alpha-synuclein and Hepatolenticular-Degeneration

Juvenile parkinsonism is arbitrarily defined as parkinsonian symptoms and signs presenting prior to 21 years of age. Levodopa-responsive juvenile parkinsonism that is consistent with diagnostic criteria for Parkinson's disease is most often caused by mutations in the PARK-Parkin, PARK-PINK1, or PARK-DJ1 genes. However, many other genetic and acquired parkinsonian disorders presenting in childhood or young adulthood are being reported, often with atypical features, such as presence of other movement disorders, cognitive decline, and psychiatric symptoms. The genetic landscape of juvenile parkinsonism is rapidly changing with the discovery of new genes. Although the mainstay of treatment remains levodopa, other symptomatic therapies such as botulinum toxin for focal dystonia, supportive medical therapies, and deep brain stimulation in select cases, may also be used to provide the most optimal long-term outcomes. Since the topic has not been reviewed recently, we aim to provide an update on genetics, differential diagnosis, evaluation, and treatment of juvenile parkinsonism.

Topics: Adolescent; alpha-Synuclein; Antiparkinson Agents; Child; Child, Preschool; Deep Brain Stimulation; Diagnosis, Differential; DiGeorge Syndrome; Dystonic Disorders; Genetic Diseases, X-Linked; Hepatolenticular Degeneration; Humans; Huntington Disease; Levodopa; Parkinsonian Disorders; Protein Deglycase DJ-1; Protein Kinases; Spinocerebellar Ataxias; Ubiquitin-Protein Ligases; Young Adult

The Long-Evans Cinnamon (LEC) rat shows age-dependent hepatic manifestations that are similar to those of Wilson's disease (WD). The pathogenic process in the brain has, however, not been evaluated in detail due to the rarity of the neurological symptoms. However, copper accumulation is noted in LEC rat brain tissue from 24 weeks of age, which results in oxidative injuries. The current study investigated the gene expression profiles of LEC rat brains at 24 weeks of age in order to identify the important early molecular changes that underlie the development of neurological symptoms in WD. Biological ontology-based analysis revealed diverse altered expressions of the genes related to copper accumulation. Of particular interest, we found altered expression of genes connected to mitochondrial respiration (Sdhaf2 and Ndufb7), calcineurin-mediated cellular processes (Ppp3ca, Ppp3cb, and Camk2a), amyloid precursor protein (Anks1b and A2m) and alpha-synuclein (Snca). In addition to copper-related changes, compensatory upregulations of Cp and Hamp reflect iron-mediated neurotoxicity. Of note, reciprocal expression of Asmt and Bhmt is an important clue that altered S-adenosylhomocysteine metabolism underlies brain injury in WD, which is directly correlated to the decreased expression of S-adenosylhomocysteine hydrolase in hepatic tissue in LEC rats. In conclusion, our study indicates that diverse molecular changes, both variable and complex, underlie the development of neurological manifestations in WD. Copper-related injuries were found to be the principal pathogenic process, but Fe- or adenosylhomocysteine-related injuries were also implicated. Investigations using other animal models or accessible human samples will be required to confirm our observations.

Topics: alpha-Synuclein; Animals; Antimicrobial Cationic Peptides; Brain; Cell Transformation, Neoplastic; Cluster Analysis; Copper; Disease Models, Animal; Gene Expression Profiling; Gene Expression Regulation; Hepatolenticular Degeneration; Hepcidins; Humans; Iron; Liver; Mitochondria; Neurons; Oligonucleotide Array Sequence Analysis; Rats; Rats, Inbred LEC; Real-Time Polymerase Chain Reaction; Reproducibility of Results; S-Adenosylhomocysteine; Time Factors; Visual Pathways