Mutations in five causative genes combined [alpha-Synuclein (SNCA), Parkin, PTEN-induced kinase 1 (PINK1), DJ-1, Leucine-rich repeat kinase 2 (LRRK2)] account for 2-3% of all cases with classical parkinsonism, often clinically indistinguishable from idiopathic Parkinson's disease.
Twelve- to sixteen-month-old (G2019S) LRRK2 transgenic mice prepared by us displayed progressive degeneration of substantia nigra pars compacta (SNpc) dopaminergic neurons and parkinsonism phenotypes of motor dysfunction.
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 findings in a representative series of index cases from families with ADPD emphasize the important contribution of LRRK2G2019S and GBA (L444P and N370S) mutations to parkinsonism in Brazilian families.
We discuss the roles of heterozygous LRRK2 mutations and heterozygous parkin and PINK1 mutations in the development of parkinsonism, and propose an integrated aetiological model for this complex disease.
In this brain bank-based series, LRRK2G2019S mutation occurred in patients with parkinsonism associated with either typical brainstem LB pathology or non-specific nigral degeneration.
Here, we used a two-step approach to identify compounds from the FDA-approved licensed drug library that could suppress neurite degeneration in LRRK2-G2019Sparkinsonism.
We conducted PET of 2 subjects and neuropathologically examined 8 subjects in the same family from the Sagamihara district, the original source of PARK8-linked parkinsonism (I2020T mutation).
Mutations in the leucine-rich repeat kinase 2 (LRRK2) gene have been identified as a much more common cause for dominant PS, especially in certain ethnic groups, while mutations in the parkin gene, in DJ-1, PINK1 and ATP13A2 cause autosomal recessive parkinsonism of early onset.
Therefore, the LRRK2 mutation has a relatively high frequency in the AJ population, is not fully penetrant for parkinsonism in the elderly, and does not appear to be commonly associated with late-onset dementia.
We have identified Family SK where Lrrk2G2019S segregates with slowly progressive parkinsonism and the affected proband has tau-immunopositive neurofibrillary tangle pathology.
These results not only represent the largest replication data affirming the association between PD and all the six genes/loci in Chinese, but for the first time suggest that multiple PD-associated genetic factors modify both the penetrance and AAO of LRRK2parkinsonism.
Understanding the molecular function of the LRRK2 protein and its associated pathways might elucidate the switch between Lewy body pathology and neurofibrillary tangles, and holds promise for prospective therapeutics that might slow or halt progression of many forms of parkinsonism.