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Manganese is essential for several metabolic pathways but becomes toxic in excessive amounts. Manganese levels in the body are therefore tightly regulated, but the responsible protein(s) remain incompletely known. We studied two consanguineous families with neurologic disorders including juvenile-onset dystonia, adult-onset parkinsonism, severe hypermanganesemia, polycythemia, and chronic hepatic disease, including steatosis and cirrhosis. We localized the genetic defect by homozygosity mapping and then identified two different homozygous frameshift SLC30A10 mutations, segregating with disease. SLC30A10 is highly expressed in the liver and brain, including in the basal ganglia. Its encoded protein belongs to a large family of membrane transporters, mediating the efflux of divalent cations from the cytosol. We show the localization of SLC30A10 in normal human liver and nervous system, and its depletion in liver from one affected individual. Our in silico analyses suggest that SLC30A10 possesses substrate specificity different from its closest (zinc-transporting) homologs. We also show that the expression of SLC30A10 and the levels of the encoded protein are markedly induced by manganese in vitro. The phenotype associated with SLC30A10 mutations is broad, including neurologic, hepatic, and hematologic disturbances. Intrafamilial phenotypic variability is also present. Chelation therapy can normalize the manganesemia, leading to marked clinical improvements. In conclusion, we show that SLC30A10 mutations cause a treatable recessive disease with pleomorphic phenotype, and provide compelling evidence that SLC30A10 plays a pivotal role in manganese transport. This work has broad implications for understanding of the manganese biology and pathophysiology in multiple human organs.

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These data confirm substantial neocortical volume loss in MS patients and suggest that neocortical GM pathology may occur early in the course of the disease in both RR and PP MS patients and contribute significantly to neurologic impairment. Although a proportion of this neocortical pathology may be secondary to WM inflammation, the extent of the changes suggests that, especially in patients with PP MS, an independent neurodegenerative process also is active.

Neurodegenerative disorders affect almost 30 million individuals leading to disability and death. These disorders are characterized by pathological changes in disease-specific areas of the brain and degeneration of distinct neuron subsets. Despite the differences in clinical manifestations and neuronal vulnerability, the pathological processes appear similar, suggesting common neurodegenerative pathways. Apoptosis seems to play a key role in the progression of several neurologic disorders like Alzheimer's disease, Parkinson's disease, Huntington's disease, and amyotrophic lateral sclerosis as demonstrated by studies on animal models and cell lines. On the other hand, research on human brains reported contradictory results. However, many dying neurons have been detected in brains of patients with neurodegenerative diseases, and these conditions are often associated with significant cell loss accompanied by typical morphological features of apoptosis such as chromatin condensation, DNA fragmentation, and activation of cysteine-proteases, caspases. Cell death and neurodegenerative conditions have been linked to oxidative stress and imbalance between generation of free radicals and antioxidant defenses. Multiple sclerosis, stroke, and neurodegenerative diseases have been associated with reactive oxygen species and nitric oxide. Here we present an overview of the involvement of neuronal apoptosis and oxidative stress in the most important neurodegenerative diseases, mainly focusing the attention on several genetic disorders, discussing the interaction between primary genetic abnormalities and the apoptotic pathways.