We review the literature of genetic PD autopsies from cases with molecularly confirmed PD or parkinsonism and summarize main findings on SNCA (n = 25), Parkin (n = 20, 17 bi-allelic and 3 heterozygotes), PINK1 (n = 5, 1 bi-allelic and 4 heterozygotes), DJ-1 (n = 1), LRRK2 (n = 55), GBA (n = 10 Gaucher disease patients with parkinsonism), DNAJC13, GCH1, ATP13A2, PLA2G6 (n = 8 patients, 2 with PD), MPAN (n = 2), FBXO7, RAB39B, and ATXN2 (SCA2), as well as on 22q deletion syndrome (n = 3).
Specifically, mice overexpressing human wild-type aSyn under a broad neuronal promoter (Thy1-aSyn) present early, progressive motor and nonmotor deficits starting at 2-3 months, followed by parkinsonism with dopamine loss at 14 months.
The discoveries of genes related to hereditary forms of parkinsonism (PARK1, PARK2, PARK6, PARK7 and PARK8) have increased our understanding either of distinct subtypes of clinical expression in PD or its etiology.
Mutations in the alpha-synuclein (alpha-syn) gene are responsible for a rare familial parkinsonism syndrome, a finding that has led to extensive characterization of altered alpha-syn structure in sporadic Parkinson's disease (PD) and other neurodegenerative disorders.
Disorders characterized by α-synuclein (α-syn) accumulation, Lewy body formation and parkinsonism (and in some cases dementia) are collectively known as Lewy body diseases.
We found that over half of the reported cases with SNCA duplication had early-onset parkinsonism and non-motor features, such as dysautonomia, rapid eye movement sleep behavior disorder (RBD), hallucinations (usually visual) and cognitive deficits leading to dementia.
In a first feasibility study employing a novel ELISA, we found relatively low CSF alphaS concentrations in subjects with parkinsonism linked to synucleinopathy, PD and DLB.
Furthermore, studies in singly and doubly tg mice have shown that toxic conversion and accumulation can be accelerated by alpha-synuclein mutations associated with familial parkinsonism, by amyloid beta peptide 1-42 (Abeta 1-42), and by oxidative stress.
α-Synuclein transgenic mice reveal compensatory increases in Parkinson's disease-associated proteins DJ-1 and parkin and have enhanced α-synuclein and PINK1 levels after rotenone treatment.
We used a novel real-time quaking-induced conversion (RT-QuIC) assay to detect α-synuclein (α-syn) aggregates in cerebrospinal fluid (CSF) of 118 patients with parkinsonism of uncertain clinical etiology and 52 controls.
We screened for the p. A53TSNCA mutation a total of 347 cases of Greek origin with parkinsonism and/or dementia, collected over 15 years at the Neurogenetics Unit, Eginition Hospital, University of Athens.
In this study no one of our 85 patients of Serbian origin with young-onset (</= 45 years) dopa-responsive parkinsonism (YOP), previously proved negative forPARK1 and PARK2 mutations, had either spinocerebellar ataxia type 2 (SCA2) or SCA3 mutation.
NMR spectroscopy demonstrates that Parkinsonism-linked mutations greatly perturb specific tertiary interactions essential for the native state of alpha-synuclein.
These data suggest that phosphorylated α-synuclein accumulates in the retina in parallel with that in the brain, including in early stages preceding development of clinical signs of parkinsonism or dementia.
The effects of aberrant α-synuclein might include alteration of calcium homoeostasis or mitochondrial fragmentation and, in turn, mitochondrial dysfunction, which could link α-synuclein dysfunction to recessive and toxin-induced parkinsonism.
With the discovery of missense and multiplication mutations in the alpha-synuclein gene (SNCA) in familial parkinsonism, Lewy inclusions were found to stain intensely with antibodies raised against the protein.
Since the discovery in 1997 of the first heritable form of parkinsonism that could be linked to a mutation in a single gene, SNCA, many more genetic leads have followed (Parkin, DJ-1, PINK1, LRRK2, to name a few); these have provided us with many molecular clues to better explore the etiology of parkinsonism and have led to the dismantling of many previously held dogmas about Parkinson disease (PD).
Our study is the first to uncover the potential link between manganese exposure, altered miRNA expression and parkinsonism: manganese exposure causes overexpression of SNCA and FGF-20 by diminishing miR-7 and miR-433 levels.
These results indicated that the parkinsonism of the Sagamihara family seems not to be due to previously identified point mutations of alpha-synuclein, tau, or UCH-L1, or to exon deletion of parkin.
PD is characterized by intraneuronal accumulation of abnormal α-synuclein in brainstem while neurodegenerative parkinsonisms might be associated with accumulation of either α-synuclein, as in the case of Multiple System Atrophy (MSA) or tau, as in the case of Corticobasal Degeneration (CBD) and Progressive Supranuclear Palsy (PSP), in other disease-specific brain regions.
Smad3 deficiency promotes strong catabolism of DA in the striatum (ST), decrease trophic and astrocytic support to dopaminergic neurons and may induce α-synuclein aggregation, which may be related to early parkinsonism.