrome is a genetic disorder caused by the buildup of glycosaminoglycans (GAGs) in various organ tissues. It is a cutaneous condition, also characterized by mild mental retardation and corneal clouding. Respiratory problems, sleep apnea, and heart disease may develop in adolescence.Hurler–Scheie syndrome is classified as a lysosomal storage disease. Patients with Hurler–Scheie syndrome lack the ability to break down GAGs in their lysosomes due a deficiency of the enzyme iduronidase. All forms of mucopolysaccharidosis type I (MPS I) are a spectrum of the same disease. Hurler-Sheie is the subtype of MPS I with intermediate severity. Hurler syndrome is the most severe form, while Scheie syndrome is the least severe form. Some clinicians consider the differences between Hurler, Hurler-Scheie, and Scheie syndromes to be arbitrary. Instead, they classify these patients as having "severe", "intermediate", or "attenuated" MPS I. See also
Mucopolysaccharidosis

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